Immunity to malaria
Children in Papua New Guinea
In malaria-endemic areas effective immunity against malaria develops after repeated exposure that limits blood-stage parasitemia and prevents severe disease and complications, but does not fully prevent infection. Acquired immunity acts predominantly against the blood stages of parasites and antibodies are believed to be an important component of protective immunity. Antibodies target antigens of merozoites and parasitized red blood cells. Recent studies, aided by completion of the P. falciparum genome sequence, have expanded our knowledge of important merozoite antigens and their role in invasion of red blood cells by merozoites. Parasite invasion ligands are thought to be important targets of antibodies that inhibit parasite replication and prevent disease, and several are vaccine candidates. The major antigen on the surface of parasitized red blood cells is a highly polymorphic protein known as PfEMP1.
Our studies aim to establish a detailed understanding of the acquisition, decay, and maintenance of humoral immunity and the role of specific antibodies in immunity, with a particular emphasis on current vaccine candidates. We are examining antibody responses in detailed longitudinal cohort studies of children resident in malaria-endemic areas of Kenya and Papua New Guinea, in collaboration with colleagues at the Kenya Medical Research Institute, and the PNG Institute of Medical Research.