Polymorphism of a 35–48 kDa Plasmodium falciparum merozoite surface antigen

Glycoproteins of the asexual blood stages of Plasmodium falciparum were labelled with radioactive glucosamine and analysed by two-dimensional electrophoresis. Four major glycoproteins were detected in all eight parasite isolates studied. Two of the glycoproteins, designated GP2 and GP4, were invariant among the isolates, while the other two GP1 and GP3 were found to be polymorphic in both their biochemical and antigenic properties. By immunoblotting and immunoprecipitation with specific monoclonal antibodies, the two polymorphic glycoproteins were identified as surface antigens of merozoites.