ISOLATION AND PARTIAL CHARACTERIZATION OF THE PR AUTO-ANTIGEN DETERMINANTS

The determinants of the autoantigens Pr1-3 are associated with glycoconjugates of the membrane of human erythrocytes and other cells. They were split off from the peptide skeleton of the major sialoglycoprotein by alkaline hydrolysis and simultaneous reduction of the arising aldehyde functions with NaBH4. After dialysis of the cleavage products, oligosaccharides and glycopeptide fractions were obtained which displayed considerable heterogeneity in high performance thin-layer chromatography. The heterogeneity was confirmed by radio-thin-layer chromatography of labeled fractions obtained after reductive alkaline hydrolysis with NaB3H4. The fractions involved largely intact carbohydrate chains with GalNAcitol at the original reducing and NAN at the non-reducing end. The oligosaccharide fractions were Pr1-3-active in the hemagglutination inhibition test. The major compound was isolated by preparative thin-layer chromatography. The structure, determined after permethylation by combined application of gas-liquid chromatography/mass spectrometry, was NAN* 2-3 Gal 1-3 (NAN 2-6) GalNAcitol. This tetrasaccharide was Pr2-active and Pr1- Pr3-inactive. © 1979.