Protective antigen in the membranes of mouse erythrocytes infected with Plasmodium chabaudi.

A malarial antigen, Pc96, in the plasma membrane of erythrocytes infected with Plasmodium chabaudi has been identified. It is synthesized by the parasite and present during most of the growth stages of the intra-erythrocytic cycle as demonstrated by immunofluorescence. The antigen has a molecular weight of approximately 96,000. Monoclonal antibodies raised against this antigen were used to isolate the protein by affinity chromatography. Mice immunized with affinity-purified Pc96 were partially protected against blood induced-P. chabaudi infection. This result indicates the existence of a protective antigen in the membranes of erythrocytes parasitized by a rodent malaria and encourages the search for analogous antigens in human malaria parasites as possible candidate molecules for malaria vaccination.