Immunological cross-reactivity of the histidine-rich protein of Plasmodium lophurae and the knob protein of Plasmodium falciparum.

Rabbits were immunized with the histidine-rich protein (HRP) of the avian malaria parasite, Plasmodium lophurae. The anti-HRP immunoprecipitated the knob protein (KP) from extracts of the human parasite, Plasmodium falciparum. The anti-HRP did not react with any antigens of a laboratory-derived strain of P. falciparum (K-) that does not form knobs. Antisera raised against a membrane-enriched fraction of P. falciparum-infected erythrocytes as well as sera from humans exposed to P. falciparum infections immunoprecipitated HRP from P. lophurae extracts.