Abstract
Lymphocyte homing to secondary lymphoid organs has been extensively studied during the past quarter century. The first stage of lymphocyte homing is known as “lymphocyte rolling,” which occurs in high endothelial venules (HEV) of lymph nodes. Lymphocyte rolling in HEV of peripheral lymph nodes is dependent on L-selectin expressed on lymphocytes. The L-selectin ligand is comprised of sialylated sulfated oligosaccharide, 6-sulfo sialyl Lewis X (sLeX). For many years, the MECA-79 monoclonal antibody, the epitope of which was subsequently shown to be an O-linked oligosacchride, has been used to stain HEV and the relationship between the MECA-79 antigen and L-selectin ligands has been discussed. Recently, targeted disruption of glycosyltransferases and related enzymes revealed the critical structure of L-selectin ligands and the significance of the MECA-79 antigen. This paper describes the structural basis of L-selectin ligand oligosaccharides and MECA-79 antigen.
