Structural changes in the oligosaccharide chains of IgG in autoimmune MRL/Mp-lpr/lpr mice.
The structures of the asparagine-linked oligosaccharide chains of IgG from autoimmune arthritic MRL/Mp-lpr/lpr (MRL-lpr/lpr) mice and control MRL/Mp(-)+/+ (MRL(-)+/+) mice were investigated. Two subpopulations of IgG, M1-I and M1-II, were obtained from serum of MRL-lpr/lpr mice by column chromatography on protein A-Sepharose CL-4B. Although M1-I did not bind to the column, its elution was retarded, whereas M1-II was bound and was eluted in acidic buffer. IgG (Mn) from MRL(-)+/+ mice showed the same chromatographic behavior as M1-II. The structures of oligosaccharide chains liberated quantitatively by hydrazinolysis from IgG samples Mn, M1-I, M1-II, and a pooled mixture (M1) of M1-I and M1-II were determined by sequential exoglycosidase digestion, lectin (RCA120) affinity HPLC, and by methylation analysis. Their oligosaccharide structures were the same and shown to be biantennary complex-type chains +/- Gal beta 1----4GlcNAc beta 1----2Man alpha 1----6(+/- Gal beta 1----4GlcNAc beta 1----2Man alpha 1----3)Man beta 1----4GlcNAc beta 1----4(+/- Fuc alpha 1----6)GlcNAc. The proportion of each oligosaccharide in Mn and M1-II was the same but differed from that in M1-I where the degree of the galactosylation was significantly decreased which caused the change in the oligosaccharide pattern of total serum IgG (M1) of autoimmune MRL-lpr/lpr mice. This phenomenon, which is also found in total serum IgG of patients with rheumatoid arthritis, suggests that alteration of oligosaccharides in IgG may be a common feature in animals which develop arthritis with the production of rheumatoid factor regardless of species.
Mizuochi
T
T
Division of Biomedical Polymer Science, Fujita Health University School of Medicine, Aichi, Japan.
Hamako
J
J
Nose
M
M
Titani
K
K
D000818:Animals; D001172:Arthritis, Rheumatoid / Q000276:immunology*; D001327:Autoimmune Diseases / Q000276:immunology*; D002240:Carbohydrate Sequence; D002846:Chromatography, Affinity; D006023:Glycoproteins / Q000378:metabolism*; D006031:Glycosylation; D007074:Immunoglobulin G / Q000302:isolation & purification; D008180:Lupus Erythematosus, Systemic / Q000276:immunology*; D051379:Mice; D008817:Mice, Mutant Strains; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000032:analysis*; D011499:Protein Processing, Post-Translational; D013205:Staphylococcal Protein A
D006023:Glycoproteins; D007074:Immunoglobulin G; D009844:Oligosaccharides; D013205:Staphylococcal Protein A