Binding of galectin-1 (gal-1) to the Thomsen-Friedenreich (TF) antigen on trophoblast cells and inhibition of proliferation of trophoblast tumor cells in vitro by gal-1 or an anti-TF antibody

Galectin-1 (gal-1), a member of the mammalian beta-galactoside-binding proteins, recognizes preferentially Gal beta 1-4GlcNAc sequences of several cell surface oligosaccharides. We demonstrate histochemically that the lectin recognizes appropriate glycotopes on the syncytiotrophoblast and extravillous trophoblast layer from second trimester human placenta and on BeWo chorion carcinoma cells. Gal-1 binding to BeWo cells was diminished by the Thomsen-Friedreich (TF)-disaccha-ride (Gal beta 1-3GalNAc-) conjugated to polyacrylamide (TF-PAA). Gal-1 also inhibited BeWo cell proliferation in a concentration-dependent manner. Similar antipro-liferative effects were also observed with an anti-TF monoclonal antibody (mAb, A78-G/A7). Therefore, we conclude that ligation of Gal beta 1-4GlcNAc and Gal beta 1-3GalNAc epitopes on BeWo cells may have regulatory effects on cell proliferation.