Effector functions of CD8-positive guinea pig T lymphocytes

The response of guinea pig T lymphocytes to different stimuli was analysed with focus on the functions of CD8-positive T cells, which so far had been poorly defined in this animal model. For identification and purification of guinea pig cytotoxic T lymphocytes, three monoclonal antibodies, directed against the CD8 differentiation antigen were characterized and compared with respect to expression pattern and biochemical characteristics of the corresponding cell surface antigen. The antibodies were used for the identification of the cytotoxic T lymphocyte subpopulation within alloreactive T cell lines, and for the depletion of CD8-positive cells in in vitro assays. Purified CD4- and CD8-positive cells were tested for their ability to proliferate in response to antigen, mitogen or anti-guinea pig Thy-1 monoclonal antibodies. Both, CD4- and CD8-positive cells showed IL-2 release and subsequent proliferation after polyclonal stimulation. Cytotoxic activity in CD8-positive alloreactive T cells was expressed in vitro only after repeated stimulation.