Analysis of the mechanism of allograft rejection and cell-mediated immunity. II. Divergent effect of CY pretreatment on the generation of cytotoxic activity in the draining lymph nodes and spleen

CY pretreatment augmented the generation of cytotoxicity in the draining lymph node cells in mice after subcutaneous immunization with allogeneic spleen cells, or in the non-adherent peritoneal exudate cells after intraperitoneal immunization with these cells. Marginal cytotoxicity in the spleen cells after this immunization was suppressed by CY pretreatment. Similar divergent effect of CY pretreatment on the generation of cytotoxic activity in the draining lymph nodes and the spleen was also observed after immunization with allogeneic tumour cells which can induce high degrees of cytotoxicity without CY pretreatment. These results indicate that cytotoxic T lymphocyte (CTL) generation at the site of direct graft rejection appear to have a nature different from that related to CTL generation in the spleen. A discussion is made as to the role of CTL in the peripheral site and the spleen in cases of in vivo allograft rejection.