The possible role of prostaglandins in mediating immune suppression by nonspecific T suppressor cells

Abstract

Nonadherent splenic lymphoid cells from tumor-bearing animals exhibit a poor primary in vitro plaque-forming cell (PFC) response to SRBC. This is attributable to the presence, in this population, of a T suppressor cell. This nonadherent population suppressed the in vitro anti-SRBC PFC response of normal spleen cells (NSC). This nonspecific suppressive effect was eliminated by adding indomethacin, a prostaglandin synthetase inhibitor, to the in vitro cultures. These effects were seen at indomethacin concentrations which have no direct effect on the NSC response. When exogenous prostaglandins were added to NSC cultures plus SRBC, prostaglandins PGE 1 and PGE 2 were shown to markedly inhibit the PFC response at a wide range of concentrations, whereas PGA 1, PGF 1α, and PGF 2α were inhibitory only at the highest concentrations tested.