Fine specificity of a monoclonal anti-testicular cell antibody for glycolipids with terminal N-acetyl-D-glucosamine structure.

The specificity of a mouse anti-testicular cell monoclonal antibody, J1, was investigated. Previous studies suggested that N-acetyl-D-glucosamine (GlcNAc) was a constituent of the determinant recognized by J1. When the antibody was tested against a variety of purified glycolipids containing this saccharide in terminal, penultimate or internal positions, J1 reacted only with species expressing terminal GlcNAc. The influence of oligosaccharide chain length, branch substitution, and haptenic valence on J1 binding was examined using glycolipids prepared by a weak acid hydrolysis and exoglycosidase digestion of bovine I-active ganglioside. Degree of binding was inversely proportional to chain length and was proportional to hapten valence. Failure of J1 to bind partially deglycosylated transferrin implied binding preference for GlcNAc beta 1----3Gal over GlcNAc beta 1----2Man. Immunofluorescence analysis of J1 binding to human neutrophils failed to detect lactotriosylceramide on their surface, although this glycolipid has previously been isolated from these cells, suggesting that this structure exists in a cryptic or intracellular form. Binding results were consistent with J1 having low affinity for GlcNAc or GlcNAc beta 1----3Gal on a variety of lacto-series glycolipids.