title: Highly restricted T-cell receptor repertoire in the CD8+ T-cell response against an HIV-1 epitope with a stereotypic amino acid substitution.
abstract: OBJECTIVE
  In peripheral blood mononuclear cells (PBMCs) from HIV-1-positive patients, we sought to identify CD8+ T-cell populations and the corresponding T-cell receptor (TCR) repertoires that react to an immunogenic cytotoxic T lymphocyte (CTL) epitope with or without an escape mutation.
  
  
  METHODS
  PBMCs from HLA-A*2402(A24)-positive patients were stimulated with peptides representing a wild-type CTL epitope in the HIV-1 Nef protein [Nef138-10(wt)] or an escape mutant with a Y to F (Y139F) substitution at the second position [Nef138-10(2F)]. Cultured PBMCs were stained with peptide-major histocompatibility complex tetramers containing Nef138-10(wt) or Nef138-10(2F) sequences. After in-vitro stimulation of PBMCs with cognate peptides, the CD8+ T-cell population was sorted into different fractions: positive only to the wild-type tetramer (wt-positive), positive only to the mutant tetramer (2F-positive), and positive to both wt-tetramers and mutant-tetramers (dual-positive). TCR repertoires of sorted epitope-specific CD8+ T-cell populations were determined by sequencing.
  
  
  RESULTS
  A 2F-positive population was rarely observed under our culture and staining conditions. The wt-positive CD8+ T-cell populations had a diverse TCR repertoire, but the TCR repertoires in dual-positive CD8+ populations were highly restricted. In the dual-positive CD8+ T-cell populations, most clonotypes used the TRBV4-1 and TRBJ2-7 gene segments for the TCR beta-chain and the TRAV8-3 and TRAJ40-1 for the TCR alpha-chain. The CDR3 region of the TCR beta-chain showed little variation.
  
  
  CONCLUSIONS
  These results provide an example of restricted TCR repertoire in a specific CTL response against the escaping epitope. We speculate that impairment of antigen presentation in escaping viruses may underlie the restricted repertoire.
authors.affiliation: Division of Infectious Diseases, Advanced Clinical Research Center, The University of Tokyo, Tokyo, Japan.
authors.forename: Eriko
authors.initials: E
authors.lastname: Miyazaki
authors.forename: Ai
authors.initials: A
authors.lastname: Kawana-Tachikawa
authors.forename: Mariko
authors.initials: M
authors.lastname: Tomizawa
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Nunoya
authors.forename: Takashi
authors.initials: T
authors.lastname: Odawara
authors.forename: Takeshi
authors.initials: T
authors.lastname: Fujii
authors.forename: Yi
authors.initials: Y
authors.lastname: Shi
authors.forename: George Fu
authors.initials: GF
authors.lastname: Gao
authors.forename: Aikichi
authors.initials: A
authors.lastname: Iwamoto
mesh_terms: D019943:Amino Acid Substitution / Q000276:immunology; D002478:Cells, Cultured; D003602:Cytotoxicity, Immunologic / Q000235:genetics / Q000276:immunology; D018984:Epitopes, T-Lymphocyte / Q000235:genetics / Q000276:immunology*; D015658:HIV Infections / Q000235:genetics / Q000276:immunology* / Q000821:virology; D015497:HIV-1 / Q000235:genetics / Q000276:immunology*; D015234:HLA-A Antigens / Q000276:immunology; D059871:HLA-A24 Antigen; D006801:Humans; D008213:Lymphocyte Activation / Q000276:immunology; D011948:Receptors, Antigen, T-Cell / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D054311:nef Gene Products, Human Immunodeficiency Virus / Q000235:genetics / Q000276:immunology
chemical_list: D018984:Epitopes, T-Lymphocyte; D015234:HLA-A Antigens; C438506:HLA-A*24:02 antigen; D059871:HLA-A24 Antigen; D011948:Receptors, Antigen, T-Cell; D054311:nef Gene Products, Human Immunodeficiency Virus; C514837:nef protein, Human immunodeficiency virus 1