Allogeneic pregnancy as immunoabsorbent.

Experiments in the past have indicated that both human and rodent females undergo immune recognition of paternally derived antigens during pregnancy. Although the mechanisms that allow pregnancy to proceed in the face of this process have not yet been clarified, one simple possibility is that the paternal strain antigens are presented in a manner capable of neutralizing the maternal immune response. This predicts that allogeneically pregnant females should be capable of neutralizing passively administered cytotoxic anti-paternal strain antibody, with no consequent harm to the fetus. In this paper we demonstrate by two different methods that allogeneically pregnant mice rapidly absorb passively administered antibody directed against paternal strain major histocompatibility (H-2) antigens when compared to control mice pregnant by syngeneic or third party males. The possible sites where this absorption occurs are discussed.