Antibodies against sialyloligosaccharides coupled to protein.

The beta-(p-aminophenyl)ethylamine derivatives of sialyloligosaccharides can be coupled to proteins via their phenylisothiocyanate intermediates under conditions that preserve labile sugar linkages. Bovine serum albumin containing 10 to 40 mol of oligosaccharides/mol of protein and keyhole limpet hemocyanin containing 1,100 mol of oligosaccharide/mol of protein have been prepared with the following oligosaccharides: Neu-NAc alpha 2-3Gal beta 1-4Glc, NeuNAc alpha 2-6Gal beta 1-4Glc, Neu-NAc alpha 2-6Gal beta 1-4GlcNAc beta 1-4Glc, Gal beta 1-3[Neu-NAc alpha 2-6]GlcNAc beta 1-4Glc, and NeuNAc alpha 2-3Gal- beta 1-3[NeuNAc alpha 2-6]GlcNAc beta 1-4Glc. Rabbits immunized with these synthetic glycoproteins produce antibodies directed against the oligosaccharides. The specificities of these antibodies are determined by comparing inhibitory activities of structurally related oligosaccharides in radioimmunoassay and by double diffusion analysis in agarose gels using oligosaccharide-protein conjugates as precipitating antigens. The antibodies distinguish positional isomers of sialic acid.