Protection of Aotus monkeys from malaria infection by immunization with recombinant hybrid proteins. Infect. Immun

On the basis of investigations of the malarial blood-stage antigens SERP, HRPII, and MSAI from Plasmodium fakciparum, we chose two Escherichia coli-expressed hybrid proteins containing selected partial sequences of these antigens. Antibodies raised against both hybrid proteins in rabbits and Aotus monkeys recognize the corresponding P. fakciparum polypeptides. In two independent trials with 13 animals, immuni-zation of Aotus monkeys with either of the two hybrid proteins administered in a well-tolerated oil-based formulation protected the animals from an experimental P. falciparum infection. Malaria tropica, the most widespread and dangerous trop-ical parasitic disease, is caused by the protozoan Plasmo-diumfalciparum. Resistance of the parasites to a wide range of drugs has rapidly increased in recent years and keeps spreading. To protect the health of those at risk, vaccines are urgently needed for malarial control. A number of antigens from the asexual blood stages of the malarial parasite are being considered as candidates for the development of a vaccine