ESTABLISHMENT OF A NATURAL SUPPRESSOR-CELL LINE PRODUCING SOLUBLE SUPPRESSOR FACTOR OTHER THAN TRANSFORMING GROWTH-FACTOR-BETA

Natural suppressor (NS) cell line (Clone 59) was established from the bone marrow of adult C3H/Hej mice in the presence of WEHI-3 conditione d media. Clone 59 cells suppressed the generation of cytotoxic T lymph ocytes from normal mouse spleen. This suppression was seen at a respon der-to-suppressor cell ratio of 1000:1 and lacked antigen specificity or MHC restriction. Clone 59 cells expressed the 'null' surface phenot ype (Thy1.2(-), CD3(-), Lyt-2(-), L3T4(-), surface Ig(-), MAC-1(-)) by immunofluorescent staining. Clone 59 cells exhibited no cytolytic act ivity against NK cell-sensitive YAC-I and natural cytotoxic L929 targe t cell lines. Non-specific suppression, with a cell-free supernatant f rom the Clone 59-NS cells, also was observed. The supernatant did not inhibit [H-3]-thymidine uptake by CTLL-2 cells which were proliferatin g in response to IL-2. Anti-transforming growth factor-P (TGF-beta) mo noclonal antibody had no effect on suppression, suggesting that the no n-specific suppression is mediated by some soluble factors other than TGF-P. Clone 59 cells may be useful in identifying non-specific suppre ssor cells in adult bone marrow and studying their functional role in the regulation of tolerance and self-reactivity,