| Abstract: | When spleen cells primed in vivo against allogeneic lymphoid cells were used as responder cells in secondary mixed lymphocyte cultures, a high degree of cytotoxicity was generated even in the absence of splenic adherent cells. However, removal of adherent cells from such primed responder spleen cells reduced the cytotoxicity to some extent. On the other hand, when these responder cells were transferred into the peritoneal cavity of irradiated syngeneic mice together with antigenic cells, unseparated responder cells generated a lower degree of cytotoxicity than did adherent cell-depleted responder cells. In an in vitro system, peritoneal adherent cells also suppressed the generation of cytotoxic T lymphocytes by unseparated responders; however they augmented the cytotoxic T lymphocyte generation by adherent cell-depleted responders. These adherent cell populations with augmenting activity became inhibitory when they coexisted. The mechanism of this inhibitory action remains unclear. |
