Animals have been successflly vaccinated against sexual and asexual malaria parasites. In addition, Plasmodium falciparium, the major malaria of man, has been grown in culture for the production of asexual stages and gametocytes. The present study will: 1) Improve culture conditions for the production of large numbers of gametocytes, gametes and merozoites of P. falciparium; 2) Study of the physiology of exflagellation, fertilization and invasion of red cells by malaria merozoites; 3) Characterize structure, function and immunogenicity of surface determinants on gametes and merozoites; 4) Evaluate gamete vaccines in model systems for identification of the best antigens and adjuvants.