MALARIA IMMUNITY AND VACCINATION (MICHIGAN)

falciparum". Soluble antigens obtained as exoantigens from the exhausted culture medium or from extracts of specific parasite stages will be used to immunize coccidia-free rabbits, guinea pigs, or Saimiri monkeys. Antiparasite sera from these immunized animals will be used to identify parasite antigens. These soluble antigens will be isolated and purified using column chromatography, ion-exchange chromatography, disc-gel electrophoresis, isoelectro-focusing, dissection of specific antigen-antibody bands from crossed-electrophoresis gels, and other physio-chemical, preparative electrophoretic, and immunoelectrophoretic methods. If applicable, comparisons will be made between soluble antigens obtained from strains of "P. falciparum" from different geographical regions. In the second year, partially characterized soluble parasite antigens will be tested as possible vaccines. Rabbit, guinea pig, and Saimiri monkey sera obtained from animals immunized with soluble parasite antigens will be tested for inhibitory antibodies in "P. falciparum" cultures. To determine which antigens may neutralize the inhibitory activity of the serum, soluble parasite antigens will be reacted with serum obtained in Sudan from individuals functionally immune to malaria. Those antigens which react with human antimalarial sera will be further characterized by testing for cross-strain protection, comparative immunoelectrophoresis, and polyacrylamide gel electrophoresis of radiolabeled parasite antigens precipitated by using immune sera. In the third year, those soluble parasite antigens which have been isolated and partially purified will have their subcellular positions determined using electron microscopic immunolabeling techniques. The project will finance the salaries of one part-time and two full-time research scientists and some equipment and supplies. Project activities will take place at MSU and at Ministry of Health facilities in Khartoum, Sudan.