Enhancement of the activities of glycosyltransferases involved in the biosynthesis of mucin-type sugar chains in autoimmune MRL LPR/LPR mouse T cells

Abstract

Lymph node (LN) T cells from autoimmune MRL/MpJ-Ipr/Ipr (lpr) mice and control MRL/MpJ-+ / + ( + / + ) mice were compared as to their cell surface lectin-binding sites and glycosyltransferase activities. T cells from enlarged LN of lpr mice expressed a higher amount of binding sites for lectins reactive to mucin-type sugar chains than normal +/+ mouse T cells. Correspondingly, glycosyltransferase activities involved in the biosynthesis of mucin-type sugar chains were higher in Ipr mouse T cells than in +/+ T cells. The activities of UDP- N-acetylgalactosamine (GalNAc):polypeptide GalNAc transferase and UDP-galactose (Gal):asialo bovine submaxillary mucin (BSM) Gal transferase were found to be elevated. The activity of UDP-Gal:asialo-agalacto transferrin Gal transferase, which is involved in the biosynthesis of complex type sugar chains, was also increased in Ipr mice but to a smaller extent than the mucin-type Gal transferase activities. An abnormality in sialyltransferase activity was also found in Ipr T cells.