GRANULOMATOUS HYPERSENSITIVITY TO SCHISTOSOMA-MANSONI ECC ANTIGENS INHUMAN SCHISTOSOMIASIS .5. A ROLE FOR PROSTAGLANDIN-INDUCED INHIBITIONOF IN-VITRO GRANULOMA-FORMATION

The prostaglandins (PG) al e known to regulate immune cell function(s) and participate in the progression of both acute and chronic inflamma tory reactions. Using an in vitro model of Schistosoma mansoni egg-ind uced hypersensitivity granulomas, we have delineated the role of immun e complexes (IC) in the induction and release of PG and their inhibito ry effects on granuloma development. The hypersensitivity-type granulo ma reaction to soluble egg antigen (SEA) was examined using a model of in vitro granuloma formation. Our results show that granuloma formati on was dramatically suppressed by the addition to the granuloma cultur es of IC, PGE(1), PGE(2), while PGF(2) alpha had no significant effect . The inhibition of the PG function was achieved by the introduction o f anti-PG antibodies that blocked suppression of granuloma formation. It appeals in this model system that IC may inhibit the activity of gr anuloma formation by stimulating the monocyte-macrophage lineage to re lease inhibitory mediators. Our results suggest that the prostaglandin s E series may be important in the generation and maintenance of suppr ession of the granulomatous inflammatory response to S. mansoni egg an tigens.