CHARACTERIZATION OF NATURAL IGG ANTIBODY WITH ANTI-BETA-GALACTOSYL SPECIFICITY

It was demonstrated that the IgG with anti-alpha-galactosyl specificit y (anti-alpha-Gal IgG) occurs in normal human serum. Subsequently, we isolated the IgG with anti-beta-galactosyl specificity (anti-beta-Gal IgG) from normal human serum by affinity chromatography using lactose- Sepharose as affinity adsorbent (15). In this study, the carbohydrate specificity of anti-beta-Gal IgG was further examined. Purified human anti-beta-Gal IgG showed distinct specificity with the structure of Ga l beta 1-4Glc in oligosaccharide inhibition experiments. However, it d id not react with Gal beta 1-4Glc beta 1-1'Cer nor NeuAc alpha 2-3Gal beta 1-4Glc beta 1-1'Cer(GM3) in thin-layer chromatography (TLC), sug gesting that besides Gal beta 1-4Glc, more inner structure may be impo rtant. The ELISA for anti-beta-Gal IgG and anti-alpha-Gal IgG using s ynthetic lactose or melibiose-BSA conjugates was developed, and the l evels of these antibodies in normal and patient sera were measured. Th eir concentrations were found to vary in the range of 10-280 mu g/ml a nd 10-220 mu g/ml, respectively, in normal subjects. Distinctly higher levels over these ranges were found in two terminal patients with mal ignant tumor. Anti-beta-Gal antibodies were also found in the sera fro m various non-primates. Purified calf anti-beta-Gal antibodies showed the same specificity as that of humans.