Identification of terminal N-acetylglucosamine residues of highly branched asparagine-linked oligosaccharides as immunoreactive domains of a chicken heterophile antigenic determinant

Abstract Chicken heterophile antigenic determinant (CHAD-1) has been previously found in medullary lymphocytes of the bursa and thymus as well as in some non-lymphoid cells by the immunoperoxidase method, using rabbit antiserum to a complete Freund's adjuvant (CFA) as the first antibody. In this work we demonstrated that absorption of anti-CFA serum with highly purified preparations of hen egg white glycoproteins (ovomucoid, ovoinhibitor, ovalbumin) or chicken orosomucoid completely blocked immunoperoxidase staining for CHAD-1. Treatment of these glycoproteins with β- N -acetylglucosaminidase suppressed their capacity to inhibit this staining. Absorption of anti-CFA serum with asparagine-linked glycopeptides which have the mannose α1,3 arm disubstituted by GlcNAc residues and which have another GlcNAc residue linked β 1,4 to the β-linked mannose of the core also inhibited staining for CHAD-1. These data indicated that highly branched asparagine-linked oligosaccharides with terminal GlcNAc residues β-linked to mannose represent immunoreactive domains of CHAD-1.