Involvement of Both the N-Glycan-relevant and N-Glycan-irrelevant Structural Elements in the Recognition of Human Milk Lactoferrin by the 1CF11 Monoclonal Antibody

Abstract

Monoclonal antibody 1CF11 has been suggested to specifically recognize a certain carbohydrate epitope shared by glycoproteins in human external secretions. We examined the effect of cleaving the polypeptide backbone and removing N-linked oligosaccharides on the reactivity with 1CF11 of human milk lactoferrin (hLf) to elucidate the structural features of the 1CF11 epitope. We reveal by treating hLF with trypsin and/or N-glycosidase that both the N-glycan-relevant and N-glycan-irrelevant structural elements were involved in the recognition of hLf by 1CF11.

Non-Reducing Terminal Fucose within N-Linked Glycan Plays a Significant Role in the Recognition of Human Milk Lactoferrin by the 1CF11 Monoclonal Antibody

“…[7][8][9] We have recently revealed that both hLf and its tryptic digests, after being deglycosylated with N-glycosidase F, showed a significant reduction in their immunoreactivity, although the reaction was never lost. 10) This result clearly indicated that hLf carried two distinct structural elements, the N-glycan-relevant and the N-glycanirrelevant portions, that were recognized by 1CF11 in the molecule. Elucidation of their precise chemical requirements may allow us to fully comprehend the significance of glycosylation in the protein.…”