| Abstract: | This report describes the induction, phenotypic characteristics, and functional properties of a continuous suppressor T cell line. This cell line, UV1, is capable of suppressing anti-tumor immune responses both in vivo and in vitro. The UV1 cell line was derived from a T cell-enriched (nylon wool nonadherent, Ia-negative panned fraction) spleen cell population from a ultraviolet radiation-(UV) exposed BALB/c Wehi mouse. By using an in vivo functional assay designed to demonstrate tumor-specific UV-induced suppressor T lymphocyte (Ts cell) activity, it was found that UV1 cells were capable of rendering normal syngeneic mice susceptible to the growth of UV-induced regressor tumors. In addition to their suppressive activity in vivo, UV1 cells displayed in vitro suppressive activity by blocking the differentiation of cytotoxic T cells from the draining lymph nodes of UV-tumor immunized animals. By flow cytometric analysis it was determined that UV1 cells expressed a number of T lymphocyte differentiation antigens and did not express any detectable amounts of surface immunoglobulin, I-A or E/C antigens, Fc receptors, or macrophage antigens. These data suggest that the UV1 cell line may be representative of the UV-induced Ts cell population and provide a potential means for studying UV-induced immunoregulatory mechanisms in greater detail. |
