Adsorption of chain type–specific ABO antibodies on Sepharose‐linked A and B tetrasaccharides

Abstract

Antigen-specific removal of anti-A and anti-B on immunoadsorption columns carrying the blood group A and B trisaccharides is one important component of some protocols used in ABO-incompatible organ transplantation. Because ABO antibodies exist requiring parts of the core saccharide chain for binding, the anti-A and -B-binding capacity of individual and combined, Sepharose-linked Types 1 through 4 A and B tetrasaccharides with that of the A and B trisaccharides was compared. Sepharose-linked A and B tri- and tetrasaccharides were used to adsorb anti-A and -B from pooled blood group O serum. Remaining chain type-specific anti-A and -B were detected and quantified in enzyme-linked immunosorbent assays using wells coated with neoglycoproteins or recombinant mucins carrying A and B determinants on defined core saccharide chains. Significantly more anti-A Type 3- and 4-specific immunoglobulin (Ig)G remained after adsorption on the A trisaccharide and the A Type 1 and A Type 2 tetrasaccharide than after adsorption on the A Types 3 and 4 tetrasaccharides. Selective adsorption of chain type-specific IgG anti-B was detected on Sepharose-linked B tetrasaccharides. In contrast, there were no chain type-specific IgM anti-A or -B. A combination of the A or B tetrasaccharides adsorbed a larger fraction of the IgG anti-A and -B repertoires than the corresponding trisaccharides. There are chain type-specific anti-A and anti-B IgG, and an adsorber based on a combination of Types 1 through 4 A or B tetrasaccharides will be a more efficient adsorber than an adsorber based on the A or B trisaccharides.