Depletion of CD8+ T cells suppresses growth of Trypanosoma brucei brucei and interferon-gamma production in infected rats

Abstract

Sprague-Dawley rats infected with Trypanosoma brucei brucei showed a strong and rapid induction of splenocyte IFN-γ (within 12 h post-infection) as measured by a single cell assay for IFN-γ secretion. Depletion of CD8+ cells in infected rats abrogated the IFN-γ production, suppressed parasite growth and increased survival of the animals. Induction of MHC class I antigens in the paraventricular and supra-optic hypothalamic nuclei caused by the trypanosome infection was also inhibited by the CD8+ cell depletion. It is suggested that the CD8+ cells are involved directly or indirectly in growth regulation of the parasite and that IFN-γ induced by the parasite may be one of the factors that trigger MHC expression and immunosuppression.