Eriko Miyazaki, Ai Kawana-Tachikawa, Mariko Tomizawa, Jun-ichi Nunoya, Takashi Odawara, Takeshi Fujii, Yi Shi, George Fu Gao, Aikichi Iwamoto
Division of Infectious Diseases, Advanced Clinical Research Center, The University of Tokyo, Tokyo, Japan.
AIDS (London, England) 2009 Mar 27In 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. 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. 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. 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.
Eriko Miyazaki, Ai Kawana-Tachikawa, Mariko Tomizawa, Jun-ichi Nunoya, Takashi Odawara, Takeshi Fujii, Yi Shi, George Fu Gao, Aikichi Iwamoto. Highly restricted T-cell receptor repertoire in the CD8+ T-cell response against an HIV-1 epitope with a stereotypic amino acid substitution. AIDS (London, England). 2009 Mar 27;23(6):651-60
PMID: 19279440
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