Glycosylation of the T-cell antigen-specific receptor and its potential role in lectin-mediated cytotoxicity.

AUTOR(ES)

Hubbard, S C

RESUMO

Cytotoxic T lymphocytes (CTLs) normally destroy only those cells ("target cells") whose surface antigens they recognize. However, in the presence of lectins such as Con A, CTLs destroy virtually any cell, regardless of its antigens. The oligosaccharides of the T-cell antigen-specific receptor, a dimeric surface glycoprotein composed of disulfide-linked alpha and beta subunits, are of interest because of their potential involvement in this lectin-dependent cytotoxic activity. We report here that three or four asparagine-linked oligosaccharides could be enzymatically removed from each of the receptor subunits expressed by a cloned line of murine CTLs (clone 2C), consistent with the presence of glycosylation sites deduced from cDNA sequences of the alpha and beta genes expressed in this clone. All the N-linked glycans on the alpha subunit were of the complex type (i.e., resistant to endoglycosidase H), but the beta subunit carried two or three endoglycosidase H-sensitive (high-mannose) oligosaccharides. High-mannose glycans can bind tightly to Con A and, indeed, this lectin was found to bind specifically to solubilized 2C T-cell receptor. The Con A-dependent cytotoxic activity of clone 2C, but not of other CTL clones, was inhibited by a monoclonal antibody (1B2) that is specific for the T-cell receptor of clone 2C. Antibody 1B2 also inhibited clone 2C cytotoxicity mediated by phytohemagglutinin, lentil-lectin, and wheat-germ agglutinin. These results suggest that, although lectin-dependent lysis of target cells by CTLs is antigen nonspecific, the cytolytic activity can be triggered by binding of the lectin to the T-cell antigen-specific receptor.

Documentos Relacionados

• T-cell receptor-negative natural killer cells display antigen-specific cytotoxicity for microvascular endothelial cells.
• T-cell receptor alpha chain plays a critical role in antigen-specific suppressor cell function.
• Specific inhibition of cell-surface T-cell receptor expression by antisense oligodeoxynucleotides and its effect on the production of an antigen-specific regulatory T-cell factor.
• Messenger RNA for an antigen-specific binding molecule from an antigen-specific T-cell hybrid.
• Antigen-specific human T-cell hybridomas with helper activity.