ALPHA-BETA AND GAMMA-DELTA T-CELLS IN THE IMMUNE-RESPONSE TO THE ERYTHROCYTIC STAGES OF MALARIA IN MICE

Mice lacking T cells with alpha beta TCR (TCR beta-/-) or gamma delta TCR (TCR delta-/-) were infected with the erythrocytic stages of the malaria parasite, Plasmodium chabaudi chabaudi (AS). Mice without gamma delta T cells could control and reduce a primary infection of P. chabaudi with a slight delay in the time of clearance of the acute phase of infection and significantly higher recrudescent parasitaemias compared with control intact mice. TCR delta-/- mice had higher levels of both serum Ig and malaria-specific antibodies of the isotypes IgG3 and IgG1 compared with control mice. TCR beta-/- mice, despite a striking increase in NK1.1(+) cells and the presence of gamma delta T cells, were unable to clear their infection. Although the plasma of TCR beta-/- mice contained ail Ig isotypes before and during a primary infection, they were unable to produce significant levels of malaria-specific IgG antibodies, suggesting that in the absence of alpha beta T cells gamma delta T cells are not able to provide efficient help for antibody production.