Production of tumor-specific suppressor T cell hybridomas.

Spleen cells from late tumor-bearing host mice (TBH) with progressive P815 tumors have been shown to suppress the generation of cytotoxic T lymphocytes (CTL) from spleens of syngeneic immune or early TBH mice in vitro. This suppression is antigen-specific and is mediated by T lymphocytes. By positive selection, a highly enriched population of T cells was obtained from late TBH spleens and fused with the BW5147 HAT-sensitive thymoma. Cloned hybrid cell lines were obtained which released soluble antigen-specific factors capable of suppressing anti-P815 CTL generation. Similar T cell hybrids with suppressive activity were also derived from the fusion of spleen cells of TBHs bearing a HAT-sensitive subline of the P815 tumor.