Non-specifically bound immunoglobulins on mouse placental cells.

There seem to be some similarities between mechanisms employed by embryos and cancer cells from the maternal or tumor bearer's immune system. In the present study, we investigated the presence of hemagglutinins on placental cells and their relationship to circulating antibodies in mice immunized against sheep erythrocytes before mating. The results obtained demonstrated that placental cells may fix large quantities of maternal immunoglobulins. The hemagglutinins are probably fixed on placental cells by the Fc, since the combining sites of the antibody were free and able to react with the antigen in the "rosette" test. It was also demonstrated that placental tissue may fix up to 1/4 of the maternal circulating antibodies, while only 1/200 of them were transmitted to the fetuses. Some theoretical implications of the presence in the placenta of antibodies not directed against feto-placental antigens are also discussed.