Suppression of secondary plaque-forming cell responses by rat splenic adherent cells: evidence for dependence on prostaglandin production.

Rat spleens normally contain adherent suppressor cells with macrophage-like characteristics. This paper presents data indicating that the activity of these cells, as measured by decreased secondary in vitro PFC responses to heterologous erythrocytes, is dependent upon the production of prostaglandins. PFC can be restored in vitro by the use of indomethacin and aspirin—different drugs which both inhibit prostaglandin synthesis among other cellular functions. An experimental drug, Ro3-1314, which has as its only known function the inhibition of prostaglandin synthesis, also acts similarly. The suppression relieved by these drugs can be restored by the addition of PGE².