Induction of gamma delta T cells during acute murine infection with Toxoplasma gondii

The importance of the host y delta T cell response to microbial pathogens is not yet fully understood, We report that inbred mice infected with T. gondii developed a gamma delta T cell proliferative response to parasite Ag, Mice depleted of either the cup or gamma delta TCR were found to be significantly more susceptible to infection than the parent mouse strain. Proliferation of gamma delta T cells was observed in mice deficient in the TCR-alpha beta in response to UV-irradiated parasites. These T cells lyse parasite-infected syngenic macrophages. Adoptive transfer of these gamma delta T cells into beta 2 microglobulin-deficient mice that have been depleted of both CD4(+) and NK cells prolongs survival against acute parasite challenge when compared with nontransferred controls, The gamma gamma T cells isolated from infected alpha -/- mice express a 10-fold increase in mRNA and produce high titers of IFN-gamma. These data suggest that gamma delta T cells may play an important role in the early host response to infection with T. gondii.