Merozoite vaccination of douroucouli monkeys against falciparum malaria.

Erythrocytic merozoites of Plasmodium falciparum (Gambia) were isolated from cultures of schizont-infected human red cells on CF 11 cellulose columns. Douroucouli monkeys vaccinated with such preparations stored in liquid nitrogen and then emulsified in Freund's complete adjuvant (F.C.A.), were resistant to successive challenges with West African (Lagos) and East African (Uganda Palto-Alto) strains of P. falciparum. The induced immunity is specific since vaccination with P. knowlesi merozoites in F.C.A. does not modify the course of P. falciparum infections in douroucouli monkeys.