Immunization against Plasmodium falciparum asexual blood stages using soluble antigens

Saimiri sciureus monkeys have been successfully immunized against a human malaria parasite, Plasmodium falciparum, using soluble antigens purified from schizont and merozoite extracts. High levels of antibodies reacting with schizont and merozoite specific polypeptides of 140 and 200 kdaltons were detected in the sera of protected monkeys. The five immunized monkeys survived a challenge infection with 5 X 10(7) parasites inducing a fulminant disease in control monkeys.