title: Human TCR-gamma/delta alloreactive response to HLA-DR molecules. Comparison with response of TCR-alpha/beta.
abstract: We have analyzed the human gamma/delta T cell alloreactive response to class II HLA-DR molecules and attempted to compare this response with that mediated by the TCR-alpha/beta counterparts. Several gamma/delta CTL clones from a healthy individual were generated in mixed lymphocyte reactions against an EBV-transformed B cell line termed E418. Fine specificity and primary TCR structure of 10 representative clones (all CD4- CD8 +/-) were then determined. Functional studies, with the use of B cell lines homozygous for HLA-DR (DR1-10), indicated that all gamma/delta T cell clones specifically reacted with HLA-DR2 molecules. In addition, five clones were able to cross-react with subtypes of HLA-DR8. Extended panel target experiments, including lymphoblastoid cells expressing various HLA-DR2 subtypes, showed that the T cell clones displayed distinct fine specificities. Clones with broad (Dw2, Dw12, Dw21, Dw8.1, and Dw8.2) or in contrast, more restricted (DRB1*1501 or DRB1*1503) specificity were identified. Furthermore, amino acid substitutions at predicted peptide binding site position 30 and TCR-interacting position 67 of the DRB*1 beta-chain seemed to affect alloresponse of some T cell clones. With respect to TCR-gamma/delta structure, diversity in gene segment usage was observed, with the predominance of T cells using a V3-J gamma 2/V1-J delta 1+ receptor. A smaller fraction of the cells expressed TCR comprising V gamma 9 and V delta 1 regions. In contrast, the V delta 3 gene segment was used by a minority of the cells, and the V delta 2 was not expressed by any T cell clone. Together, the present data indicate that similarly to TCR-alpha/beta, human TCR-gamma/delta lymphocytes may recognize in a highly specific fashion a particular HLA-DR heterodimer. T cell clones cross-reacting with other HLA-DR molecules were also identified. Despite some degree of heterogeneity, V gene segment use by alloreactive clones seemed to be nonrandom. No obvious correlation between TCR gene use and HLA-DR alloreactivity could be identified. Moreover, our results suggest that similarly to TCR-alpha/beta cells, foreign MHC-bound peptides may contribute to TCR-gamma/delta alloreactive response.
authors.affiliation: Laboratory of Cellular Immunology, INSERM U333, Gustave Roussy Institute, Villejuif, France.
authors.forename: C
authors.initials: C
authors.lastname: Flament
authors.forename: A
authors.initials: A
authors.lastname: Benmerah
authors.forename: M
authors.initials: M
authors.lastname: Bonneville
authors.forename: F
authors.initials: F
authors.lastname: Triebel
authors.forename: F
authors.initials: F
authors.lastname: Mami-Chouaib
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002478:Cells, Cultured; D002999:Clone Cells; D003602:Cytotoxicity, Immunologic; D016694:Gene Rearrangement, delta-Chain T-Cell Antigen Receptor; D015334:Gene Rearrangement, gamma-Chain T-Cell Antigen Receptor; D006684:HLA-DR Antigens / Q000276:immunology*; D006801:Humans; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000276:immunology; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000235:genetics / Q000276:immunology*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D013329:Structure-Activity Relationship; D016176:T-Lymphocyte Subsets / Q000276:immunology*
chemical_list: D006684:HLA-DR Antigens; D016693:Receptors, Antigen, T-Cell, alpha-beta; D016692:Receptors, Antigen, T-Cell, gamma-delta