Monoclonal anti-gamete antibodies prevent transmission of murine malaria.

Three monoclonal antibodies prepared using spleen cells from mice immunized with microgametes of Plasmodium yoelii nigeriensis were tested for their ability to block transmission of the infection. Two of them agglutinated microgametes and blocked transmission, this effect being antibody-dose dependent. The third monoclonal used alone was ineffective in both these assays although it stained gametocytes and microgametes by immunofluorescence in the same way as the protective monoclonals. However, when it was administered in combination with one of the protective monoclonals the transmission blocking immunity was enhanced significantly, indicating a synergistic effect of the two antibodies.