Immunoprecipitation of biosynthetically-labelled proteins from different Papua New Guinea Plasmodium falciparum isolates by sera from individuals in the endemic area.

The human serum antibody response to Plasmodium falciparum infection in Papua New Guinea has been studied by electrophoretic analysis of immunoprecipitated biosynthetically-labelled malaria proteins from three different isolates maintained in long-term in vitro culture. Differences in protein antigenic composition in different lines have been described and simplified by examination of antigens recognized only by hyperimmune serum. An in vitro assay has been used to screen various human sera containing antimalarial antibody for their ability to inhibit parasite growth and the immunoprecipitation profiles of non-inhibitory sera have been compared with those of a hyperimmune serum pool. In the discussion, emphasis is placed on the value of immunoprecipitation analyses using clinically-defined sera with known in vitro function in the identification of antigens which may be responsible for the induction of host-protective immunity.