title: Allogeneic responses in vitro induced by fetomaternal alloimmunization.
abstract: The present study was undertaken in order to determine what type(s) of pregnancy-induced allogeneic reaction could alter MLC (mixed lymphocyte culture) reactivity in routine HLA-D typing of lymphocytes in multiparous women (MW) possessing antibodies against paternal HLA-DR antigens. Unresponsiveness to homozygous typing cells (HTC) representing a paternal and probably fetal HLA-DR determinant was frequently observed. Kinetics experiments ruled out an early secondary proliferative response to HTC representing the paternal HLA-D determinant, which would be missed in a classical long-term mixed lymphocyte culture. Direct cytotoxicity against paternal or panel target cells was not always associated with inhibition of proliferative response to the same stimulator cell. Specific anti-HLA-DR blocking activity (antibodies?) in the supernates of restimulation reactions of lymphocytes from MW could be responsible for this inhibitory effect. Moreover, the study points to the existence of suppressor cells in the immunized MW acting independently of specific restimulation. The in vitro suppression appeared to be selective, restricted to cells sharing HLA-D linked structures with the suppressor cells, and suggests that auto-regulator mechanisms could be induced in pregnancy in order to modulate antibody production.
mesh_terms: D000906:Antibodies; D001667:Binding, Competitive; D003602:Cytotoxicity, Immunologic; D005260:Female; D006680:HLA Antigens; D006684:HLA-DR Antigens; D000949:Histocompatibility Antigens Class II; D006801:Humans; D007108:Immune Tolerance; D007114:Immunization; D066298:In Vitro Techniques; D007959:Lymphocyte Culture Test, Mixed; D008431:Maternal-Fetal Exchange; D011247:Pregnancy; D050378:T-Lymphocytes, Regulatory / Q000276:immunology
chemical_list: D000906:Antibodies; D006680:HLA Antigens; D006684:HLA-DR Antigens; D000949:Histocompatibility Antigens Class II