Antigens of the human trophoblast plasma membrane.

Using purified plasma membranes of human syncytial trophoblast as immunogen, we have raised heterologous antisera which reacted by indirect immunohistological methods with the surface of the trophoblast. This antigenic activity appears to be absent from other adult and foetal tissues. Its absence from maternal sera and its resistance to mild detergents treatment suggest that it is intimately associated with the surface membrane of the syncytial trophoblast. This antigen was found to be immunologically different to a number of proteins, including those known to be produced by the trophoblast. The identification of this antigen may indicate a potential line of research for the immunological regulation of human fertility.