Role of T cells in preventing transmission of rodent malaria.

Transmission blocking immunity induced by microgamete vaccination is fully effective for at least 12 months. Passive transfer of immune T cells reduced transmission of a subsequent infection by 95%, the effect being partly due to a significant reduction in numbers of circulating gametocytes during the infection. This immunity was apparently independent of specific antibody, though these were produced within a few days after challenge infection and was mediated by a T cell of the GK1.5+, Ly 2.2 phenotype. Immune serum and immune T cells, administered together, showed a strong additive effect and blocked transmission completely.