Role of T suppressor cells in the cycling of the immune response against a murine fibrosarcoma.
Antitumor immunity against a fibrosarcoma in C57BL/6 mice was obtained by means of a semi-allogenic somatic hybrid cell derived from the fusion of this C57BL/6 fibrosarcoma (MCB6-1) and A9 cells of C3H origin. In a Winn assay, this immunity could be transferred by T lymphocytes to normal C57BL/6 recipient mice during an early and a late phase after immunization. There appeared to be a transient non-responsive period during which no immunity could be transferred. Injection of cyclophosphamide (CY) into mice before immunization increased the level of immunity during this period, and reconstitution of animals with normal spleen cells abolished the effect of CY. During the non-responsive period, suppressor cells were demonstrated in the spleen: the i.v. transfer of these suppressor cells to normal mice significantly inhibited the induction of antitumor immunity; the suppressive effect was transferred by T lymphocytes of the Lyt-2+ phenotype. No suppressive effect on antitumor protection was observed when suppressor cells were transferred simultaneously with immune T lymphocytes in the Winn assay. From these findings, it appears that T-suppressor cells regulate the antitumor response, interfering with the afferent (induction) arm of the immune response.
D000818:Animals; D003520:Cyclophosphamide / Q000494:pharmacology; D005260:Female; D005354:Fibrosarcoma / Q000276:immunology*; D007108:Immune Tolerance; D007116:Immunization, Passive; D051379:Mice; D008810:Mice, Inbred C57BL; D013601:T-Lymphocytes / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
D003520:Cyclophosphamide