title: Overexpression of branched O-linked oligosaccharides on T cell surface glycoproteins impairs humoral immune responses in transgenic mice.
abstract: The aberrant expression of core 2 O-glycans on T cell surface glycoproteins has been associated with various immunodeficient syndromes such as Wiskott-Aldrich syndrome and AIDS. To determine the effect of this aberrant expression of core 2 O-glycans on immune responses, we previously generated transgenic mice overexpressing core 2 beta-1,6-N-acetylglucosaminyltransferase (C2GnT) in T cells, and demonstrated that T cell primary immune responses mediated through interaction between T cells and antigen-presenting cells are impaired in the transgenic mice (Tsuboi, S., and Fukuda, M. (1997) EMBO J. 16, 6364-6373). In this study, we determined whether overexpression of core 2 oligosaccharides on T cells leads to impaired humoral immune responses by B cells using the same transgenic mice. When T cells were activated, both T and B cells from the transgenic and control mice expressed an equivalent amount of CD40L and CD40, which are, respectively, the receptor and counter-receptor for the interaction between T and B cells. However, activated T cells from the transgenic mice induced B cell proliferation less efficiently than those from control mice, regardless of whether B cells were isolated from control or the transgenic mice. This suggests that overexpression of core 2 O-glycans on T cell surface glycoproteins renders T cell-B cell interaction inefficient. Moreover, in the transgenic mice both immunoglobulin isotype switching and germinal center formation were also impaired. Taken together, these results indicate that aberrant expression of core 2 O-glycans on T cell surface glycoproteins results in impaired humoral immune responses due to an impaired interaction between T and B cells.
authors.affiliation: Glycobiology Program, La Jolla Cancer Research Center, The Burnham Institute, La Jolla, California 92037, USA.
authors.forename: S
authors.initials: S
authors.lastname: Tsuboi
authors.forename: M
authors.initials: M
authors.lastname: Fukuda
mesh_terms: D000818:Animals; D000917:Antibody Formation; D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D015153:Blotting, Western; D023201:CD40 Ligand; D016466:CHO Cells; D006224:Cricetinae; D017578:Immunoglobulin Class Switching; D008213:Lymphocyte Activation; D008562:Membrane Glycoproteins; D051379:Mice; D008822:Mice, Transgenic; D017351:N-Acetylglucosaminyltransferases / Q000378:metabolism*; D009844:Oligosaccharides / Q000096:biosynthesis*; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism
chemical_list: D008562:Membrane Glycoproteins; D009844:Oligosaccharides; D023201:CD40 Ligand; D017351:N-Acetylglucosaminyltransferases; C053024:beta-1,3-galactosyl-O-glycosyl-glycoprotein beta-1,6-acetylglucosaminyl transferase