T cell subsets involved in the rejection of metastases arising from intraocular melanomas in mice.

The role of cell-mediated immunity in the resistance to spontaneous metastasis of intraocular melanoma was studied in C57BL/6 mice harboring syngeneic B16F10 melanomas. Mice were rendered T cell-deficient by thymectomy and lethal whole-body X-irradiation. Adult thymectomized and bone marrow-restored (ATXBM) mice were selectively reconstituted with immune lymph node cell suspensions that were depleted of specific T cell subsets. The selectively reconstituted hosts were used to evaluate the role of specific T cell subsets in controlling the metastatic spread of intraocular melanomas. The results revealed that T cell-deficient ATXBM mice were highly vulnerable to the metastatic spread of intraocular melanomas. However, this susceptibility could be virtually eliminated by the infusion of either normal or specifically sensitized lymphoid cells. Negative selection experiments demonstrated that the effector cells responsible for protection against metastases resided in a population with the surface phenotype characteristic of cytotoxic T lymphocytes: Thy 1+, Lyt 1+ and Lyt 2+.