Glycosylation and Placental Transport of Immunoglobulin G

Abstract

In order to investigate the relationship between the changes in glycosylation and the placental materno-fetal transport of Immunoglobulin G (IgG), glycosylation profiles of IgG from healthy pregnant women and their umbilical cords at delivery were compared by use of a recently established high-performance liquid chromatography (HPLC) method. From the results of neutral oligosaccharide analysis, the digalactosyl IgG glycoform (G₂) was markedly increased in pregnant women as compared with that in age-matched controls. Furthermore, the quantity of the digalactosyl glycoform in the umbilical cord was found to be higher than that in the mother. These findings demonstrate the existence of a placental selective transport with a preference for a digalactosyl oligosaccharide-linked IgG molecule. Concerning IgG sialo-oligosaccharides, however, no selective transport was observed between mother and umbilical cord. The mechanism and clinical importance of greater galactosylation in IgG still remain unclear, but we suggest that the relationship between changes in IgG galactosylation and the placental selective transport deserves further attention.