Proliferative response of T lymphocytes to allogeneic tumor without generation of killer T lymphocytes in the presence of Ehrlich ascites tumor fluid.

The presence of cell-free Ehrlich ascites tumor fluid in an appropriate concentration was shown to permit a proliferative response, strictly dependent on the presence of Thy-1-positive lymphocytes, to proceed when introduced on the initiation of mixed lymphocyte-tumor reaction of C57BL/6 lymphocytes and Mitomycin-C-treated C3H/He myeloma cells, while it clearly inhibited the development of cytotoxic killer T lymphocytes toward the priming allogeic tumor cells. The fluid had no effect, however, when added to normally primed spleen cells at the onset of cytotoxicity test. Further investigation of the mechanism in vitro by ascitic tumor fluid selectively suppresses the generation of killer T lymphocyte activity to allogeneic target cells may lead to a better understanding of the suppressed T-cell responses observed in Ehrlich tumor-bearing animals, and additionally, may provide an intriguing information about the interactions between the distinct T-cell subsets responsible for proliferative response and generation of killer T lymphocytes.