Blocking by cyclosporine of antigen–induced maturation and lymphokine secretion by cytotoxic T lymphocyte hybridomas

We have investigated the effect of cyclosporine (Cys) on the maturation of cytotoxic T lymphocytes (CTL), and on the induction of interleukin-2 (IL-2) secretion using two bifunctional CTL hybridomas. Both hybridomas can be stimulated with allogeneic cells to secrete IL-2 and to specifically kill target cells. Cys, at 10 –50 ng/ml, eliminates the induction of both functions (secretion and lysis). Although maturation of both specific and lectin-mediated killing by the hybrid cells exhibits high sensitivity to Cys, the actual killing of target cells by previously activated cells is less affected. Our results suggest that pharmacological levels of Cys directly interfere with the antigen-responsiveness of helper-independent cytotoxic T cells, as represented by these hybridomas, and prevent their maturation.