Human immunoglobulin
G is known to contain 16 different biantennary complex-type asparagine-linked sugar chains, each of which occurs in a nonsialylated, monosialylated, or disialylated form. These oligosaccharides can be separated into 14 fractions by sequential affinity chromatography with Aleuria aurantia lectin (AAL)-Sepharose, RCAl20-WGO03, and E,-phytohemagglutinin-agarose columns. Twelve of them were found to contain a single oligosaccharide, while the fraction which passed through all three columns was shown to contain two oligosaccharides, GlcNAcBl + 2Mancul + 6(tGlcNAcj31 + 4)(GlcNAcj31 + 2Mancu 1 + 3)Manfil + 4GlcNAcfi 1 + 4GlcNAcor. The fraction, which bound to the AAL-Sepharose column and passed through the remaining two lectin columns, also contained two oligosaccharides, GlcNAcPl + 2Manal + 6(+GlcNAcfll + 4)(GlcNAcPl + 2Manal + 3)ManB 1 + 4GlcNAcP 1 + 4(Fuccu 1 + 6)GlcNAcor. These results indicated that serial affinity chromatography with the three lectin columns can be used effectively to detect changes in the sugar chains of IgG resulting from diseases such as rheumatoid arthritis. o 1987 Academic press, Inc.