Howard R. Higley

In Vivo Effects of TGFβ on the Cellular and Humoral Response to an Allogeneic Tumor in Mice

Transforming growth factor-@ (TGFP1) has been shown to inhibit a number of mature immune cell functions in vitro. These include T and B cell proliferation, B cell immunoglobulin secretion, T cell IL-2 production and IL-2 receptor expression, and NK and T cell cytolytic Macrophage function has been shown to be both increased and decreased in different in vitro m0delsP3~ These in vitro studies, while useful in dissecting distinct activities of TGFD, may not take into account many of the cellular interactions that occur in vivo during an immune response. The present study makes use of the immune response to an intraperitoneal (i.p.) allogeneic tumor challenge in mice to test the in vivo immunosuppressive effects of TGFP1. The data indicate that daily, subcutaneous treatments with 5 pg or more of TGFPl inhibit the splenic cytolytic T lymphocyte (CTL) response, but not the serum antibody (Ab) response seen 11 days after immunization. The results suggest that under these conditions subcutaneous TGFPl treatments result in systemic suppression of distinct arms of the immune response.