Antibodies from immune African donors with a protective effect in Plasmodium falciparum human infection are also able to control asexual blood forms of the parasite in Saimiri monkeys.

We have recently shown that an IgG preparation obtained from immune African donors was able to control Plasmodium falciparum multiplication in the blood of Thai patients, but had no inhibitory activity against the parasite in vitro. The same IgG preparation was passively transferred to Saimiri monkeys acutely infected with two different strains of P. falciparum, one of African origin and the other from French Guyana. A dose-dependent in vivo inhibition of parasite development was observed with both strains. The results justify the use of Saimiri monkeys for malaria vaccine trials and permit the introduction of new techniques for screening of candidate antigens for vaccines.