“…To determine whether TGF-,B secreted in the latent form can be immunoregulatory, a TGF-,81 cDNA driven by the simian virus 40 early promoter was transfected into a highly immunogenic, C3H-derived, UV-induced fibrosarcoma, designated 1591. The 1591 tumor is highly immunogenic and expresses three major histocompatibility complex class I antigens not found in the genome of the k haplotype (6)(7)(8). The tumors elicit a primary cytolytic T-lymphocyte (CTL) response in vitro, and tumor rejection requires CD8+ T cells, which recognize the K216 gene product (9).…”