Antisperm Antibody-Mediated Alterations in the Cellular Activity of Human Trophoblast Cells in Culture

Abstract

Immune recognition of the fetus is well documented, yet the immunological basis of pregnancy loss awaits elucidation. Identification of trophoblast membrane epitopes as non-self either by preformed immunoglobulins or by circulating immunocompetent cells would lead to immunological rejection of the tissue. Such an event may occur in cases of cross-reacting antibodies developed as a consequence of exposure of sperm surface antigens. This hypothesis was tested by developing specific antibodies in rabbits against intact sperm surface antigens. These were subjected to different schedules of IgG purification and characterization. By means of nuclide precursor incorporation, the effect of antisperm antibody on DNA, RNA and protein synthesis of trophoblast cells in culture were studied. The results showed that the antibody inhibits incorporation into cells but after a delay of 72 hours some cells gradually recover. The interaction also led to a reduced rate of hCG production. Lysosomal enzyme activity was inhibited in the spent medium of antibody-treated cells but lysosome rich fractions showed no effect. This indicated that the major effect of the antibody was growth inhibitory rather than cytolytic.