title: The immunobiology of placentation.
abstract: A review of the current theories on the nature of the placental allograft and the evolution of placentation in the presence of a cellular immune response highlights the inability of current hypotheses to explain the success of both invertebrate and vertebrate placentation. Only one theory -- "the anatomical separation of the fetus from the mother" -- appears relevant. How this separation might develop during implantation is discussed.
mesh_terms: D000818:Animals; D000917:Antibody Formation; D001775:Blood Circulation; D010064:Embryo Implantation; D004622:Embryo, Mammalian / Q000502:physiology; D005260:Female; D005306:Fertilization; D006082:Graft Enhancement, Immunologic; D006649:Histocompatibility Antigens / Q000276:immunology; D006801:Humans; D007109:Immunity; D007111:Immunity, Cellular; D010802:Phylogeny; D010920:Placenta / Q000637:transplantation; D010929:Placentation; D011247:Pregnancy; D014184:Transplantation, Homologous; D014327:Trophoblasts / Q000276:immunology; D014599:Uterus / Q000276:immunology
chemical_list: D006649:Histocompatibility Antigens