[Suppressor mechanism in tumor immunology: characteristics of suppressor T-cells in glioma-bearing mice].

Suppressor T cells in syngeneic tumor-bearing mice that inhibited in vitro generation of tumor antigen-specific cytotoxic T lymphocytes were characterized with respect to the kinetics, the nature and the target specificity, using murine malignant glioma (a methylcholanthrene-induced malignant ependymoblastoma, 203-glioma). Suppressor cell activity was assessed by the inhibition of tumor cell killing activity of cytotoxic T lymphocytes, which were prepared from splenic T enriched lymphocytes of mice immunized with 1 X 10(6) mitomycin C (50 micrograms/ml, 45 minutes)-treated 203-glioma cells twice at an interval of 7 days. It was confirmed that suppressor T cells were generated in 203-glioma-bearing mice, and they were tumor antigen-specific as evidenced by the fact that sensitized splenic T lymphocytes from mice bearing other syngeneic EL4 thymoma or allogeneic P 815 mastocytoma or YAC-1 T cell lymphoma did not exhibit the inhibition of the cytotoxic T lymphocyte activity against 203-glioma cells. Significant suppressor cell activity was detected in spleen cells 1 to 5 days after the subcutaneous inoculation of 203-glioma cells with the peak activity on day 3 and it disappeared as early as on day 7, suggesting strongly that the turn-over of suppressor T cells is very quick. Surface markers of suppressor T cells in 203-glioma-bearing mice were checked on day 3 with the results that the suppressor cell activity was eliminated by the treatment with anti-Lyt-2 monoclonal antibody and complement, indicating that the phenotype of suppressor T cells is Lyt-1-.2.3+.(ABSTRACT TRUNCATED AT 250 WORDS)