ALTERED EFFECTOR RESPONSES OF H-Y TRANSGENIC CD8(+) CELLS

The primary role of CD8(+) T cells is to destroy virus-infected or tum or cells expressing cognate antigens in the form of peptide-MHC class I complexes. This destruction is primarily achieved by the actions of lytic mediators and/or lymphokines. In this report, we show that matur e, H-Y/D-b-specific CD8(+) T cells from H-Y TCR transgenic mice were u nable to efficiently release lytic mediators after antigenic stimulati on, However, anti-TCR antibody induced granule exocytosis and target c ell lysis, arguing against signaling and/or cytolytic machinery defect s in CD8(+) cells, and demonstrating that male antigen induced differe ntiation of 'naive' into effector CD8(+) cells, Stimulation of H-Y-spe cific effector CD8(+) T cells with male stimulators, although insuffic ient to induce lytic granule release, was sufficient for H-Y-specific IFN-gamma production, Unexpectedly, this effector-phase IFN-gamma prod uction was dependent on B7-2 engagement, We hypothesize that altered e ffector functions in H-Y-specific CD8(+) cells are due to the low affi nity of TCR-antigen-MHC interaction and/or the elevated threshold of C D8(+) T cell activation.