Document 0541
 DOCN  M9460541
 TI    Altered sialylation of CD45 in HIV-1-infected T lymphocytes.
 DT    9404
 AU    Lefebvre JC; Giordanengo V; Doglio A; Cagnon L; Breittmayer JP; Peyron
       JF; Lesimple J; Laboratoire de Virologie, U.E.R. de Medecine, Nice,
       France.
 SO    Virology. 1994 Mar;199(2):265-74. Unique Identifier : AIDSLINE
       MED/94167860
 AB    Immunodeficiency caused by HIV infection probably results from profound
       dysregulation of normal T lymphocyte properties by the virus. Despite
       description of the virus cytopathicity and numerous modifications in T
       cell functions, such as perturbation of antigen receptor signaling, CD4
       downregulation, and induction of apoptosis, the precise mechanisms
       underlying the disruption of normal immune responses have not yet been
       elucidated. In the present study, we show that HIV-1-infected
       lymphocytes of the CEM cell line (either latent or virus-producing) and
       HIV-1-infected CD4+ lymphocytes have several membrane proteins with
       altered glycosylation patterns. Using lectins with specificity for
       different carbohydrate moieties, we could demonstrate the presence of
       two exposed nonsialylated disaccharides: a terminal Gal beta 1-->3GalNAc
       and a terminal Gal beta 1-->4GlcNAc. In particular, CD45, one of the
       major T cell glycoproteins, appeared to be partially sialylated on N-
       and O-linked carbohydrate moieties. Concerning the latter, PNA lectin
       which recognizes nonsialylated terminal Gal beta 1-->3GalNAc might
       precipitate up to 75% of the total tyrosine phosphatase activity
       displayed by CD45 molecules from one latently HIV-1-infected CEM cell
       line. Since CD45 glycoproteins are thought to play an important
       regulatory role in cell-to-cell interactions owing to their variable
       extracellular region and because they may regulate membrane signaling
       through their intracellular phosphatase domains, we suggest that these
       altered CD45 molecules may present an abnormal signal for natural
       ligands such as the B-cell-specific surface receptor CD22, thus
       perturbing the normal immune response in HIV-1-infected individuals.
 DE    Antigens, CD45/*BIOSYNTHESIS/METABOLISM  Carbohydrate Sequence  Cells,
       Cultured  Glycosylation  *HIV-1  Molecular Sequence Data
       Protein-Tyrosine-Phosphatase/METABOLISM
       Sialoglycoproteins/*BIOSYNTHESIS/METABOLISM  Support, Non-U.S. Gov't
       T-Lymphocytes/*METABOLISM/*MICROBIOLOGY  JOURNAL ARTICLE

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