Expression of a 16,000 molecular weight antigen on human suppressor T lymphocytes

When SJL mice are irradiated and reconstituted with syngeneic bone marrow (XBM) they support growth of transplantable reticulum cell sarcoma to approximately 60% of that in normal mice. The ability to support RCS growth gradually improves with time after irradiation and reaches 90% of normal by 8–12 weeks. However, if the mice are thymectomized 4 weeks prior to treatment (Tx-XBM) they initially show 50% which increases to only 65% of growth in normal mice after 12 weeks. The ability of lymphoid cells from these mice to proliferate in vitro in response to irradiated RCS cells is normal 4 weeks after treatment in XBM, but remains <10% of normal in Tx-XBM mice. Nude mice of SJL background also show greatly diminished RCS growth. It is concluded that T cells promote RCS growth in vivo possibly via their tendency to proliferate upon exposure to RCS.