{`#++ @@@ @@@@ #6s5VDr+ + EN DB +d @&6 : jZR >~  e N$ H m 2uz    4 T) V#8 Lanners19836ALRTbMRNBNDLCDEF CNTLCURS:DITLRDLOG FREFICN#LDEFmachMENU&nrctPICTPROC SHOW^SICNjSTR STR# sUPL*sysz6versBcicnZcdev~INITmst#06 70oG=y !100$?1.684*G;Oh:5 PP<p9;>+=/7 y7?P>s1=984t;*:5 <)7 !"!" L\0M`1Nd>88: T0E G1I\G2NGϜ<Rt4_GL5wGτ3Gϸ= / J:  "; 8 o9 00G' Lanners1984 Lanners1984G Lanzer1994q Le Bras1988m Lee19882 Leech1982 Leech1983 Leech19840 Leech1988* Leech1989 Leech1990q Lenstra1988\ Liu1992Q Liu1997 Looareesuwan1985v Looareesuwan19878] Looareesuwan1992(S Luc1996 Lyandvert1981w Lyon19878Macaluso1985ef Mackenstedt1989j Mackenstedt1989 MacPherson1985+V Maeno1994* Magowan1989o Maracic1988: Maracic1989~ Marsh1986u Marsh1987w Marsh19877 Marsh1988 Matsumoto1987m Matsumoto1988o Matsumoto1988: Matsumoto1989R Matsumoto1996 McBride1984McGregor19833fMehlhorn19899jMehlhorn19898HMercereau-Puijalon1994 Miller198112 Miller19828 Miller19838 Miller19833 Miller19833 Miller19848 Miller19855~ Miller19869V Millet19944[Morehead19923% Motyl1979 Motyl1983y Myint1987aNagatake19929 Nagel1985 Nagel1985[Nakamura19923aNakamura19929S Nakano19966VNakazawa1994@{ Naslund1986* Nelson19898 Ng1989ro Nussenzweig1988Q Oh19978 Olson1985 Oo1987iy Oo1987d Oo19901a Ozaki1992\ Palek1992Q Palek1997 Panton198599 Panton19877w Panton19877m Panton198819 Parra1987$ Parra1991YPasloske1993 1 Paulie19919Pavlovec1987nHPereira da Silva1994hPerlmann19891Perlmann1991o^ Perry1992*Petersen19893Peterson1985T Peyrol19966vPhillips1987e| Pologe1986( Pologe1987a Pongponratn1992 Pouliquen1998TPouvelle19966` Prudhomme1992S Rabbege1996j Raether1989 Rashid19909  Rashid19909 Rashid19919$ Rashid19919Raventos19853Raventos-Suarez1985| Ravetch1986 Ravetch1987G Ravetch1994D Reeder1997 Reese1978% Reese1979 Reese1979 Reese1983 Reese1984 Reese1984 Reese1987 Reese19879 Rener1987T Robert19966 Roberts1985~ Roberts1986u Rock198780 Rock19888 Rosario1984 Rosenbaum1985m Rossan19881n Roth198881Ruangjirachuporn1991n Saint1987q Samso1988w Saul198780 Saul19888 Scanlon1987 Schmidt19812 Schmidt1982y Schoene1987t Semoff19877{ Sharma198683 Sharma198784 Sharma19878L Sharma1988;I Sharma1991sc Sharma19911F Sharma1996E Sharma19979O Sharma19978 Sherman1983 Sherman1983} Sherman1986x Sherman1987l Sherman1988k Sherman1989` Sherman1992Sherwood1984Sherwood1985@~Sherwood19866wSherwood198710Sherwood198837Sherwood1988 Shio19871R Shiraishi1996i Silva1989n Sinha1988b Smith1991^ Smith1992_ Smith1992` Smith1992 Spitalnik1985~ Spitalnik19867 Spitalnik1988 Stahl1987 Stanley1981< Stanley1982= Stanley1983 Stanley1984 Stanley1987 Stanley19879 Stearns19877 Suarez19889] Suntharasamai1992X Suzuki19939U Suzuki1995RTakeuchi19966 Tan Ariya1988R Tandler1996YTaraschi199399 Taylor198780 Taylor19888d Taylor19909^ Tegoshi1992_ Tegoshi1992a Tegoshi1992 Tershakovec1981 Thaithong1984y Than19878S Todd19969: Torii1989R Torii1996 Trager19777 Trager19787% Trager19797 Trager19813< Trager19821= Trager19832' Trager19844 Trager19844g Trager19891  Triglia1987 Udeinya19812 Udeinya1982 Udeinya1983h Udomsangpetch1989b Udomsangpetch19919 Uni1987w Uni1987Yvan Schravendijk1993@ Vernot19858AVernot Hernandez1984Wahlgren19833hWahlgren1989KWahlgren199001Wahlgren1991o Walker19844D Waller1997Walliker19844 Warrell1985 Warrell1985v Warrell1987b Webster1991^ Webster1992_ Webster1992 Wellems1987G Wertheimer1994; White1985D Wickham1997vWickramasinghe1987+ Wilkinson1990xWinograd19871kWinograd19898* Wollish1989 Wycherley1990 Yang1988 Yang19901 Yang19909 Yang19919$ Yang19911$ Yang1991119$ Yang19911 Yang1991119$ Yang199119919$ Yang199119919$ Yang19911ng19919$ Yang1991119$ Yang199119919$ Yang1991119919$ Yang1991119$ Yang1991119$ Yang1991119$ Yang19911$ Yang199119919$ Yang199119919$ Yang1991119$ Yang1991119$ Yang19911$ Yang19911$ Yang1991119$ Yang1991119$ Yang19911$ Yang199119919$ Yang1991119$ Yang1991119$ Yang1991119$ Yang19911$ Yang1991119$ Yang1991119$ Yang1991119$ Yang19911ngponratn1992TPouvelle19966` Prudhomme1992S Rabbege1996j Raether1989 Rashid19909  Rashid19909 Rashid19919$ Rashid19919Raventos19853.Raventos19853M Ravetch1986 Ravetch1987G Ravetch1994D Reeder1997P Reeder19978% Reese1979 Reese1984 Reese1987 Reese19879 Rener1987T Robert199660 Rock19888 Rosenbaum1985m Rossan19881n Roth198881Ruangjirachuporn1991n Saint1987) Samso1988q Samso19880 Saul19888 Scanlon19872 Schmidt1982! Sharma198683 Sharma198784 Sharma19878L Sharma1988;I Sharma1991sJ Sharma1991sc Sharma19911F Sharma1996C Sharma1997WE Sharma19979O Sharma19978 Sherman1983B Sherman1987l Sherman1988k Sherman1989` Sherman1992Sherwood19840Sherwood198837Sherwood1988 Shio19871R Shiraishi1996i Silva1989n Sinha1988b Smith1991^ Smith1992_ Smith1992` Smith19927 Spitalnik1988 Stahl1987; Stanley1981< Stanley1982= Stanley1983 Stanley1987 Stanley19879 Stearns19877 Suarez19889] Suntharasamai1992X Suzuki19939U Suzuki1995RTakeuchi19966 Tan Ariya1988R Tandler1996YTaraschi199399 Taylor198780 Taylor19888d Taylor19909^ Tegoshi1992_ Tegoshi1992a Tegoshi1992; Tershakovec1981S Todd19969: Torii1989R Torii1996 Trager19777% Trager19797; Trager19819< Trager19821= Trager19832' Trager19844g Trager19891  Triglia19872 Udeinya1982? Udomsangpetch1989h Udomsangpetch1989b Udomsangpetch19919 Uni1987Yvan Schravendijk1993@ Vernot19858AVernot Hernandez1984Wahlgren19833?Wahlgren1989hWahlgren1989KWahlgren199001Wahlgren1991oD Waller1997P Waller19978b Webster1991^ Webster1992_ Webster1992 Wellems1987G Wertheimer1994;D Wickham1997P Wickham1997 Wilkinson1990BWinograd1987dkWinograd19898* Wollish1989 Wycherley1990 Yang1988 Yang19901 Yang19909 Yang19919$ Yang19911P/ NZX%"&-. )!( * 0=@J@g/. ?./ NO `?./. / N*O (_N^NuNV/ (nN" n mJBg T/(2`0=@Bg T/(2/.Bh0Bg T/(2`0n=@Jng(?./ Nr\`Jn oBg T/(2/.Hxh0(_N^NuNV/ NL(QJng"B/. Z -@Jg?./.N\(_N^ _ONNV/ (nHn/ NP0.nH(V@=@0.nn=@0. N:2"0.D@=@` =n`0.D@=@` =n`BnBg T/(2`0=@Jnl&Bg T/(2a0n=@0.nl2=n`*Jno$Bg T/(2-*. . ""&---..) *** )""! !&*  & .(" ! ))**-!%* .@bhXN g=<5Trager, W. Lanners, H.N. Stanley, H.A. Langreth, S.G. 1983lfImmunization of owl monkeys to Plasmodium falciparum with merozoites from cultures of a knobless cloneParasite Immunol5n225-236 0195 Ref1189330556 Trager, W.6/Erythrocyte knobs and malaria [letter; comment]Animal Aotus trivirgatus Cell Adhesion Erythrocytes/parasitology/*ultrastructure Malaria/*blood Plasmodium falciparum/physiology Nature 1989 340s 6232 352`YTriglia, T. Stahl, H. D. Crewther, P. E. Scanlon, D. Brown, G. V. Anders, R.F. Kemp, D.J./rkThe complete sequence of the gene for the knob-associated histidine-rich protein from Plasmodium falciparumg EMBO J 19876 1413-1419/ Ref11u81225861F@Udeinya, I. J. Schmidt, J. A. Aikawa, M. Miller, L. H. Green, I.d^Falciparum malaria-infected erythrocytes specifically bind to cultured human endothelial cellsAnimal Aotus trivirgatus Cells, Cultured Endothelium/microbiology Erythrocytes/*microbiology/ultrastructure Female Human Microscopy, Electron Plasmodium falciparum/*pathogenicity Pregnancy Umbilical VeinsErythrocytes infected with the late stages of the human malarial parasite Plasmodium falciparum became attached to a subpopulation of cultured human endothelial cells by knoblike protrusions on the surface of the infected erythrocytes. Infected erythrocytes did not bind to cultured fibroblasts; uninfected erythrocytes did not bind to either endothelial cells or fibroblasts. The results suggest a specific receptor-ligand interaction between endothelial cells and a component, components, in the knobs of the infected erythrocytes.aScience 1981 213. 4507 555-783219237@:Udeinya, I. J. Miller, L. H. McGregor, I. A. Jensen, J. B.zsPlasmodium falciparum strain-specific antibody blocks binding of infected erythrocytes to amelanotic melanoma cellsIAnimal *Antibodies Antigen-Antibody Complex Aotus trivirgatus/immunology Erythrocytes/*immunology Human Immune Sera Melanoma/*immunology Plasmodium falciparum/*immunology Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S.jdAn important feature of Plasmodium falciparum malaria which differentiates it from other human malarias is that erythrocytes infected with trophozoites and schizonts are not present in the peripheral blood but are sequestered along capillary and venular endothelium. Infected erythrocytes attach via parasite-induced ultrastructural modifications on the surface of the infected cells, called 'knobs'. This sequestration may be important for parasite survival because it prevents infected erythrocytes from circulating through the spleen where they could be eliminated. We have established an in vitro correlate of sequestration and used it to demonstrate that immune sera from repeatedly infected Aotus monkeys inhibit binding of infected erythrocytes to endothelial cells. We have investigated whether antiserum that blocks binding of one isolate of P. falciparum to target cells can block or reverse binding of other isolates. We report here that sera which block or reverse binding are strain- specific, indicating that the corresponding antigens on the surface of the infected erythrocytes are strain (isolate)-specific. Nature 1983 303 5916 429-3189238525HBUdomsangpetch, R. Aikawa, M. Berzins, K. Wahlgren, M. Perlmann, P.Cytoadherence of knobless Plasmodium falciparum-infected erythrocytes and its inhibition by a human monoclonal antibody [see comments]Animal *Antibodies, Monoclonal Antigens, Protozoan/immunology Cell Adhesion *Endothelium, Vascular Erythrocytes/physiology/*parasitology/ultrastructure Fluorescent Antibody Technique Glutamates Human Melanoma Microscopy, Electron Plasmodium falciparum/immunology/*physiology Repetitive Sequences, Nucleic Acid Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S. Tumor Cells, CulturedNRed blood cells infected with mature stages of the malaria parasite Plasmodium falciparum bind to the endothelial lining of capillaries and venules. This sequestration is important for the survival of the parasite but may have severe consequences for the host. For example, it is involved in the causation of cerebral malaria which carries 25% mortality. Knob-like protrusions present on the surface of infected erythrocytes have been considered necessary but not sufficient for this cytoadherence. Here we describe the adhesion to endothelial cells of infected erythrocytes which do not have knobs. A human monoclonal antibody (33G2) which was specific for an epitope containing regularly spaced dimers of glutamic acid present in the repeated amino-acid sequences of some defined P. falciparum antigens was found to inhibit cyto-adherence and may therefore be an important reagent for elucidating the molecular basis of parasite sequestration.e Nature 1989 3389 6218 763-591253677@:Udomsangpetch, R. Brown, A. E. Smith, C. D. Webster, H. K.HARosette formation by Plasmodium coatneyi-infected red blood cellsAnimal Edetic Acid/pharmacology Erythrocytes/immunology/*parasitology Heparin/pharmacology Macaca mulatta Malaria/*blood/parasitology Plasmodium/immunology/*physiology *Rosette FormationAnimal models are needed for the study of cytoadherence in falciparum malaria. Red blood cell (RBC) rosette formation is one type of cytoadherence and appears to be associated with knob formation, endothelial cell adhesion and sequestration of Plasmodium-infected RBCs. Since Plasmodium coatneyi-infected RBCs develop knobs and sequester, we hypothesized that they also form rosettes. RBCs from P. coatneyi-infected rhesus monkeys (Macaca-mulatta) were collected, allowed to mature overnight in vitro and found to form rosettes as hypothesized. This observation adds to the known falciparum-like characteristics of P. coatneyi, and suggests that the Macaca mulatta-P. coatneyi model may be appropriate for pathophysiologic studies of cytoadherence.Am J Trop Med Hygm 1991444 399-401p*$Vernot, Hernandez Jp Heidrich, H. G.lfThe relationship to knobs of the 92,000 D protein specific for knobby strains of Plasmodium falciparum Z Parasitenkd 198571 41-51 Ref11Da , C.494142585`ZAikawa, M. Pongponratn, E. Tegoshi, T. Nakamura, K. Nagatake, T. Cochrane, A. Ozaki, L. S.TMA study on the pathogenesis of human cerebral malaria and cerebral babesiosis 82Animal Babesia/isolation & purification Babesiosis/*etiology/pathology Brain Diseases/etiology/pathology/*parasitology Capillaries/pathology/parasitology Cattle Cattle Diseases/*etiology/pathology/parasitology Cerebrovascular Circulation Erythrocytes/parasitology Human Intestine, Small/pathology Lung/pathology Malaria, Cerebral/*etiology/pathology Malaria, Falciparum/*etiology/pathology Microscopy, Electron Myocardium/pathology Plasmodium falciparum/isolation & purification Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S.Cerebral complications are important, but poorly understood pathological features of infections caused by some species of Plasmodium and Babesia. Patients dying from P. falciparum were classified as cerebral or non-cerebral cases according to the cerebral malaria coma scale. Light microscopy revealed that cerebral microvessels of cerebral malaria patients were filled with a mixture of parasitized and unparasitized erythrocytes, with 94% of the vessels showing parasitized red blood cell (PRBC) sequestration. Some degree of PRBC sequestration was also found in non-cerebral malaria patients, but the percentage of microvessels with sequestered PRBC was only 13%. Electron microscopy demonstrated knobs on the membrane of PRBC that formed focal junctions with the capillary endothelium. A number of host cell molecules such as CD36, thrombospondin (TSP) and intercellular adhesion molecule I (ICAM-1) may function as endothelial cell surface receptors for P. falciparum-infected erythrocytes. Affinity labeling of CD36 and TSP to the PRBC surface showed these molecules specifically bind to the knobs. Babesia bovis infected erythrocytes produce projections of the erythrocyte membrane that are similar to knobs. When brain tissue from B. bovis-infected cattle was examined, cerebral capillaries were packed with PRBC. Infected erythrocytes formed focal attachments with cerebral endothelial cells at the site of these knob- like projections. These findings indicate that cerebral pathology caused by B. bovis is similar to human cerebral malaria. A search for cytoadherence proteins in the endothelial cells of cattle may lead to a better understanding of the pathogenesis of cerebral babesiosis.Mem Inst Oswaldo Cruze 199287Suppl 3297-301%B$ {8701706281Kilejian, A. Sharma, Y. D. Karoui, H. Naslund, L.Hd]Histidine-rich domain of the knob protein of the human malaria parasite Plasmodium falciparumGAmino Acid Sequence DNA/metabolism Histidine/*analysis Human Nucleic Acid Hybridization Peptides/analysis/*biosynthesis/genetics Plasmodium falciparum/*metabolism Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S.Membranes of erythrocytes infected with the human malaria parasite Plasmodium falciparum develop protrusions called knobs. These structures are essential for the survival of the parasite in the host, and their induction requires the synthesis of the knob protein by the parasite. We describe the isolation of a cDNA clone encoding the amino- terminal half of the knob protein. A cDNA library was constructed from RNA prepared from ring stages of a P. falciparum isolate that has retained its ability to induce knobs (knob+ phenotype). A synthetic oligonucleotide probe encoding polyhistidine was used to isolate the cDNA clone, which encodes the amino-terminal half of a polypeptide with all the known attributes of the knob protein. The gene is not transcribed in variants that do not synthesize the knob protein and thereby cannot induce knobs (knob- phenotype). The apparent lack of transcription in knob- variants is due to different mechanisms: although the gene is present in one knob- isolate, it has been deleted in a cloned knob- variant. The primary structure of the polypeptide deduced from a partial sequence of the cDNA is distinctly different from other malarial histidine-rich polypeptides. The amino-terminal sequence shows the characteristic features of a signal peptide. This is followed by a histidine-rich domain and a subsequent region which contains one histidine. Peptide map analysis of the knob protein is consistent with the structural features deduced from the sequence analysis of the cDNA.Proc Natl Acad Sci U S A 198683207938-41<6Kilejian, A. Yang, Y. F. Cochrane, A. H. Rashid, M. A.|uHomologous sequences in Plasmodium cynomolgi and the gene of the histidine-rich knob protein of Plasmodium falciparumMol Biochem Parasitol 1990382 291-3m@9Kilejian, A. Rashid, M. A. Aikawa, M. Aji, T. Yang, Y. F. 1991lfSelective association of a fragment of the knob protein with spectrin, actin and the red cell membraneMol Biochem Parasitol442175-182d60Kilejian, A. Rashid, M. A. Parra, M. Yang, Y. F.`YSequence of the knob protein of Plasmodium falciparum recognized by a monoclonal antibodyd 1991Mol Biochem Parasitoll482a231-233d79111660<5Langreth, S. G. Jensen, J. B. Reese, R. T. Trager, W..(Fine structure of human malaria in vitroAnimal Cells, Cultured Comparative Study Erythrocytes/*parasitology Haplorhini Human Malaria/*parasitology Organoids/ultrastructure Plasmodium falciparum/growth & development/*ultrastructure Support, U.S. Gov't, P.H.S.The erythrocytic cycle of the human malaria parasite, Plasmodium, falciparum, was examined by electron microscopy. Three strains of parasites maintained in continuous culture in human erythrocytes were compared with in vivo infections in Aotus monkeys. The ultrastructure of P. falciparum is not altered by continuous cultivation in vitro. Mitochondria contain DNA-like filaments and some cristae at all stages of the erythrocytic life cycle. The Golgi apparatus is prominent at the schizont stage and may be involved in the formation of rhoptries. In culture, knob-like protrusions first appear on the surface of trophozoite-infected erythrocytes. The time of appearance of knobs on cells in vitro correlates with the life cycle stage of parasites which are sequestered from the peripheral circulation in vivo. Knob material of older parasites coalesces and forms extensions from the erythrocyte surface. Some of this material is sloughed from the host cell surface. The parasitophorous vacuole membrane breaks down in erythrocytes containing mature merozoites both in vitro and in vivo. Merozoite structure is similar to that of P. knowlesi. The immature gametocytes in culture have no knobs. J Protozool  1978254 443-52:4Langreth, S. G. Reese, R. T. Motyl, M. R. Trager, W.jdPlasmodium falciparum: loss of knobs on the infected erythrocyte surface after long-term cultivation Exp Parasitol< 197948213-219 Ref11 6tnCulvenor, J. G. Langford, C. J. Crewther, P. E. Saint, R. B. Coppel, R. L. Kemp, D.J. Anders, R.F. Brown, G.V. 1987pjPlasmodium falciparum: identification and localization of a knob protein antigen expressed by a cDNA clone Exp Parasitol631 58-67 0264 Ref11  AuthorsJournalsKeywords   *Y m>y87140149XQOo, M. M. Aikawa, M. Than, T. Aye, T. M. Myint, P. T. Igarashi, I. Schoene, W. C. 2,Human cerebral malaria: a pathological studyTMAdolescence Adult Basement Membrane/metabolism/parasitology Brain/pathology/parasitology/ultrastructure Brain Diseases/*pathology/parasitology Child Child, Preschool Female Human IgG/metabolism Malaria/*pathology/parasitology Male Microscopy, Electron Middle Age Plasmodium falciparum/isolation & purification Support, Non-U.S. Gov'tdd^The following report using light and electron microscopic and immunological techniques is based on a series of 19 Burmese patients who died of cerebral malaria. The principal change was blockage of cerebral capillaries by Plasmodium falciparum-infected erythrocytes. Ring hemorrhages and segmental necrosis of cerebral capillaries were common. Cerebral edema was variable in these cases. Electron-dense knobs, 40 X 80 nm in size, which protruded from the membrane of infected erythrocytes, formed focal junctions between endothelial cells and erythrocytes. These junctions resulted in the entrapment of erythrocytes and caused blockage in the capillary lumen. Immunoperoxidase study revealed that P. falciparum antigens and IgG deposits in the capillary basement membrane. This implies that damage to the cerebral capillary could be related to immune mechanisms.J Neuropathol Exp Neurol 1987462 223-3189301587Panton, L. J. Rossan, R. N. Escajadillo, A. Matsumoto, Y. Lee, A. T. Labroo, V. M. Kirk, K. L. Cohen, L. A. Aikawa, M. Howard, R. J.leIn vitro and in vivo studies of the effects of halogenated histidine analogs on Plasmodium falciparumdZTAmino Acids/metabolism Animal *Antimalarials Aotus trivirgatus Cell Membrane/ultrastructure Histidine/*analogs & derivatives/pharmacology In Vitro Malaria/prevention & control Microscopy, Electron Plasmodium falciparum/*drug effects/metabolism/parasitology Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S.The effects of four halogenated analogs of histidine on in vitro growth of Plasmodium falciparum malaria parasites were monitored by measurement of the incorporation of 3H-labeled amino acids into parasite proteins and by light and electron microscopy. The uptake of [3H]isoleucine was reduced to 50% of the control value by addition of 70 microM 2-fluoro-L-histidine (2-F-HIS) or 420 microM 2-iodo-L- histidine (2-I-HIS). [3H]histidine uptake into acid-insoluble material was affected equally by these two compounds, 50% inhibition resulting at 200 microM concentration. Morphological analysis of parasite development proved a sensitive assay, since development of mature trophozoites was inhibited 50% by 25 microM 2-F-HIS or 100 2-I-HIS. Electron microscopy studies suggested different mechanisms of action of 2-F-HIS and 2-I-HIS on P. falciparum. 2-F-HIS produced a decrease in knob number at the erythrocyte surface and accumulation of electron- dense material under the parasite membrane. 2-I-HIS had no obvious effect on knobs or electron-dense material but affected parasite morphology. Surprisingly, 2-chloro-L-histidine and 2-bromo-L-histidine did not inhibit P. falciparum in vitro, even though their halogen atom substituents are intermediate in size between F and I atoms. 2-F-HIS and 2-I-HIS were tested in vivo against P. falciparum in owl monkeys (Aotus sp.) but were ineffective at doses that were nontoxic."Antimicrob Agents Chemotherr 19883211 1655-993295442Pasloske, B. L. Baruch, D. I. van Schravendijk, M. R. Handunnetti, S. M. Aikawa, M. Fujioka, H. Taraschi, T. F. Gormley, J. A. Howard, R. J.Cloning and characterization of a Plasmodium falciparum gene encoding a novel high-molecular weight host membrane-associated protein, PfEMP3Amino Acid Sequence Animal Antibodies, Monoclonal Base Sequence Cloning, Molecular DNA, Protozoan/genetics Erythrocyte Membrane/parasitology *Genes, Protozoan Human Malaria, Falciparum/parasitology Membrane Proteins/chemistry/genetics/immunology Molecular Sequence Data Molecular Weight Peptide Fragments/genetics/immunology Plasmodium falciparum/*genetics Protozoan Proteins/chemistry/*genetics/immunology Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S.tnThe rat monoclonal antibody, mAb 12C11, reacts with numerous proteins from mature asexual stages of Plasmodium falciparum. The largest is 315 kDa and is designated PfEMP3. A lambda gt11 expression library, generated from genomic DNA of Malayan Camp strain parasites, was screened with mAb 12C11. One positive clone, lambda 12.1.3, contained a 1.4-kb fragment in frame with the beta-galactosidase gene of lambda gt11. The deduced 455-amino acid sequence is a novel, highly charged sequence encoding two 15-amino acid repeats at the N-terminus followed by 27 repeats of 13 amino acids. The last 59 C-terminal residues are non-repetitive. Two in-frame stop codons at the 3' end of the DNA suggests that this DNA fragment encodes the C-terminus of the protein. Southern blotting with the cloned fragment identified two copies of this fragment per haploid genome in knob-positive, parasitized erythrocytes (K+PE). Both DNA fragments are absent from K - PE. Northern blotting of trophozoite-stage PE total RNA revealed mRNAs of 10, 4.4 and 2 kb in K+PE, but no hybridization with K - PE. Immune sera were elicited against the lambda 12.1.3 beta-galactosidase fusion protein and peptides generated from the predicted lambda 12.1.3 amino acid sequence. These sera and mAb 12C11 reacted specifically with PfEMP3 in Western blots of mature K+PE but not with K - PE. Rat and mouse sera against the recombinant protein produced an immunofluorescence pattern in fixed mature K+PE almost identical to the pattern produced by a monoclonal antibody against the knob-associated protein, Histidine Rich Protein 1. The same antibodies were immunofluorescence negative with fixed K - PE. Mouse antibodies against the recombinant protein reacted on immunoelectron microscopy with the erythrocyte membrane of K+PE, labeling knobs as well as the membrane between knobs. In contrast, a mAb against Histidine Rich Protein 1 reacted only under the electron dense material of knobs. We conclude that the lambda 12.1.3 clone encodes the C-terminal portion of the 315 kD PfEMP3 antigen and that PfEMP3 may be involved in knob formation or other perturbations of the erythrocyte membrane.Mol Biochem Parasitol  1993591 59-72.JDPetersen, C. Nelson, R. Magowan, C. Wollish, W. Jensen, J. Leech, J.pjThe mature erythrocyte surface antigen of Plasmodium falciparum is not required for knobs or cytoadherenceMol Biochem Parasitol 1989361 61-5Q. AiZ |le, T. M. MyiZ P. T. Igarashi, I. Schoene, W. C.}iP@|kSchoene, W. |}0kin 1 gene, P|1, as a genetic marker. Four samples from primary attacks contained genetically mixed parasites harboring the 2 major PvMSP1 allelic forms. PCR revealed the pre`Zhttp://www.ncbi.nlm.nih.gov/cgi-bin/Entrez/referer?http://www.biomednet.com/article/he4212972616064-Oh, S. S. Chishti, A. H. Palek, J. Liu, S. C.eVOErythrocyte membrane alterations in Plasmodium falciparum malaria sequestrationAAnimal Erythrocyte Membrane/*pathology Erythrocytes/pathology/parasitology/ultrastructure Human Malaria, Falciparum/*blood/pathology *Plasmodium falciparum Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S.mPlasmodium falciparum malaria, the most lethal form of human malaria, claims at least 2 million lives worldwide each year. Recently, there has been a significant advance in our understanding of the molecular basis of P. falciparum sequestration, a distinctive pathologic feature that often leads to fatal human cerebral malaria. Parasite-derived VAR proteins (Plasmodium falciparum-infected erythrocyte membrane protein 1) have been cloned and identified as antigenically diverse cytoadherent receptors localized to the knob protrusions that act as attachment points in parasite sequestration. Evidence now supports the hypothesis that cryptic regions of band 3 protein are parasite-induced, host-derived erythrocyte receptors mediating parasite sequestration. Knob structures have been localized to spectrin-actin-protein 4.1 junctions in intact spread membrane skeletons. A recombinant domain of knob-associated histidine-rich protein, a major protein found in both membrane-intact and isolated knobs, has been shown to associate with filamentous actin and spectrin. Parasite- and host-derived erythrocyte membrane proteins involved in P. falciparum sequestration are discussed in this review.Curr Opin Hematol 19974 2 148-54IL4|3 Sharma, Y. D. Kilejian, A.F@Structure of the knob protein (KP) gene of Plasmodium falciparumMol Biochem Parasitol 198726 11-16 Ref11  Sharma, Y.D.2+Knob-associated histidine-rich protein gene* Nature 1987 326| 550 Ref1188225696 Sharma, Y. D.0leGenomic organization, structure and possible function of histidine-rich proteins of malaria parasitesAnimal *Genes, Structural Glycoproteins/*genetics Plasmodium/*genetics/physiology Plasmodium falciparum/*genetics/physiology Proteins/*genetics/physiology Support, Non-U.S. Gov'tThe current status of histidine-rich proteins in malaria parasites with regard to their genomic organization, protein structure and function is discussed, one of such protein present in an avian malaria parasite Plasmodium lophurae contains about 73% histidine and called as HRP (histidine-rich protein). Among human malaria parasites, in Plasmodium falciparum, only three such proteins have been described, namely knob protein also known as knob associated histidine-rich protein (KP or KAHRP), soluble histidine-alanine rich protein (soluble HARP or PfHRP II) and small histidine-alanine rich protein (SHARP) containing 8, 35 and 30% histidine contents respectively. With rapid emergence of powerful tools in molecular biology the genes of all these histidine- rich proteins have been cloned and sequenced within a short period of time. The genomic organizations of all these proteins are very much similar to each other, in each case the gene contains a signal peptide coding sequence (exon 1) followed by an intron. This intron is followed by the main coding region (exon 2) which has no further intervening sequences. In the main coding region of each gene, the histidine-rich sequences start after 25-30 amino acids from N-terminal end (75-90 nucleotides from 5' in exon 2). All the three histidine-rich proteins of P. falciparum share some homology with the HRP of P. lophurae; they all cross react with anti HRP and incorporate higher amount of exogenous histidine. The relationship between KP and HRP resides in the repeated polyhistidine sequences, (His) 6-9, from the core of the multiple tandem repeats of HRP, whereas, the peptide Ala-His-His is commonly shared by HRP and two other proteins of P. falciparum (soluble HARP and SHARP).(ABSTRACT TRUNCATED AT 250 WORDS) 1988 Int J Biochem`205 471-7 Using Smart Source Parsing91330572 Sharma, Y. D.3haMalaria and Leishmania parasites share the knob-associated histidine- rich protein gene sequences Animal Deoxyribonuclease EcoRI DNA, Protozoan/genetics Histidine/*genetics Leishmania donovani/*genetics Nucleic Acid Hybridization Peptides/*genetics Plasmodium falciparum/*genetics Protozoan Proteins/*genetics Sequence Homology, Nucleic Acid Support, Non-U.S. Gov'tg1. The main coding region of the knob-associated histidine-rich protein (KAHRP) gene of Plasmodium falciparum hydridized with genomic DNA of Leishmania donovani. 2. A total of five EcoRI fragments of various sizes (7.5, 5.5, 3.2, 0.75 and 0.56 Kb) were recognized by this probe, under lower stringent conditions. However, under a higher stringency of washing, two of the smallest fragments were washed away. 3. Out of these EcoRI fragments, the 5.5 Kb band showed a maximum homology with the probe which contains the histidine-rich coding sequences, whereas the 3.2 Kb band showed none. Thus there is a possibility that the Leishmania parasite also contains a KAHRP-like gene. 1991Comp Biochem Physiol [B]984 433-5  Using Smart Source ParsingVZZ@W94035310el-Shoura, S. M.Falciparum malaria in naturally infected human patients: ultrastructural alterations of non-parasitized red blood cells during anaemiaAcute Disease Adolescence Adult Anemia, Hemolytic/blood/*etiology Child Child, Preschool Erythrocytes/*ultrastructure Human Malaria, Falciparum/*blood/complications Male Microscopy, Electron Middle Aget,&Several ultrastructural alterations have been displayed by non- parasitized erythroblasts (Eb) and erythrocytes (Ec) in the peripheral blood of 28 Saudi patients who were anaemic and suffering from acute falciparum malaria (AFM). A counting system is incorporated to determine the rate of altered to normal red cells in plastic serial sections. The Eb showed for the first time conspicuous surface knobs which were previously described only for parasitized Ec, and are known to play a role in their adhesion to vascular endothelial cells. The Ec displayed a bizarre contour and ragged appearance produced by the abundance of cytoplasmic processes. Such cells were similar to erythrocytic ropalocytes seen in haematological diseases associated with anaemia. The Ec also possessed autolysosome-like vacuoles containing rosette forms of alpha-glycogen-like particles (GLP) while smaller beta-GLP were dispersed in the cytoplasm. Ultrastructural alterations of these cells were suggested to be due to dyserythropoiesis and ineffective erythropoiesis, which were in turn attributed to an unbalance in metabolism as they were being overproduced in response to infection. Numerous haemoglobin-like particles (Hg) were being liberated through the erythrocytes plasma membranes indicating severe haemolysis which is considered to be one of the major factors in producing anaemia during malarial infection. This study showed tat anaemia is common in patients with AFM which is usually associated with structural alterations of non-parasitized immature and mature red blood cells (RBC). In addition, the rate of abnormal RBC correlates with the degree of parasitaemia. Moreover, old patients showed a lower degree of parasitaemia than young patients, possibly due to a less mature immune system in the later.(ABSTRACT TRUNCATED AT 250 WORDS)Appl Parasitol 1993343  173-9r93210767& el-Shoura, S. M. al-Amari, O. M.Falciparum malaria in naturally infected human patients: II. Ultrastructural alterations to erythrocytes infected with asexual formsAnimal Comparative Study Erythrocytes/parasitology/*ultrastructure Human Malaria, Falciparum/*pathology Microscopy, Electron Plasmodium falciparum/physiology/ultrastructure Species Specificity{Ultrastructural alterations of human erythrocytes infected with asexual forms of Plasmodium falciparum were studied in naturally infected Saudi patients. These included surface knobs and nodules as well as invaginations associated with cytoplasmic vesicles observed in erythrocytes infected with asexual forms of the parasites. Such nodules and surface invaginations have been previously described only in erythrocytes infected with P. ovale and P. vivax, respectively. Within the cytoplasm of infected erythrocytes were membrane-bound clefts, similar to those that appear to be a common characteristic in all red cells infected with malaria parasites. Vacuolations were often seen in the peripheral cytoplasm and may represent hemolyzed areas. Collapsed cells with an internal-lucent interior and surrounded by an irregularly folded membrane may represent completely hemolyzed erythrocytes.  J Morphol 1993 215b3@ 207-12HAEllis, J. Irving, D. O. Wellems, T. E. Howard, R. J. Cross, G. A. 1987f_Structure and expression of the knob-associated histidine-rich protein of Plasmodium falciparumAMol Biochem Parasitol26203-214 0850 Ref11 94265892d]Fujioka, H. Millet, P. Maeno, Y. Nakazawa, S. Ito, Y. Howard, R. J. Collins, W. E. Aikawa, M.zsA nonhuman primate model for human cerebral malaria: rhesus monkeys experimentally infected with Plasmodium fragileAnimal Antigens, CD/analysis Brain/*parasitology/ultrastructure Cell Adhesion Molecules/analysis *Disease Models, Animal Erythrocytes/parasitology/ultrastructure Immunohistochemistry Macaca mulatta/*parasitology Malaria, Cerebral/blood/*parasitology Membrane Glycoproteins/analysis Plasmodium/*physiology Receptors, Cytoadhesin/analysis Rosette Formation Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S.vpWe studied the brains of rhesus monkeys infected with the primate malaria parasite Plasmodium fragile. Electron microscopy showed that, in these animals, erythrocytes infected with P. fragile undergo sequestration and that parasitized red blood cells adhere to endothelial cells in the cerebral microvessels by means of knobs. Cerebral microvessels with sequestered parasitized red blood cells were shown by immunohistochemical analysis to possess the platelet glycoprotein CD36, thrombospondin, and intracellular adhesion molecule- 1. The formation of rosettes also was observed in the cerebral microvessels. In a fashion similar to human cerebral malaria, P. fragile produced neurological symptoms in the animals. Thus, rhesus monkeys infected with P. fragile, like those monkeys infected with Plasmodium coatneyi, can be used as a primate model to study human cerebral malaria. Exp Parasitol  1994784 371-6i&Gritzmacher, C. A. Reese, R. T.  1984PIReversal of knob formation on Plasmodium falciparum-infected erythrocytesScience 226 65-67 0899 Ref112.10*T 85216585@9Raventos-Suarez, C. Kaul, D. K. Macaluso, F. Nagel, R. L.~wMembrane knobs are required for the microcirculatory obstruction induced by Plasmodium falciparum-infected erythrocytes5Blood Viscosity Erythrocytes/*pathology Hemodynamics Human Malaria/*blood *Microcirculation Microscopy, Electron Plasmodium falciparum Regional Blood Flow Support, U.S. Gov't, P.H.S.F@We have studied the pathophysiology of the vascular obstruction induced by Plasmodium falciparum-parasitized erythrocytes with the use of an ex vivo microcirculatory preparation perfused with red cells infected with knobless and knobby clones of the FCR-3 strain. We find that parasitized erythrocyte membrane knobs are indispensable for the generation of the circulatory obstruction. Uninfected erythrocytes incubated in culture and erythrocytes infected with early or late forms of the knobless clones or the early forms of the knobby clone all failed to obstruct the microcirculation, although exhibiting various effects on bulk viscosity and peripheral resistance during flow. In contrast, late forms of the knobby clone produced significantly higher peripheral resistance during flow and significant obstruction as detected by changes in time of pressure flow recovery as well as by direct videorecorded microscopic observation. Optical and electron microscopy showed that the adherence of parasitized cells to the endothelium was limited to the venules and involved the knobs in junctions. In addition, we were able to follow the sequence of events during obstruction: initial red-cell adherence to the venular endothelium (sometimes only transitory) followed by progressive recruitment at the venule surface, finally leading to total obstruction that involved parasitized and nonparasitized erythrocytes. Sometimes, retrograde aggregation would extend the obstruction to the capillaries or even precapillary arterioles. These results show that knobs are necessary and sufficient to produce vascular obstruction and that other factors (spleen, immunological, etc.) can only have a modulating role. These results also exclude the possibility that the exclusive adherence to venules is the consequence of "plasma factors" found in the malaric patients.Proc Natl Acad Sci U S A 198582113829-3396205004BUltrastructure of malaria-infected erythrocytes [see comments]Animal Erythrocytes/*parasitology/ultrastructure Human Malaria/*blood/parasitology Microscopy, Electron Plasmodium/physiology/ultrastructure Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S.Knobs, caveolae, caveola-vesicle complexes, cytoplasmic clefts, and electron-dense material are five major ultrastructural changes found in the membrane skeleton and cytoplasm of erythrocytes infected with species of primate malaria. Knobs are electron-dense, conical evaginations of the erythrocyte surface, which are believed to mediate cytoadherence and sequestration of Plasmodium falciparum-infected erythrocytes. Caveolae and caveola-vesicle complexes are flask-shaped invaginations of the membrane skeleton, which may be involved in the uptake or export of host- or parasite-derived substances. Cytoplasmic clefts are flattened or circular membranous structures found in the erythrocyte cytoplasm between the intracellular parasite and the host cell surface. The clefts are variable in length and bounded by two or more membranes. Fine, granular electron-dense material is often found on the cytoplasmic face of clefts or in amorphous packets in the erythrocyte cytoplasm. Immunocytochemistry has demonstrated that all of these ultrastructural changes are associated with the trafficking and interaction of specific malarial antigens with the host erythrocyte.e 1990 Blood Cellsc16 2-3 351-68 Using Smart Source ParsingF?Biggs, B. A. Culvenor, J. G. Ng, J. S. Kemp, D. J. Brown, G. V.m>8Plasmodium falciparum: cytoadherence of a knobless clone Exp Parasitoln 198969 189]189-197zsBiggs, B. A. Gooz, L. Wycherley, K. Wilkinson, D. Boyd, A. W. Forsyth, K. P. Edelman, L. Brown, G. V. Leech, J. H./leKnob-independent cytoadherence of Plasmodium falciparum to the leukocyte differentiation antigen CD36 J Exp Med 1990 1716 1883-189294136012ngBonnefoy, S. Gysin, J. Blisnick, T. Guillotte, M. Carcy, B. Pereira da Silva, L. Mercereau-Puijalon, O.Immunogenicity and antigenicity of a Plasmodium falciparum protein fraction (90-110 kDa) able to protect squirrel monkeys against asexual blood stagesNHAnimal Antibodies, Protozoan/biosynthesis Blotting, Western Electrophoresis, Polyacrylamide Gel Enzyme-Linked Immunosorbent Assay Heat-Shock Proteins/immunology Malaria Vaccines/*immunology Plasmodium falciparum/*immunology Precipitin Tests Protozoan Proteins/*immunology/isolation & purification Saimiri Support, Non-U.S. Gov'tA monkey vaccination trial using a Plasmodium falciparum protein fraction containing antigens of 90-110 kDa is reported. The fraction was obtained by electroelution from preparative polyacrylamide gels. Three monkeys out of five resisted a heavy challenge dose of highly virulent parasites. Using specific antisera, several components of the fraction were identified, namely heat shock protein 90 (hsp90), Ag44/RhopH3, ABRA, 96tR/GBP130 and Pf96 protease. The fraction did not contain KAHRP, nor the SERP antigen. The antibody response of the monkeys was studied on these individual antigens purified by preparative immunoprecipitation. Surprisingly, hsp90 was found in the immunoprecipitates obtained with SERP antisera. Interestingly, the response to hsp90 correlated with protection, high antibody titres being found only in the protected monkeys. In contrast, no correlation with protection could be found for the response to the other antigens.Vaccine 1994121 32-40S[85248814TMMacPherson, G. G. Warrell, M. J. White, N. J. Looareesuwan, S. Warrell, D. A.anhHuman cerebral malaria. A quantitative ultrastructural analysis of parasitized erythrocyte sequestrationAdolescence Adult Brain Diseases/*parasitology Erythrocytes/*parasitology/ultrastructure Female Heart/parasitology Human Liver/parasitology Lung/parasitology Malaria/*parasitology Male Plasmodium falciparum/isolation & purification Support, Non-U.S. Gov'tdFor investigation of the pathogenesis of cerebral malaria, immediate postmortem samples from brain and other tissues of patients dying with Plasmodium falciparum malaria, with (CM) or without (NCM) cerebral malaria, were processed for electron microscopy. Counts of parasitized erythrocytes (PRBCs) in cerebral and other vessels showed that the proportion of PRBCs was higher in CM than in NCM, and also that the proportion of PRBCs was higher in the brain than in other organs examined in both CM and NCM. Cerebral vessels from CM patients were more tightly packed with RBCs than those from NCM patients, but there was no significant difference in the amount or degree of endothelial damage or numbers of vessels with endothelial pseudopodia. Fibrillar (fibrin) deposits were present in a small proportion of vessels, but no thrombosis was present. There was neither acute nor chronic inflammation, and leukocytes were absent within or outside cerebral vessels. There was no immune complex deposition in cerebral vessels. Parasites in cerebral vessels were mainly trophozoites or schizonts. Occasional RBC remnants following parasite release were seen. Some parasites were degenerate, resembling crisis forms. PRBCs adhered to endothelium via surface knobs. It is concluded that there is no evidence for an inflammatory or immune pathogenesis for human cerebral malaria and that the clinical effects probably relate to anoxia and the metabolic activities of the parasites.X Am J Patholm 1985 1193385-401 83176128 Motyl, M. R. Reese, R. T.`ZTPlasmodium falciparum: comparison of in vitro growth of knobby and knobless isolatesAnimal Aotus trivirgatus Comparative Study Immune Sera/pharmacology In Vitro Isoleucine/metabolism Malaria/parasitology Plasmodium falciparum/drug effects/*growth & development/isolation & purification Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S.p<5Variants (K-) of three strains of Plasmodium falciparum which do not produce the erythrocyte surface alterations that have been called knobs have been compared with their wildtype knobby (K+) parents. The K- variants achieve higher parasitemias, incorporate radiolabeled isoleucine more rapidly, and produce a higher percentage of multiply- infected cells than do their K+ parents. Nevertheless, immune owl monkey sera cause approximately the same percentage inhibition of growth of both K+ and K- organisms when included in the growth medium at a 1% concentration. Am J Trop Med Hygm 1983322  226-3092372980D=Nakamura, K. Hasler, T. Morehead, K. Howard, R. J. Aikawa, M.Plasmodium falciparum-infected erythrocyte receptor(s) for CD36 and thrombospondin are restricted to knobs on the erythrocyte surface\VAffinity Labels Animal Antigens, CD/*metabolism Erythrocytes/metabolism/pathology/*parasitology Malaria, Cerebral/pathology Microscopy, Electron Plasmodium falciparum/*metabolism Platelet Membrane Glycoproteins/*metabolism Receptors, Cell Surface/*metabolism Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S.piAdherence of Plasmodium falciparum-infected RBCs (PRBC) to endothelial cells causes PRBC sequestration in cerebral microvessels and is considered to be a major contributor to the pathogenesis of cerebral malaria. Both CD36 and thrombospondin (TSP) are glycoproteins that mediate PRBC adherence to endothelial cells in vitro. Because they are both expressed on the surface of endothelial cells, they probably contribute to PRBC sequestration and vascular occlusion in vivo. By applying affinity labeling of receptor binding sites with purified ligands, we showed for the first time that both CD36 and TSP can bind independently to the PRBC surface and that the PRBC receptor(s) for CD36 and TSP are localized specifically to the electron-dense knob protrusions of the PRBC surface. These findings may help in efforts to develop a malaria vaccine to prevent cerebral malaria.J Histochem Cytochem 19924091419-2296439808\VNakano, Y. Fujioka, H. Luc, K. D. Rabbege, J. R. Todd, G. D. Collins, W. E. Aikawa, M.A correlation of the sequestration rate of Plasmodium coatneyi-infected erythrocytes in cerebral and subcutaneous tissues of a rhesus monkey Animal Brain/blood supply/*parasitology Erythrocytes/*parasitology Macaca mulatta Malaria, Cerebral/*parasitology Microcirculation/parasitology Plasmodium/*physiology Skin/blood supply/*parasitology Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S.~xParasitized red blood cells (PRBCs) were sequestered in microvessels of cerebral and subcutaneous tissues of a rhesus monkey infected with Plasmodium coatneyi. A similar sequestration rate (approximately 80%) was observed in both cerebral and subcutaneous microvessels. Electron microscopy showed knobs of the sequestrated PRBCs cytoadhered to endothelial cells. These results are consistent with the finding of PRBC sequestration in subcutaneous tissues in a comatose patient with cerebral malaria. Biopsy specimens of subcutaneous tissue may be useful as indicators of PRBC sequestration in the brain of cerebral malaria patients.Am J Trop Med HygJ 1996553 311-4kF.n8828575060Janoff, A. Roth, W. J. Sinha, S. Barnwell, J. W.F?Degradation of plasmodial antigens by human neutrophil elastase.Amino Acid Sequence Animal Antigens, Protozoan/isolation & purification/*metabolism Antigens, Surface/isolation & purification/metabolism Cathepsins/pharmacology Erythrocytes/parasitology Human Macrophages/immunology Molecular Sequence Data Neutrophils/*enzymology/parasitology Oligopeptides/isolation & purification Pancreatopeptidase/*physiology Peptide Hydrolases Plasmodium vivax/*immunology Receptors, Fc/drug effects Repetitive Sequences, Nucleic Acid Rosette Formation Support, U.S. Gov't, P.H.S.nHuman neutrophil elastase (HNE) has been well-studied with respect to its role in pathologic states, but less is known about the physiologic functions of this important granulocyte enzyme. In the present study, we show that HNE can degrade the major circumsporozoite protein of the infective (sporozoite) stage of Plasmodium vivax malaria, and that this enzyme can also interfere with the cytoadherence of human E infected with Plasmodium falciparum (strain K+ FMG-FCR3) (IE). Cytoadherence reactions are not only blocked by treatment of IE with as little as 10 fg HNE/IE, but already adherent IE are also removed by the enzyme. Normal E surface Ag are not extensively destroyed by these doses of HNE. This suggests that the effect of HNE on cytoadherence is selective and probably due to degradation of the malarial Ag exported to the IE surface and responsible for the formation of "recognition knobs" upon which the cytoadherence reaction depends. This conclusion, in turn, was supported by the results of Western blot analysis showing that HNE degrades a high m.w. Ag found exclusively in membrane extracts of IE. Our results suggest that one physiologic role of HNE may be degradation of parasitic antigens during host defense against malaria. J Immunol@ 1988 141`4 1332-40e96181686Kant, R. Sharma, Y. D.`YAllelic forms of the knob associated histidine-rich protein gene of Plasmodium falciparum.tm*Alleles Amino Acid Sequence Animal Base Sequence Cloning, Molecular Genes, Structural, Protozoan/*genetics Human India Molecular Sequence Data Peptides/*genetics Plasmodium falciparum/*genetics Protozoan Proteins/*genetics Repetitive Sequences, Nucleic Acid/genetics Sequence Analysis, DNA Sequence Homology, Amino Acid Support, Non-U.S. Gov't Variation (Genetics)oThe knob associated histidine-rich protein (KAHRP) gene was cloned and sequenced from two Indian isolates of Plasmodium falciparum, Pf3-92 and Pf29-92. These isolates showed major sequence differences in the C- terminal repeat domain of KAHRP. However, the biologically important domains such as spectrin-actin binding region remained highly conserved. The PCR amplification of a variable C-terminal repeat domain from the clinical isolates of P. falciparum, from Rajasthan epidemic, showed the presence of multiple alleles of KAHRP gene. The presence of multiple alleles indicates the existence of several P. falciparum strains in India. This should be taken into account for future malaria control strategies such as molecular therapy and vaccines. FEBS Lett 1996 380t 1-2 147-51|86285000"Pologe, L. G. Ravetch, J. V.ztA chromosomal rearrangement in a P. falciparum histidine-rich protein gene is associated with the knobless phenotypeChromosome Mapping DNA/genetics DNA Restriction Enzymes Human Mutation Peptides/*genetics Phenotype Plasmodium falciparum/*genetics Proteins/*genetics *Recombination, Genetic Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S.The significant morbidity and mortality associated with Plasmodium falciparum malaria results, in part, from the sequestration of parasitized erythrocytes in postcapillary venules, which may protect the parasite from splenic clearance and contribute to the pathogenesis of cerebral malaria. This sequestration has been linked to the expression of parasite-induced knob structures on the surface of the infected erythrocyte which mediate the cytoadherence phenomenon. While knobs are necessary for cytoadherence, they are not sufficient, requiring both parasite- and host-encoded proteins. Spontaneous mutants of P. falciparum have been isolated from in vitro cultures which lack the ability to express knobs and fail to cytoadhere. A histidine-rich protein has been described which is associated with the knobby phenotype and may be a constituent of the knob. We now report the isolation of complementary DNA clones for a knob-associated histidine- rich protein (KAHRP) and demonstrate that in knobless mutants the gene for this protein has undergone a rearrangement, resulting in a deletion in the 3' coding sequence. Moreover, the chromosome to which the KAHRP gene maps is rearranged in these mutants, producing a telomeric location of the truncated gene. These observations explain the loss of expression of the messenger RNA and protein in such mutants and may explain the loss of the knob itself. The implications for the generation of spontaneous mutations in the parasite by this novel mechanism are discussed. Nature 1986 322. 6078 474-7ajfjq88162894@:Lenstra, R. Samso, A. Andrieu, B. Le Bras, J. Galibert, F.Viruslike particles containing knob-associated histidine-rich protein are secreted into the culture medium of Plasmodium falciparum in vitro cultures.Animal Culture Media Erythrocytes/parasitology/ultrastructure Human Malaria/blood Microscopy, Electron Plasmodium falciparum/*metabolism/microbiology Proteins/biosynthesis/*isolation & purification Reference Values Support, Non-U.S. Gov't Viruses/*isolation & purificationHAThis report describes the isolation of a viruslike particle from in vitro cultures of the human malaria parasite P. falciparum. Electronmicroscopic observations suggest that the particles are liberated into the culture medium by budding from the erythrocyte membrane. The density of the free particles is 1.16, they contain nucleic acid and two distinct molecular species of the knob-associated Histidine-rich protein. Proteins of the particles are recognized by sera from malaria patients. The previously described knobs may correspond to viral coats inserted in the membrane.r Biochem Biophys Res Commun 1988 1512e 749-57900267074.Mackenstedt, U. Mehlhorn, H. Brockelman, C. R.jdUltrastructural study on the interaction of beta-thalassemic- erythrocytes and Plasmodium falciparumAnimal Erythrocytes/*parasitology/ultrastructure Host-Parasite Relations Human Malaria/blood/*complications Microscopy, Electron Plasmodium falciparum/*physiology/ultrastructure Support, Non-U.S. Gov't Thalassemia/blood/*complicationsbeta-thalassemic erythrocytes and normal red blood cells were experimentally infected in vitro with Plasmodium falciparum cultured for 4 days and studied by means of transmission electron microscopy. Conspicuous alterations of the parasites appear in the advanced stage of schizogony leading to the fact that only a small amount of malaria pigment is formed, which in general is not crystalline, but always enclosed in extremely large vacuoles. Furthermore some of the developing merozoites reveal features of cellular degeneration, thus these merozoites lost their ability to invade new erythrocytes. Despite these findings alterations of the host cells are induced by the parasites, which, however, are comparable to those found in infected normal red blood cells, e.g. knobs appeared on the surface of the erythrocytes and membrane-bounded clefts became apparent in the cytoplasm of the host cell.Zentralbl Bakteriole 1989 2713 356-6389367226@:Mackenstedt, U. Brockelman, C. R. Mehlhorn, H. Raether, W.`YComparative morphology of human and animal malaria parasites. I. Host- parasite interface.|Animal Chickens Comparative Study Erythrocytes/*parasitology/ultrastructure Host-Parasite Relations Human Malaria/*parasitology Mice Microscopy, Electron Plasmodium/*ultrastructure Plasmodium berghei/ultrastructure Plasmodium falciparum/ultrastructure Plasmodium gallinaceum/ultrastructure Plasmodium malariae/ultrastructure Plasmodium vivax/ultrastructure Support, Non-U.S. Gov'ttnHuman and animal malaria parasites (Plasmodium falciparum, P. malariae, P. vivax, P. berghei, P. gallinaceum) were studied using special fixation and standardized methods, with special attention to their effects on host cells. Morphological alterations induced by the parasites in infected erythrocytes included knobs, invaginations, and caveola-vesicle complexes on the surface of the host cell and clefts, microvesicles, and small vesicles in the cytoplasm of the infected erythrocytes. For P. malariae, the ultrastructural study revealed invaginations with associated microvesicles, but knobs did not occur on the surface of infected erythrocytes. The development of invaginations and microvesicles in P. malariae-infected erythrocytes corresponded to the morphological alterations induced by P. vivax. A new hypothesis concerning the origin of Schuffner's dots is discussed. 1989 Parasitol Res 757 528-35 Using Smart Source Parsing^ RdBrpn88292557 Aikawa, M.Human cerebral malariaAdolescence Adult Animal Brain/blood supply/pathology Brain Diseases/blood/*etiology/pathology/parasitology Capillaries Cell Adhesion Child Child, Preschool Erythrocytes/parasitology/ultrastructure Female Human Immunoenzyme Techniques Immunohistochemistry Malaria/blood/*etiology/pathology/parasitology Male Membrane Proteins/analysis Microscopy, Electron Microscopy, Electron, Scanning Middle Age Peptides/analysis Plasmodium falciparum/ultrastructure Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S.Possible factors contributing to the development of cerebral malaria were discussed based on pathological changes in Burmese patients who died of cerebral malaria. Blockage of cerebral capillaries by Plasmodium falciparum infected erythrocytes appeared to be the principal cause of cerebral malaria. From electron microscopic results, it was concluded that knobs on infected erythrocytes acted as focal junctions which mediated adhesion to endothelial cells. The knobs are, therefore, important contributors to the blockage of the capillary lumen and ensuing pathological changes in cerebral tissues. Host cell molecules such as OKM5 and thrombospondin may function as endothelial cell surface receptors for the attachment of knobs of P. falciparum infected erythrocytes. Immunological events might also play a role in the pathogenesis of cerebral malaria. This was suggested by the presence of IgG, IgM, P. falciparum antigens, and knob proteins in the cerebral capillaries of the people with cerebral malaria. It will be important to assess the candidate malaria vaccines now in development not only for their efficacy in reducing parasitemia but for effects they may have on the sequestration of infected erythrocytes in the brain.Am J Trop Med Hyg 1988391 3-1089150732 Aikawa, M.JCMorphological changes in erythrocytes induced by malarial parasites9Animal Erythrocytes/parasitology/*ultrastructure Host-Parasite Relations Human Microscopy, Electron Plasmodium/*physiology Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S.& Host cell alterations induced by Plasmodium falciparum, P. brasilianum, P. vivax and P. malariae were described by electron microscopy and post- embedding immunoelectron microscopy. P. falciparum infection induces knobs, electron-dense material and clefts in the erythrocyte. Clefts are involved in exporting P. falciparum antigen from the parasite to the erythrocyte membrane. P. falciparum antigen is present in knobs which adhere to endothelial cells causing the blockage of cerebral capillaries and ensuing pathological changes in cerebral tissues. P. brasilianum infection induces knobs, short and long clefts and electron- dense material. These structures appear to contain different P. brasilianum antigens. This indicates that each structure functions independently in trafficking P. brasilianum protein to the erythrocyte surface. P. vivax infection induces caveola-vesicle complexes and clefts in the erythrocyte. These structures are also involved in trafficking P. vivax protein from the parasite to the erythrocyte membrane. P. malariae induces caveolae, electron-dense material, vesicles, clefts and knobs in the erythrocyte. Although vesicles and caveolae are seen in the erythrocyte cytoplasm, they do not form caveola-vesicle complexes as seen in P. vivax-infected erythrocytes. They also appear to be involved in trafficking of malaria antigens. These studies, therefore, indicate that host cell changes occur in order to facilitate the transport of malarial antigens to the host cell membrane. The significance of these phenomena is still not clear. 1988 Biol Cell642 173-81 Using Smart Source Parsing90358307NGAikawa, M. Iseki, M. Barnwell, J. W. Taylor, D. Oo, M. M. Howard, R. J..'The pathology of human cerebral malariaBAnimal Brain/*blood supply/ultrastructure Brain Diseases/*pathology Cell Adhesion Human Malaria/*pathology Microcirculation Microscopy, Electron Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S.Blockage of the cerebral microvasculature by Plasmodium falciparum- infected erythrocytes appears to be the principal cause of human cerebral malaria. Knobs which appear on the membrane of the infected erythrocytes adhere to the endothelium, causing the obstruction of cerebral microvessels. Protein molecules such as CD36, thrombospondin, and intercellular adhesion molecule-1, which are present on the membrane of endothelial cells, may act as receptors for the attachment of knobs of P. falciparum-infected erythrocytes. Each of these candidate host molecules for infected-cell recognition and attachment are expressed in microvessels of the human brain. The presence of HRP1 and HRP2 in the cerebral microvessels of cerebral malaria patients may indicate the involvement of knob proteins in the pathogenesis of cerebral malaria. Owl monkeys infected with P. falciparum do not develop cerebral malaria. There is no blockage of cerebral microvessels by infected erythrocytes and knob proteins are absent. These findings support the contention that cerebral microvessel blockage and the presence of knob proteins are the probable causes of cerebral malaria.Am J Trop Med Hyg 199043 2 Pt 2 30-792246249|vAikawa, M. Brown, A. Smith, C. D. Tegoshi, T. Howard, R. J. Hasler, T. H. Ito, Y. Perry, G. Collins, W. E. Webster, K.^XA primate model for human cerebral malaria: Plasmodium coatneyi- infected rhesus monkeys*#Animal Antigens, CD/analysis Brain/blood supply Cell Adhesion Cell Adhesion Molecules/analysis *Disease Models, Animal Endothelium, Vascular/*metabolism/ultrastructure Erythrocytes/*metabolism/parasitology/ultrastructure Fluorescent Antibody Technique Immunohistochemistry Macaca mulatta/*parasitology Malaria, Cerebral/*blood/parasitology Microcirculation Microscopy, Electron Platelet Membrane Glycoproteins/analysis Receptors, Cell Surface/analysis Splenectomy Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S.oA major factor in the pathogenesis of human cerebral malaria is blockage of cerebral microvessels by the sequestration of parasitized human red blood cells (PRBC). In vitro studies indicate that sequestration of PRBC in the microvessels is mediated by the attachment of knobs on PRBC to receptors on the endothelial cell surface such as CD36, thrombospondin (TSP), and intercellular adhesion molecule-1 (ICAM- 1). However, it is difficult to test this theory in vivo because fresh human brain tissues from cerebral malarial autopsy cases are not easy to obtain. Although several animal models for human cerebral malaria have been proposed, none have shown pathologic findings that are similar to those seen in humans. In order to develop an animal model for human cerebral malaria, we studied brains of rhesus monkeys infected with the primate malaria parasite, Plasmodium coatneyi. Our study demonstrated PRBC sequestration and cytoadherence of knobs on PRBC to endothelial cells in the cerebral microvessels of these monkeys. Cerebral microvessels with sequestered PRBC were shown by immunohistochemical analysis to possess CD36, TSP, and ICAM-1. These proteins were not evident in the cerebral microvessels of uninfected control monkeys. Thus, our study indicates, for the first time, that rhesus monkeys infected with P. coatneyi can be used as a primate model to study human cerebral malaria. By using this animal model, we may be able to evaluate strategies for the development of vaccines to prevent human cerebral malaria.Am J Trop Med Hyg 1992464 391-7& Abati19771Afzelius1991o Aikawa198112 Aikawa19822 Aikawa19833 Aikawa19848 Aikawa19879 Aikawa198779 Aikawa19877u Aikawa19878w Aikawa19878y Aikawa1987m Aikawa19889o Aikawa1988p Aikawa1988r Aikawa19888h Aikawa1989cd Aikawa19901e Aikawa19909 Aikawa19919[ Aikawa19929^ Aikawa1992a_ Aikawa1992a Aikawa1992X Aikawa19939Y Aikawa1993V Aikawa19944R Aikawa19967S Aikawa19966N Aikawa19978 Aji1991Zal-Amari19933 Aley19849 Aley19878w Aley19878< Allen1982< Allen1982 Allred19839} Allred19866 Anders19877 Anders19878\ Andrabi1992iAndrade Junior1989+q Andrieu1988u Andrysiak1987Ardeshir1987R Arwati19969uAtkinson1987@eAtkinson1990y Aye1987] Bannister19922Barnwell1982Barnwell1984@nBarnwell19888dBarnwell1990Y Baruch19939 Beale1984h Berzins19891 Berzins1991 Biggs1989 Biggs1990HBlisnick1994 HBonnefoy1994  Boyd1990KBrewster1990Zf Brockelman19899j Brockelman19899 Brown1987 Brown1987 Brown1989 Brown1990b Brown1991^ Brown1992_ Brown1992D Brown1997uCampbell19877H Carcy1994K Carlson1990D Caruana1997 Chalvet19989 Chapman1987\ Chishti1992Q Chishti1997oCochrane19888Cochrane19908aCochrane19929m Cohen1988u Collins1987^ Collins1992_ Collins1992V Collins1994S Collins1996D Cooke1997 Coppel19878D Coppel19977i Corbett1989D Cowman19977t Cox1987D Crabb1997`Crandall1992 Crewther1987 Crewther1987 Cross1987 Culvenor1987Culvenor19897 Daniel19833D Davern19977Gde Bruin19949l de la Vega1988+\ Derick19922 Dixit1985i Duarte19899 Edelman1990W el-Shoura1993Z el-Shoura1993 Ellis1987m Escajadillo1988w et al.19878 Fandeur1998 Fenton19849 Flint1987 Forsyth1990 Frazier1985Y Fujioka1993V Fujioka1994S Fujioka1996qGalibert19889T Gay-Andrieu1996Ginsburg19855 Gooz1990Y Gormley1993 Green19812 Green1982 Green1983x Greenan1987l Greenan1988K Greenwood1990 Gritzmacher1984 Gruenberg1983 Gruenberg1983} Gruenberg1986 Gubert19811H Guillotte1994: Guo1989H Gysin1994T Gysin1996 Hadley19833Y Handunnetti1993~ Harvey19869[ Hasler19929^ Hasler19922_ Hasler199222 Hay1982AHeidrich1984d@Heidrich1985K Helmby19900K Hill19909EHirawake1997] Ho1992(t Hommel19877 Howard19838 Howard19848 Howard19848 Howard19859~ Howard19869 Howard198779 Howard19877u Howard19877w Howard198770 Howard198887 Howard19889m Howard19889d Howard19909[ Howard19929^ Howard19922_ Howard19922Y Howard19933V Howard19949v Hughes19877Igarashi19873yIgarashi1987Z Irving19878d Iseki1990^ Ito1992_ Ito1992V Ito1994R Ito1996n Janoff19889 Jensen19787 Jensen19838* Jensen19899RKamanura1996 o Kamboj19889: Kamboj19899X Kano19939U Kano19955F Kant1996{ Karoui19868 Kaul19858 Kaul1985SX Kawai1993U Kawai1995 Kemp19878 Kemp19878 Kemp19891Kilejian19773Kilejian19793Kilejian19803Kilejian19833 Kilejian19843Kilejian1985n{Kilejian1986@3Kilejian1987Kilejian19888Kilejian19908 Kilejian19908 Kilejian19918$Kilejian19913m Kirk19888E Kita19971w Klotz1987m Labroo19889i Lancellotti1989 Langford1987Langreth1978@%Langreth19793Langreth1979@=Langreth19831Langreth1985 Lanners1981= Lanners1983= Lanners198381= Lanners1983= Lanners1983= Lanners1983= Lanners1983= Lanners198381= Lanners1983= Lanners1983= Lanners1983= Lanners198381= Lanners198381= Lanners1983= Lanners198381= Lanners1983= Lanners198381= Lanners1983= Lanners1983= Lanners1983= Lanners1983= Lanners198381= Lanners198381= Lanners198381= Lanners1983= Lanners1983= Lanners1983= Lanners1983= Lanners1983= Lanners1983= Lanners1983= Lanners1983er19969QKremsner199790Kremsner1999 Krettli1992( Krettli1999EKrogstad199883 Kulachelvy19999 Kumar1992 Kumar1994 Kumar1995 Kumar1996 Kumar1997 Kumar1997 Kumar1998, Kurtzhals1999Kusumoto1991\ Kyes1997 Lainson1991u Lal1995e Lal1996L Lal1998O Lal1998S Lal1998> Lal1999) Lalitha1999( Lambert1986GLangford1986nqLangford1988Langford1989Langford1989!n <d n1986q Brown1988 Brown1988 Brown1989 Brown1991 Brown1991 Brown1992 Brown1993 Brown1993 Brown1993t Brown1995 Brown1995 Brown1996 Brunet19868O Bujard1985r Bujard19881 Bujard1989 Bujard19898 Bujard19909 Bujard19919 Bujard19919 Bujard1992J Bujard19933 Bujard1995[ Bujard199797 Bujard19991#Buranakitjaroen19874 Buratti1999Burghaus1992Burghaus1994Burghaus1994Burghaus1995<%Burghaus1995hBurghaus19966/Burghaus19999 Burki1990{ Burns1988 Burns1988 Burns1989 Burns1989 Burns1989 Burns1992 Bustos19933 Cabezas1987= Cachay1998+o Calvo19968 Calvo1998H Calvo1998 Camargo1992 Camargo1992 Camargo1993 Camargo1994@Campbell1985 Camus1987 Camus1987f Candito1996U Carter19800 Carter19888 Carter19888 Carter1990s Carter1990s88 Carter1990s88 Carter1990s been shown to induce immunity against every one of these parasite stages against which vaccines are being developed, an exception to this are those stages that are present only in the mosquito vector with component molecules not presented to the human host, such as exclusively ookinete antigens. For several very apparent reasons a vaccine today is conceived of as subnit as opposed to show1 parasite vaccines, either in tw @]z92267631@:Ho, M. Bannister, L. H. Looareesuwan, S. Suntharasamai, P.tmCytoadherence and ultrastructure of Plasmodium falciparum-infected erythrocytes from a splenectomized patient Cell Adhesion Erythrocytes/*parasitology/ultrastructure Human Malaria, Falciparum/*blood/parasitology Microscopy, Electron Rosette Formation *Splenectomy Support, Non-U.S. Gov'teIn malarial infections of primates, the spleen has been shown to modulate parasite antigen expression on the surfaces of infected erythrocytes. The processes affected include cytoadherence, which is central to the pathophysiology of severe falciparum malaria, and the related phenomenon of rosette formation. In this study, the cytoadherence and rosette formation behaviors of Plasmodium falciparum- infected erythrocytes from a splenectomized patient were examined during the first erythrocytic cycle in vitro. Ultrastructural studies were also performed. Infected erythrocytes were found to cytoadhere to C32 melanoma cells via leukocyte differentiation antigen CD36 but not intercellular adhesion molecule 1. They also displayed on their surfaces electron-dense knobs similar in structure and density to those on infected erythrocytes from intact hosts. These findings may reflect a stable cytoadherent phenotype of the parasite isolate that is unaffected by the absence of the spleen. Alternatively, the modulating role of the spleen may have been assumed by other organs of the mononuclear phagocytic system in a previously infected individual. No rosette formation was observed, but as not all natural isolates form rosettes, this observation may or may not be related to the asplenic status of the patient. Parasite and host factors appear to be important in determining the effect of splenectomy on cytoadherence and rosette formation in human falciparum malaria.t Infect Immun 1992606 2225-887195035~Howard, R. J. Lyon, J. A. Uni, S. Saul, A. J. Aley, S. B. Klotz, F. Panton, L. J. Sherwood, J. A. Marsh, K. Aikawa, M. et al.,Transport of an Mr approximately 300,000 Plasmodium falciparum protein (Pf EMP 2) from the intraerythrocytic asexual parasite to the cytoplasmic face of the host cell membrane7`ZAnimal Antigens, Protozoan/analysis/*metabolism Aotus trivirgatus Biological Transport Cell Adhesion Cell Membrane/*metabolism Epitopes/analysis Fluorescent Antibody Technique Microscopy, Electron Molecular Weight Plasmodium falciparum/*metabolism/ultrastructure Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S.ZTThe profound changes in the morphology, antigenicity, and functional properties of the host erythrocyte membrane induced by intraerythrocytic parasites of the human malaria Plasmodium falciparum are poorly understood at the molecular level. We have used mouse mAbs to identify a very large malarial protein (Mr approximately 300,000) that is exported from the parasite and deposited on the cytoplasmic face of the erythrocyte membrane. This protein is denoted P. falciparum erythrocyte membrane protein 2 (Pf EMP 2). The mAbs did not react with the surface of intact infected erythrocytes, nor was Pf EMP 2 accessible to exogenous proteases or lactoperoxidase-catalyzed radioiodination of intact cells. The mAbs also had no effect on in vitro cytoadherence of infected cells to the C32 amelanotic melanoma cell line. These properties distinguish Pf EMP 2 from Pf EMP 1, the cell surface malarial protein of similar size that is associated with the cytoadherent property of P. falciparum-infected erythrocytes. The mAbs did not react with Pf EMP 1. In one strain of parasite there was a significant difference in relative mobility of the 125I-surface-labeled Pf EMP 1 and the biosynthetically labeled Pf EMP 2, further distinguishing these proteins. By cryo-thin-section immunoelectron microscopy we identified organelles involved in the transit of Pf EMP through the erythrocyte cytoplasm to the internal face of the erythrocyte membrane where the protein is associated with electron- dense material under knobs. These results show that the intraerythrocytic malaria parasite has evolved a novel system for transporting malarial proteins beyond its own plasma membrane, through a vacuolar membrane and the host erythrocyte cytoplasm to the erythrocyte membrane, where they become membrane bound and presumably alter the properties of this membrane to the parasite's advantage. J Cell Biol 1987 104o51269-80p>7Igarashi, I. Oo, M. M. Stanley, H. Reese, R. Aikawa, M. 19872+Knob antigen deposition in cerebral malariaAm J Trop Med Hyg37511-515 1230 Ref11\kxv~A:*$Vernot Hernandez, J.P Heidrich, H-G. 1984Time-course of synthesis, transport and incorporation of a protein identified in purified membranes of host erythrocytes infected with a knob-forming strain of Plasmodium falciparumMol Biochem Parasitol12337-350 0066 Ref11m87299482VPWickramasinghe, S. N. Phillips, R. E. Looareesuwan, S. Warrell, D. A. Hughes, M.XRThe bone marrow in human cerebral malaria: parasite sequestration within sinusoidsAdolescence Adult Aged Bone Marrow/blood supply/*pathology/parasitology Brain Diseases/*pathology/parasitology Female Human Malaria/*pathology/parasitology Male Microscopy, Electron Plasmodium falciparum/ultrastructure Support, Non-U.S. Gov'tBone marrow aspirates from patients with cerebral malaria were studied with the light and electron microscopes. Various abnormalities were found including: (1) an increase in plasma cells and macrophages, sometimes to a marked degree; (2) phagocytosis of parasitized red cells by macrophages and of merozoites by neutrophil metamyelocytes, neutrophil granulocytes and macrophages; (3) an increase in the proportion of eosinophil granulocytes and their precursors; (4) the presence of giant metamyelocytes; and (5) morphological abnormalities of erythroblasts, particularly irregularly-shaped nuclei and karyorrhexis. A high percentage of the red cells within marrow sinusoids were parasitized and the parasitized cells were attached to the endothelium. Some marrow sinusoids were packed with and completely obstructed by parasitized cells. Strands of electron-dense material were sometimes found connecting the knobs of parasitized red cells to endothelial cells or to the knobs of adjacent parasitized red cells. A striking finding was a complex interdigitation between cytoplasmic processes developed by some of the parasitized red cells and those developed by the endothelial cells to which they were attached. Occasionally, cytoplasmic processes arising from marginated parasitized red cells completely penetrated the endothelial cell and emerged extravascularly. Several parasitized red cells were also found extravascularly between haemopoietic cells. Sequestration of parasitized red cells within small blood vessels may play a part in the pathogenesis not only of the encephalopathy of cerebral malaria but also of the bone marrow dysfunction in severe malaria.  Br J Haematol 1987663295-306871755860*Winograd, E. Greenan, J. R. Sherman, I. W.Expression of senescent antigen on erythrocytes infected with a knobby variant of the human malaria parasite Plasmodium falciparumZSAnimal Antigens, Protozoan/*genetics Band 3 Protein/immunology Carrier Proteins/*genetics Erythrocyte Membrane/immunology/ultrastructure Erythrocytes/*immunology Fluorescent Antibody Technique Human IgG/genetics/isolation & purification Microscopy, Electron Plasmodium falciparum/*genetics Support, U.S. Gov't, P.H.S. *Variation (Genetics)iXRErythrocytes infected with a knobby variant of Plasmodium falciparum selectively bind IgG autoantibodies in normal human serum. Quantification of membrane-bound IgG, by use of 125I-labeled protein A, revealed that erythrocytes infected with the knobby variant bound 30 times more protein A than did noninfected erythrocytes; infection with a knobless variant resulted in less than a 2-fold difference compared with noninfected erythrocytes. IgG binding to knobby erythrocytes appeared to be related to parasite development, since binding of 125I- labeled protein A to cells bearing young trophozoites (less than 20 hr after parasite invasion) was similar to binding to uninfected erythrocytes. By immunoelectron microscopy, the membrane-bound IgG on erythrocytes infected with the knobby variant was found to be preferentially associated with the protuberances (knobs) of the plasma membrane. The removal of aged or senescent erythrocytes from the peripheral circulation is reported to involve the binding of specific antibodies to an antigen (senescent antigen) related to the major erythrocyte membrane protein band 3. Since affinity-purified autoantibodies against band 3 specifically bound to the plasma membrane of erythrocytes infected with the knobby variant of P. falciparum, it is clear that the malaria parasite induces expression of senescent antigen.Proc Natl Acad Sci U S A 1987847o 1931-589093233"Winograd, E. Sherman, I. W.Characterization of a modified red cell membrane protein expressed on erythrocytes infected with the human malaria parasite Plasmodium falciparum: possible role as a cytoadherent mediating protein Animal Antibodies, Monoclonal Band 3 Protein/*analysis/immunology/physiology *Cell Adhesion Erythrocyte Membrane/*analysis Erythrocytes/analysis/cytology/*parasitology Peptide Mapping Plasmodium falciparum/*physiology Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S./rlInfections with the human malaria Plasmodium falciparum are characterized by the retention of parasitized erythrocytes in tissue capillaries and venules. Erythrocytes containing trophozoites and schizonts attach to the endothelial cells that line these vessels by means of structurally identifiable excrescences present on the surface of the infected cell. Such excrescences, commonly called knobs, are visible by means of scanning or transmission electron microscopy. The biochemical mechanisms responsible for erythrocyte adherence to the endothelial cell are still undefined. In an attempt to identify the cytoadhesive molecule on the surface of the infected cell, we have prepared monoclonal antibodies to knob-bearing erythrocytes infected with the FCR-3 strain of P. falciparum. One of these monoclonal antibodies, designed 4A3, is an IgM that reacts (by means of immunofluorescence) with the surface of unfixed erythrocytes bearing mature parasites of the knobby line; it does not react with knobless lines or uninfected erythrocytes. By immunoelectron microscopy the monoclonal antibody 4A3 was localized to the knob region. In an in vitro cytoadherence assay, the monoclonal antibody partially blocked the binding of knob-bearing cells (FCR-3 strain) to formalin-fixed amelanotic melanoma cells. The monoclonal antibody was used to immunoprecipitate a protein from extracts of knobby erythrocytes that had been previously surface iodinated. By a two-dimensional peptide mapping technique, the antigen recognized by the monoclonal antibody was found to be structurally related to band 3 protein, the human erythrocyte anion transporter. J Cell Biol 1989 108B10 23-30  &G' Lanners, H. N. Trager, W.sComparative infectivity of knobless and knobby clones of Plasmodium falciparum in splenectomized and intact Aotus trivirgatus monkeys Z Parasitenkd 198470 739739-745 84205777 Lanners, H. N. Trager, W.piIntranuclear structures in pyrimethamine-resistant isolates of the malaria parasite Plasmodium falciparum`Animal Cell Nucleolus/ultrastructure Cell Nucleus/*ultrastructure Clone Cells Drug Resistance, Microbial Plasmodium falciparum/drug effects/*ultrastructure Pyrimethamine/*pharmacologyxqThe ultrastructure of the malaria parasite Plasmodium falciparum is well known, both from natural infections and from culture material ( Aikawa , 1977, Langreth et al., 1978). It is noteworthy that all of these studies were done with pyrimethamine-sensitive strains, e.g. FCR- 3/Gambia. Except for spindle microtubules during schizogony, no intranuclear structures have been described in any of the asexual erythrocytic stages. In the course of isolating clones from the pyrimethamine-resistant strain Honduras I/CDC (V.K. Bhasin and W. Trager , in print) and checking by electron microscopy for the presence or absence of knobs, we noticed intranuclear structures that might be correlated with pyrimethamine resistance. For comparison, we then examined the multi-drug-resistant strain Indochina 1. We present here a first report on these structures as a basis for further studies.Cell Biol Int Rep 198483 221-594344771>8Lanzer, M. Wertheimer, S. P. de Bruin, D. Ravetch, J. V.`YChromatin structure determines the sites of chromosome breakages in Plasmodium falciparum.Animal Base Sequence Cell Nucleus/metabolism Chromatin/*chemistry Chromosomes/*metabolism Deoxyribonuclease BamHI DNA, Protozoan/chemistry/metabolism *Genes, Protozoan Micrococcal Nuclease/metabolism Molecular Sequence Data Nucleosomes/metabolism Plasmodium falciparum/*genetics Polymerase Chain Reaction Repetitive Sequences, Nucleic Acid Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S.e~xSpontaneous chromosome breakages are frequently observed in the human malaria parasite Plasmodium falciparum and are responsible for the generation of novel phenotypes, which may contribute to the pathogenicity and virulence of this protozoan parasite. The identification of a hot spot of chromosome breakage within the coding region of the KAHRP gene revealed that these events do not occur randomly but follow a regular pattern with a periodicity of 155 bp. This phasing corresponds to the average repeat unit of P. falciparum nucleosomes. Furthermore, breakage events preferentially occur within the linker regions of nucleosomes, as demonstrated by mapping endonuclease hypersensitive sites of chromatin. These data suggest that, in P. falciparum, the chromatin structure is involved in the molecular process of chromosome breakage, a mechanism that may be common in other eukaryotes.Nucleic Acids Resi 199422153099-10384185810JCLeech, J. H. Barnwell, J. W. Aikawa, M. Miller, L. H. Howard, R. J.Plasmodium falciparum malaria: association of knobs on the surface of infected erythrocytes with a histidine-rich protein and the erythrocyte skeleton4-Animal *Blood Proteins Cebidae Electrophoresis, Polyacrylamide Gel Erythrocyte Membrane/*ultrastructure Glycoproteins/*blood Hemolysis Malaria/*blood Microscopy, Electron Plasmodium falciparum/*pathogenicity Proteins/isolation & purification Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S.nPlasmodium falciparum-infected erythrocytes (RBC) develop surface protrusions (knobs) which consist of electron-dense submembrane cups and the overlying RBC plasma membrane. Knobs mediate cytoadherence to endothelial cells. Falciparum variants exist that lack knobs. Using knobby (K+) and knobless (K-) variants of two strains of P. falciparum, we confirmed Kilejian's original observation that a histidine-rich protein occurred in K+ parasites but not K- variants (Kilejian, A., 1979, Proc. Natl. Acad. Sci. USA, 76:4650-4653; and Kilejian, A., 1980, J. Exp. Med., 151:1534-1538). Two additional histidine-rich proteins of lower molecular weight were synthesized by K+ and K- variants of both strains. We used differential detergent extraction and thin-section electron microscopy to investigate the subcellular location of the histidine-rich protein unique to K+ parasites. Triton X-100, Zwittergent 314, cholic acid, CHAPS, and Triton X-100/0.6 M KCl failed to extract the unique histidine-rich protein. The residues insoluble in these detergents contained the unique histidine-rich protein and electron-dense cups. The protein was extracted by 1% SDS and by 1% Triton X-100/9 M urea. The electron-dense cups were missing from the insoluble residues of these detergents. The electron-dense cups and the unique histidine-rich protein appeared to be associated with the RBC skeleton, particularly RBC protein bands 1, 2, 4.1, and 5. We propose that the unique histidine-rich protein binds to the RBC skeleton to form the electron-dense cup. The electron-dense cup produces knobs by forming focal protrusions of the RBC membrane. These protrusions are the specific points of attachment between infected RBC and endothelium.. J Cell Biol 19849841256-64 (80051095"Langreth, S. G. Reese, R. T.\UAntigenicity of the infected-erythrocyte and merozoite surfaces in Falciparum malariaRAnimal *Antigens, Surface Aotus trivirgatus/immunology Cross Reactions *Epitopes Erythrocytes/*immunology Haplorhini Human Malaria/*immunology Microscopy, Electron Molecular Conformation Plasmodium falciparum/*immunology Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S.B;The antigenicity of altered structures induced by Plasmodium falciparum in the membranes of infected Aotus monkey and human erythrocytes was examined. Antisera were obtained from monkeys made immune to malaria. Bound antibodies were shown to be localized on the knob protrusions of infected erythrocytes of both human and monkey origin and from both in vitro and in vivo infections. Therefore, P. falciparum infection has produced similar antigenic changes in the erythrocyte surfaces of both man and monkey. Uninfected erythrocytes and all knobless-infected erythrocytes bound no antibody from immune sera. Strains of P. falciparum from widely different geographic areas that were cultured in vitro in human erythrocytes induced structures (knobs) which have common antigenicity. Merozoites were agglutinated by cross-linking of their cell coats when incubated with immune sera. The binding of ferritin-labeled antibody was heavy on the coats of both homologous and heterologous strains of the parasite, indicating that the merozoite surfaces of these strains share common antigens.o J Exp Med 1979 15051241-54e85129507"Langreth, S. G. Peterson, E.xrPathogenicity, stability, and immunogenicity of a knobless clone of Plasmodium falciparum in Colombian owl monkeysAnimal Antibody Formation Aotus trivirgatus/parasitology Erythrocytes/pathology/parasitology Malaria/immunology/*parasitology Microscopy, Electron Plasmodium falciparum/immunology/*pathogenicity Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S.The pathogenicity, immunogenicity, and morphological stability of a knobless clone of strain FCR-3 of the human malaria parasite Plasmodium falciparum was investigated in Aotus monkeys. An early knob-bearing (K+), wild-type isolate of strain FCR-3 and the D3 knobless (K-) clone were adapted to Aotus monkey erythrocytes in continuous culture, establishing the parasites in Aotus cells without exposure to in vivo cellular or humoral immune responses. All monkeys, intact or splenectomized, which were infected with wild-type FCR-3 adapted to Aotus cells in vitro, developed virulent infections and had to be drug treated. The intact nonsplenectomized animals which received knobless D3 cloned parasites did not develop virulent infections even after multiple infections. The splenectomized monkeys which received the K- D3 clone had virulent infections. Late-stage wild-type K+ parasites sequestered in both intact and splenectomized monkeys, whereas late- stage D3 K- parasites did not sequester in the splenectomized animals. These results suggest that two elements affected the pathogenicity of the malaria parasites in these experiments. Knobs on K+-infected erythrocytes enabled these parasites to sequester, presumably by attachment to capillary endothelium. When present, the spleen eliminated circulating K- late-stage erythrocytes, presumably by selection on the basis of their nondeformability. Although clone D3 K- parasites are nonvirulent in intact monkeys, they induced some immunological protection against challenge with wild-type K+ parasites. The surface morphology of K--infected erythrocytes remains unaltered throughout these experiments, suggesting that loss of knobs is a stable condition.a Infect Immun 1985473 760-6ED832912980*Gruenberg, J. Allred, D. R. Sherman, I. W.Scanning electron microscope-analysis of the protrusions (knobs) present on the surface of Plasmodium falciparum-infected erythrocytesErythrocyte Membrane/*ultrastructure Erythrocytes/*parasitology/*ultrastructure Human Malaria/*blood Microscopy, Electron, Scanning Plasmodium falciparum Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S.lThe nature of the surface deformations of erythrocytes infected with the human malaria parasite Plasmodium falciparum was analyzed using scanning electron microscopy at two stages of the 48-h parasite maturation cycle. Infected cells bearing trophozoite-stage parasites (24-36 h) had small protrusions (knobs), with diameters varying from 160 to 110 nm, and a density ranging from 10 to 35 knobs X micron-2. When parasites were fully mature (schizont stage, 40-44 h), knob size decreased (100-70 nm), whereas density increased (45-70 knobs X micron- 2). Size and density of the knobs varied inversely, suggesting that knob production (a) occurred throughout intraerythrocytic parasite development from trophozoite to schizont and (b) was related to dynamic changes of the erythrocyte membrane. Variation in the distribution of the knobs over the red cell surface was observed during parasite maturation. At the early trophozoite stage of parasite development, knobs appeared to be formed in particular domains of the cell surface. As the density of knobs increased and they covered the entire cell surface, their lateral distribution was dispersive (more-than-random); this was particularly evident at the schizont stage. Regional surface patterns of knobs (rows, circles) were seen throughout parasite development. The nature of the dynamic changes that occurred at the red cell surface during knob formation, as well as the nonrandom distribution of knobs, suggested that the red cell cytoskeleton may have played a key role in knob formation and patterning. J Cell Biolp 1983973795-802 83195039"Gruenberg, J. Sherman, I. W.Isolation and characterization of the plasma membrane of human erythrocytes infected with the malarial parasite Plasmodium falciparumErythrocyte Membrane/*analysis Erythrocytes/*analysis/*parasitology Human Malaria/*blood Membrane Proteins/blood Molecular Weight Plasmodium falciparum Support, Non-U.S. Gov'tdb[Human erythrocytes infected with the malarial parasite Plasmodium falciparum were labeled metabolically with a mixture of 15 radioactive amino acids. When synchronously growing parasites were at the schizont stage of development infected cells were concentrated and purified by using a Percoll-Hypaque gradient. The plasma membrane of the infected erythrocyte, isolated by binding cells to a solid support (Affi-Gel 731, Bio-Rad), was less than 1% contaminated with parasite membranes. Erythrocyte membrane proteins were analyzed by polyacrylamide gel electrophoresis and autoradiography. Despite the high sensitivity of the procedure, there was no evidence for the insertion of parasite proteins into the infected host cell membrane. One possible exception is a Mr 230,000 parasite protein present maximally as 9,000 copies per infected erythrocyte membrane. Moreover, no differences in the membrane proteins were observed between a highly knobby clone and a knobless clone of the same strain of P. falciparum. These findings appear to rule out the presence of parasite protein(s) playing a structural role in the formation of knobs on the erythrocyte surface and question whether the antigenic determinants on the P. falciparum-infected erythrocyte are of parasite origin or whether such antigens represent newly exposed or chemically modified erythrocyte determinants.mProc Natl Acad Sci U S A 19838041087-91sb\Hadley, T. J. Leech, J. H. Green, T. J. Daniel, W. A. Wahlgren, M. Miller, L.H. Howard, R.J. 1983haA comparison of knobby (K+) and knobless (K-) parasites from two strains of Plasmodium falciparum@Mol Biochem Parasitol.9271-278g 0142 Ref1197274003*#Hirawake, H. Kita, K. Sharma, Y. D.rlVariations in the C-terminal repeats of the knob-associated histidine- rich protein of Plasmodium falciparumAmino Acid Sequence Animal Antigens, Protozoan/*chemistry Honduras Human India Malaria, Falciparum/parasitology Molecular Sequence Data Peptides/*chemistry Plasmodium falciparum/*chemistry Protozoan Proteins/*chemistry Repetitive Sequences, Nucleic Acid Sequence Alignment@:The knob-associated histidine rich protein (KAHRP) of Plasmodium falciparum plays an important role in the pathophysiology of cerebral malaria. In the present study, the immunogenic C-terminal repeat domain of the KAHRP gene was amplified, cloned and sequenced from the Indian (RJ181) and Honduran (HB3) isolates of P. falciparum. Based on the number and types of repeats in the domain, we report here the presence of three unique variant forms of KAHRP among these isolates. The Indian isolate (RJ181) contained four units of the decapeptide repeats whereas the Honduran isolate (HB3) contained two forms i.e. one form containing four decapeptide repeats plus a tetrapeptide subunit and the other form containing three decapeptide repeats plus a tetrapeptide subunit. Thus, all together, the number of KAHRP variants is increased to five which includes previously described two variants, each containing either 3 or 5 decapeptide repeats. This high rate of variability in the antigenic domain of the KAHRP gene via deletion or addition of whole or part of the decapeptide units could be involved in the evasion of host immune system possibly by providing the speculative complementarity to the vargene product. The results of the present study will be useful in designing the suitable molecular therapeutic reagents for cerebral malaria.Biochim Biophys Acta 1997 13602 105-8<t:v94`F94142586:3Smith, H. Crandall, I. Prudhomme, J. Sherman, I. W.hbOptimization and inhibition of the adherent ability of Plasmodium falciparum-infected erythrocytesAnimal Antibodies, Monoclonal/immunology Antibodies, Protozoan/immunology Antimalarials/pharmacology Buffers Calcium/pharmacology Cell Adhesion/drug effects Culture Media/pharmacology Erythrocytes/*parasitology Human Hydrogen-Ion Concentration Malaria, Falciparum/blood/*parasitology Melanoma/pathology Mice Plasmodium falciparum/drug effects/*physiology Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S. Tumor Cells, CulturedThe vast majority of the 1-2 million malaria associated deaths that occur each year are due to anemia and cerebral malaria (the attachment of erythrocytes containing mature forms of Plasmodium falciparum to the endothelial cells that line the vascular beds of the brain). A "model system" for the study of cerebral malaria employs amelanotic melanoma cells as the "target" cells in an in vitro cytoadherence assay. Using this model system we determined that the optimum pH for adherence is 6.6 to 6.8, that high concentrations of Ca2+ (50mM) result in increased levels of binding, and that the type of buffer used influences adherence (Bis Tris > MOPS > HEPES > PIPES). We also observed that the ability of infected erythrocytes to cytoadhere varied from (erythrocyte) donor to donor. We have produced murine monoclonal antibodies against P. falciparum-infected red cells which recognize modified forms of human band 3; these inhibit the adherence of infected erythrocytes to melanoma cells in a dose-responsive fashion. Antimalarials (chloroquine, quinacrine, mefloquine, artemisinin), on the other hand, affected adherence in an indirect fashion i.e. since cytoadherence is due, in part, to the presence of knobs on the surface of the infected erythrocyte, and knob formation is dependent on intracellular parasite growth, when plasmodial development is inhibited so is knob production, and consequently adherence is ablated. Mem Inst Oswaldo CruzO 199287Suppl 3  303-1284125828"Stanley, H. A. Reese, R. T.ZSIn vitro inhibition of intracellular growth of Plasmodium falciparum by immune sera  Animal Aotus trivirgatus Chloroquine/pharmacology Erythrocytes/parasitology Human Immune Sera/*pharmacology Malaria/immunology Methionine/metabolism Plasmodium falciparum/drug effects/*growth & development Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S.mBeginning at the ring stage, synchronized cultures of Plasmodium falciparum were grown in suspension for 22-32 hours. Intracellular growth was assayed by measuring cellular uptake and incorporation into protein of 35S-methionine. Low concentrations (2%) of serum from immune humans and Aotus monkeys were found to inhibit the uptake of the 35S- methionine. The amount of inhibition for a given serum was often inversely related to its indirect fluorescent antibody test titer. Inhibition occurred during the trophozoite stage and was not obtained with a clone lacking the erythrocyte modifications referred to as knobs. Thus, a sensitive new assay is described which allows detection of factors in immune primate sera which can affect maturation of P. falciparum within the erythrocyte. These serum factors are likely to be antibodies which react with antigens expressed at the trophozoite stage on the surface of K+-infected erythrocytes.oAm J Trop Med HygT 1984331p 12-6,&Tan Ariya, P. Yang, Y. F. Kilejian, A.|vPlasmodium falciparum: comparison of the genomic organization of the knob protein gene in knobby and knobless variants Exp Parasitoln 198867129-136 Ref11~wTaylor, D. W. Parra, M. Chapman, G. B. Stearns, M. E. Rener, J. Aikawa, M. Uni, S. Aley, S.B. Panton, L.J. Howard, R.J./lfLocalization of Plasmodium falciparum histidine-rich protein 1 in the erythrocyte skeleton under knobsMol Biochem Parasitol. 198725165-174^ Ref1184275495\UThaithong, S. Beale, G. H. Fenton, B. McBride, J. Rosario, V. Walker, A. Walliker, D. XRClonal diversity in a single isolate of the malaria parasite Plasmodium falciparumAnimal Clone Cells/classification Drug Resistance, Microbial Human Plasmodium falciparum/classification/enzymology/*genetics Support, Non-U.S. Gov't *Variation (Genetics)Clones of an isolate of Plasmodium falciparum from Mae Sod (Thailand) were prepared by a dilution procedure. Some of the parasite cultures thus obtained have been typed for the following characters: (i) electrophoretic variants of three enzymes; (ii) susceptibility to chloroquine and pyrimethamine; (iii) antigen diversities recognized by ten strain-specific monoclonal antibodies; (iv) presence or absence of knobs on infected erythrocytes and (v) two-dimensional PAGE variants of seven proteins. Amongst the clones there was variation involving each of these five characters. At least seven different types of clones were found in ten cultures produced by dilution. The amount of phenotypic variation within a single isolate has thus been shown to be surprisingly great. Variations in drug susceptibility and antigens are considered to be particularly important in view of their relevance to anti-malarial treatments. 1984Trans R Soc Trop Med Hyg782 242-5 Using Smart Source ParsingB