Antigenicity of the infected-erythrocyte and merozoite surfaces in Falciparum malaria.

Abstract

The antigenicity of altered structures induced by P. falciparum in the membranes of infected Aotus monkey and human erythrocytes was examined. Antisera were obtained from monkeys made immune to malaria. Bound antibodies were localized on the knob protrusions of infected erythrocytes of human and monkey origin and from in vitro and in vivo infections. P. falciparum infection produced similar antigenic changes in the erythrocyte surfaces of man and monkey. Uninfected erythrocytes and all knobless-infected erythrocytes bound no antibody from immune sera. Strains of P. falciparum from widely different geographic areas that were cultured in vitro in human erythrocytes induced structures (knobs) which had common antigenicity. Merozoites were agglutinated by cross-linking of their cell coats when incubated with immune sera. The binding of ferritin-labeled antibody was heavy on the coats of homologous and heterologous strains of the parasite, indicating that the merozoite surfaces of these strains share common antigens.