Definition of three species-specific monoclonal antibodies recognizing antigenic structures present on human embryonal carcinoma cells which undergo modulation during in vitro differentiation.

Three novel species-specific monoclonal antibodies 5.1.H, 8.7.D and 13.7.A raised against semi-purified detergent solubilized fractions of the Tera 1 embryonal carcinoma (EC) cell line are restricted in their in vitro distribution to undifferentiated human EC cell lines. Competition experiments have established that distinct antigenic specificities are seen by the 3 different monoclonal antibodies. All 3 antigens 5.1.H, 8.7.D and 13.7.A, defined by these monoclonal antibodies, undergo developmental regulation and cease to be expressed on Tera 2 clones 5 and 12 after retinoic-acid-induced differentiation and on LICR LON HT 39/7 cells after phorbol-ester-induced differentiation. These results taken together with the extremely limited in vivo tissue distribution of the defined antigens suggest that the 5.1.H, 8.7.D and 13.7.A monoclonal antibodies define distinct onco-foetal antigens.