Allotypic trophoblast—lymphocyte cross-reactive (TLX) cell surface antigens

Evidence is presented for the presence of trophoblast-lymphocyte cross-reactive (TLX) cell surface antigens. Complement-dependent lymphocytotoxicity studies with antitrophoblast sera (Ce) raised to ten separate placentas showed variable reaction patterns on peripheral blood leukocytes isolated from 30 random HLA-typed donors. No correlation with any known antigens of the major histocompatibility complex was evident. Absorption studies with chromatographically prepared fractions of solubilized trophoblast membranes from individual placentas and absorptions with both normal and transformed lymphoid cells removed cytotoxicity from some but not other Ce antisera when tested on a single donor, thus providing serological evidence for allotypic variation among the TLX antigens.