Novel carbohydrate specificity of monoclonal antibody 91.9H prepared against human colonic sulfomucin: Recognition of sulfo-Lewis a structure

Monoclonal antibody (mAb) 91.9H was previously prepared against partially p urified human colonic sulfomucins. The epitope was detected in normal colon ic mucosa and primary and metastatic colorectal carcinoma in decreasing ord er of magnitude, In the present study, this antibody was shown to recognize sulfo-Le(a) structure, HSO3-3Gal beta 1-3(Fuc alpha 1-4)GlcNAc. Interactio ns between mAb 91.9H and synthetic oligosaccharides conjugated with biotiny lated polyacrylamide carrier were examined by a biosensor based on surface plasmon resonance and by enzyme-linked immunosorbent assays. This mAb bound to sulfo-Le(a) but not to sulfo-Le(X), Le(a) Le(X),sialyl-Le(a) or sialyl- Le(X). Sulfo-Lea oligosaccharides decreased its binding affinity with mAb 9 1.9H after periodate oxidation of its fucose residue, Immunohistochemical s tudy showed a strong binding of mAb 91.9H to goblet cells in human colonic epithelia of Lewis-positive individuals but a trace binding in Lewis-negati ve individuals, confirming the specificity of this antibody toward structur es containing a fucosylated type 1 backbone. (C) 1998 Academic Press.