Prostaglandin production and suppressor cell induction in transfusion-induced immune suppression.

Two models were used to examine the role of prostaglandin (PGE) in the inductive phase of transfusion-induced suppression. First, it was observed that post-operative allogeneic third-party blood transfusion resulted in prolonged major histocompatibility complex (MHC)-compatible rat heart allograft survival. Additionally, pretransplant antigen-specific allogeneic transfusion decreased graft-versus-host (GVH) reactivity in mice. An inhibitor of PGE synthesis, indomethacin, blocked transfusion-induced suppression when it was administered to either transfused rat heart recipients, or graft-versus-host responder mice. Neutralization of endogenous PGE by anti-PGE antibody also blocked allogeneic blood induced suppression. Allogeneic-blood-induced splenic suppressor cells down-regulated normal GVH responsiveness, and appeared to be generated via a prostaglandin-dependent pathway.