A carbohydrate epitope defined by monoclonal antibody VC1.1 is found on N-CAM and other cell adhesion molecules

VC1.1 is a monoclonal antibody that stains the surfaces of neuronal subsets in the brain. Previous work showed that VC1.1 recognizes 3 polypeptide bands with molecular weights of 95-105 kDa, 140 kDa and 170 kDa and two high molecular weight proteoglycans with weights of approximately 680 and 650-700 kDa. The heterogeneity and molecular weight range of these bands suggested that VC1.1 might recognize a carbohydrate moiety associated with a family of cell surface molecules. It had been previously demonstrated that a separate monoclonal antibody, HNK-1 also recognized a cell surface associated epitope characterized as a sulfate- and glucuronic acid-containing N-linked carbohydrate. This epitope has been shown to be present on members of the N-CAM adhesion molecule family. In this report, we demonstrate that VC1.1 recognizes an N-linked carbohydrate group that is attached to myelin-associated glycoprotein and N-CAM. Immunocytochemical and biochemical comparisons of VC1.1 and HNK-1 staining in rat and cat brain indicate that these two antibodies probably recognize overlapping, or identical carbohydrate epitopes.