SULFATED SIALYL-LEWIS-X, THE PUTATIVE L-SELECTIN LIGAND, DETECTED ON ENDOTHELIAL-CELLS OF HIGH ENDOTHELIAL VENULES BY A DISTINCT SET OF ANTI-SIALYL-LEWIS-X ANTIBODIES

Endothelial cells of high endothelial venules (HEV) in human periphera l lymph nodes expressed a distinct type of sialyl Lewis X antigen, whi ch was detected preferentially with a set of anti-sialyl Lewis X antib odies, 2F3, 2H5 and HECA-452 in immunohistochemistry, while another se t of anti-sialyl Lewis X antibodies, FH-6 and CSLEX-1, failed to detec t it. The adhesion of cells expressing L-selectin to HEV was inhibited by members of the former set of antibodies in Stamper-Woodruff assays performed on frozen sections of human peripheral lymph nodes. Transfe ction of a cultured endothelial cell line with a human alpha 1-->3 fuc osyltransferase, Fuc-T VII, resulted in the expression of a distinct t ype of sialyl Lewis X antigen having the reactivity similar to that of HEV; i.e., the antigen appearing on the transfectant clone was detect able only with the set of 2F3, 2H5 and HECA-452, but not with the set of FH-6 and CSLEX-1. Treatment of transfectant cells with sodium chlor ate, a metabolic inhibitor of sulfation, resulted in reactivity to the members of the latter set of antibodies, suggesting that sulfation of sialyl Lewis X moiety was the cause of the discrepancy in the reactiv ity of the anti-sialyl Lewis X antibodies. When tested against various authentic sulfated sialyl Lewis X determinants,g-sulfo sialyl Lewis X and 6,6'-bis-sulfo sialyl Lewis X were found to be reactive to the an tibodies, 2F3, 2H5 and HECA-452, but not with antibodies FH-6 and CSLE X-1, suggesting that the distinct type of sialyl Lewis X determinant o n the HEV endothelial cells and Fuc-T VII-transfected endothelial cell clone are mainly 6-sulfo and/or 6,6'-bis-sulfo sialyl Lewis X determi nants. (C) 1997 Academic Press.