A new human trophoblast antigen isolated from immune complexes derived from placental blood and membranes.

Immune complexes were prepared from human trophoblast membranes, placental blood serum, non-pregnant female serum and normal male serum by precipitation, gel filtration and affinity chromatography. The purified complexes were subjected to analysis by SDS-PAGE and one common antigenic species was identified. This antigen (mol. wt. 82.8 +/- 2.4 K) was designated the putative trophoblast antigen (TA) and shown to exhibit discrete antigenic homology with human immunoglobulin and HLA molecules.