Abstract
The role of macrophages and of macrophage-lymphocyte co-operation in the induction of T-suppressor cell activity in rats with adjuvant arthritis was investigated. Macrophages from arthritic rats had no direct effect on the induction of T-suppressor cells, but, in the presence of arthritic rats' lymphocytes or supernatants from such lymphocytes, macrophages inhibited the induction of T-suppressor cell activity. Addition of indomethacin during the induction of T-suppressor cells reduced the inhibitory effects, suggesting that prostaglandins released from lymphocyte-activated macrophages might be involved in the defective induction of T-suppressor cell activity in rats with adjuvant arthritis.