Antibodies that inhibit malaria replication in the bloodstream
Schematic picture of a merozoite
A particular focus of our research is the identification of antibodies that inhibit the replication and growth of P. falciparum in the bloodstream. This type of antibody is thought to be important both in acquired immunity and as mediators of immunity generated by vaccination. However, the role of these antibodies in protection from clinical disease has not been established and the primary targets of inhibitory antibodies remain unclear.
We are examining the acquisition and targets of antibodies that inhibit P. falciparum invasion of red blood cells and the potential role of invasion-inhibitory antibodies in protective immunity. To achieve these goals, we are combining novel approaches using transgenic parasite lines in functional assays with unique samples from well defined clinical cohort studies in Kenya and Papua New Guinea. In recent studies (Persson et al 2008), we have identified two erythrocyte invasion ligand families, known as the EBA and PfRH proteins, as important targets of inhibitory antibodies. P. falciparum can switch between the use of different members of the EBA and PfRH invasion ligands, which facilitates evasion of immune responses. A malaria vaccine may need to target multiple ligands in order to generate an immune response that counters malaria's immune evasion strategy.