Structural changes in the N-linked sugar chains of serum immunoglobulin G of HTLV-I transgenic mice.

IgGs were purified from the sera of HTLV-I transgenic and nontransgenic mice. Comparative studies of the N-linked sugar chains released by hydrazinolysis revealed that their structures of transgenic IgG are quite different from those of nontransgenic IgG. Although both IgGs contained biantennary complex-type oligosaccharides, transgenic IgG had more agalactosylated forms (45%) than those from nontransgenic IgG (28%), just as was found in patients with rheumatoid arthritis (RA). Since these transgenic mice express arthritis similar to RA, it will be a useful model to investigate the relationship between the galactosylation of IgG and the development of RA.