title: Aberrant O-linked oligosaccharide biosynthesis in lymphocytes and platelets from patients with the Wiskott-Aldrich syndrome.
abstract: The Wiskott-Aldrich syndrome (WAS) is an X-linked recessive immunodeficiency affecting B lymphocytes, T lymphocytes, and platelets. Previous studies on lymphocytes from WAS patients have revealed that leu-kosialin (CD43), a cell-surface glycoprotein bearing approximately 90 O-linked oligosaccharide chains, shows an aberrant electrophoretic mobility. To determine whether this finding reflects a different pattern of O-linked glycosylation in WAS cells, we have compared healthy individuals and WAS patients with respect to glycosyltransferase activities in T lymphocytes, platelets, and Epstein-Barr virus (EBV)-immortalized B cell lines. Stimulation of peripheral T cells from normal individuals in vitro with anti-CD3 antibodies and interleukin-2 was associated with a 3-fold increase in UDP-GlcNAc:Gal beta 3GalNAc-R (GlcNAc to GalNAc) beta 6-N-acetylglucosaminyltransferase (core 2 GlcNAc-T) from 0.8 to 2.2 nmol/mg/h. In contrast, peripheral T lymphocytes from WAS patients showed an inversion of this phenotype with high core 2 GlcNAc-T activity in unstimulated cells (2.3 nmol/mg/h) and a 2-3-fold decrease in activity following stimulation. Core 2 GlcNAc-T activity was also three times higher in platelets from WAS patients than in normal platelets. Glycosyltransferase activities were measured in immortalized B cell lines established from WAS and normal subjects by infection with EBV. Core 2 GlcNAc-T was less than 0.4 nmol/mg/h in WAS EBV-B cell lines compared to 2.4 nmol/mg/h in EBV-B cell lines from healthy individuals, In contrast, CMP-SA:SA alpha 2-3Gal beta 1-3GalNAc-R (where SA represents sialyl (sialic acid to GalNAc) alpha 6-sialyltransferase II activity was 2.0 nmol/mg/h in the WAS EBV-B cell and less than .01 nmol/mg/h in EBV-B cell lines derived from normal subjects. Eleven other glycosyltransferase activities were measured and found to be similar in EBV-B cell lines from WAS and normal individuals. Polylactosamine sequences were much reduced in the O-linked oligosaccharides of CD43 from WAS EBV-B cells consistent with decreased core 2 GlcNAc-T activity and expression of core 1 oligosaccharides in the cells. In conclusion, B cells, T cells, and platelets in WAS patients show abnormal expression of two developmentally regulated glycosyltransferases, consistent with the idea that the WAS immunodeficiency is due to a failure of normal lymphocyte maturation.
authors.affiliation: Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada.
authors.forename: E A
authors.initials: EA
authors.lastname: Higgins
authors.forename: K A
authors.initials: KA
authors.lastname: Siminovitch
authors.forename: D L
authors.initials: DL
authors.lastname: Zhuang
authors.forename: I
authors.initials: I
authors.lastname: Brockhausen
authors.forename: J W
authors.initials: JW
authors.lastname: Dennis
mesh_terms: D000293:Adolescent; D000328:Adult; D001792:Blood Platelets / Q000201:enzymology / Q000378:metabolism*; D002648:Child; D002675:Child, Preschool; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D006602:Hexosyltransferases / Q000097:blood; D006801:Humans; D008213:Lymphocyte Activation; D009682:Magnetic Resonance Spectroscopy; D008861:Microsomes / Q000378:metabolism; D009844:Oligosaccharides / Q000096:biosynthesis*; D011233:Precipitin Tests; D012799:Sialyltransferases / Q000097:blood; D013601:T-Lymphocytes / Q000201:enzymology / Q000378:metabolism*; D014923:Wiskott-Aldrich Syndrome / Q000097:blood* / Q000503:physiopathology; D000094802:beta-D-Galactoside alpha 2-6-Sialyltransferase
chemical_list: D009844:Oligosaccharides; D006602:Hexosyltransferases; C018660:asparagine-N-glycosyltransferase; D012799:Sialyltransferases; D000094802:beta-D-Galactoside alpha 2-6-Sialyltransferase