title: Early murine T-lymphocyte activation is accompanied by a switch from N-Glycolyl- to N-acetyl-neuraminic acid and generation of ligands for siglec-E.
abstract: It is well established that murine T-lymphocyte activation is accompanied by major changes in cell-surface sialylation, potentially influencing interactions with sialic acid-binding immunoglobulin-like lectins (siglecs). In the present study, we analyzed early activation of murine CD4+ and CD8+ T-lymphocytes at 24 h. We observed a striking and selective up-regulation in the binding of a recombinant soluble form of siglec-E, an inhibitory siglec, which is expressed on several myeloid cell types including antigen-presenting dendritic cells. In contrast, much lower levels of T cell binding were observed with other siglecs, including sialoadhesin, CD22, and siglec-F and the plant lectins Maackia amurensis leukoagglutinin and Sambucus nigra agglutinin. By mass spectrometry, the sialic acid content of 24-h-activated CD4+ and CD8+ T-lymphocytes exhibited an increased proportion of N-acetyl-neuraminic acid (NeuAc) to N-glycolyl-neuraminic acid (NeuGc) in N-glycans. Reduced levels of NeuGc on the surface of activated T cells were demonstrated using an antibody specific for NeuGc and the expression levels of the gene encoding NeuAc- to NeuGc-converting enzyme, CMP-NeuAc hydroxylase, were also reduced. Siglec-E bound a wide range of sialylated structures in glycan arrays, had a preference for NeuAc versus NeuGc-terminated sequences and could recognize a set of sialoglycoproteins that included CD45, in lysates from activated T-lymphocytes. Collectively, these results show that early in T cell activation, glycan remodelling involves a switch from NeuGc- to NeuAc-terminating oligosaccharides on cell surface glycoproteins. This is associated with a strong up-regulation of siglec-E ligands, which may be important in promoting cellular interactions between early activated T-lymphocytes and myeloid cells expressing this inhibitory receptor.
authors.affiliation: Division of Cell Signalling and Immunology, Wellcome Trust Biocentre, University of Dundee, Dundee DD1 5EH, United Kingdom.
authors.forename: Pierre
authors.initials: P
authors.lastname: Redelinghuys
authors.forename: Aristotelis
authors.initials: A
authors.lastname: Antonopoulos
authors.forename: Yan
authors.initials: Y
authors.lastname: Liu
authors.forename: Maria A
authors.initials: MA
authors.lastname: Campanero-Rhodes
authors.forename: Emma
authors.initials: E
authors.lastname: McKenzie
authors.forename: Stuart M
authors.initials: SM
authors.lastname: Haslam
authors.forename: Anne
authors.initials: A
authors.lastname: Dell
authors.forename: Ten
authors.initials: T
authors.lastname: Feizi
authors.forename: Paul R
authors.initials: PR
authors.lastname: Crocker
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000378:metabolism*; D000944:Antigens, Differentiation, B-Lymphocyte / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D003713:Dendritic Cells / Q000166:cytology; D006801:Humans; D037102:Lectins / Q000378:metabolism; D017493:Leukocyte Common Antigens / Q000096:biosynthesis; D008024:Ligands; D008213:Lymphocyte Activation; D013058:Mass Spectrometry / Q000379:methods; D051379:Mice; D008810:Mice, Inbred C57BL; D019158:N-Acetylneuraminic Acid / Q000378:metabolism*; D009438:Neuraminic Acids / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000378:metabolism; D051918:Sialic Acid Binding Ig-like Lectin 2 / Q000096:biosynthesis; D013601:T-Lymphocytes / Q000166:cytology*
chemical_list: D015703:Antigens, CD; D000944:Antigens, Differentiation, B-Lymphocyte; D037102:Lectins; D008024:Ligands; D009438:Neuraminic Acids; D011956:Receptors, Cell Surface; D051918:Sialic Acid Binding Ig-like Lectin 2; C422908:Siglece protein, mouse; C055213:saccharide-binding proteins; C032592:N-glycolylneuraminic acid; D017493:Leukocyte Common Antigens; D019158:N-Acetylneuraminic Acid