The stability of lymphocytic beta 1,4-galactosyltransferase expression during pregnancy and lactation

The authors used murine pregnancy as a model to investigate the regulation of IgG glycosylation. Pregnancy is associated with decreased levels of circulating IgG. The oligosaccharides on this IgG from late (day 15), but not early (day 8), pregnant Balb/c mice exhibited increased levels of terminal galactose. The levels remained elevated 8 days post-partum in lactating mice. Nonetheless, splenic beta 1, 4-GalTase mRNA and Enzyme activity remained relatively constant throughout pregnancy and into lactation. This was in contrast to a pregnancy-associated increase in mammary gland beta 1,4-GalTase mRNA. Thus the increased IgG galactose levels seen in pregnancy are regulated by mechanisms which are independent of transcriptional control of beta 1,4-GalTase expression.