Persistent survival of prevalent clonotypes within an immunodominant HIV gag-specific CD8+ T cell response

J Immunol. 2011 Jan 1;186(1):359-71. doi: 10.4049/jimmunol.1001807. Epub 2010 Dec 6.

Abstract

CD8(+) T cells play a significant role in the control of HIV replication, yet the associated qualitative and quantitative factors that determine the outcome of infection remain obscure. In this study, we examined Ag-specific CD8(+) TCR repertoires longitudinally in a cohort of HLA-B*2705(+) long-term nonprogressors with chronic HIV-1 infection using a combination of molecular clonotype analysis and polychromatic flow cytometry. In each case, CD8(+) T cell populations specific for the immunodominant p24 Gag epitope KRWIILGLNK (KK10; residues 263-272) and naturally occurring variants thereof, restricted by HLA-B*2705, were studied at multiple time points; in addition, comparative data were collected for CD8(+) T cell populations specific for the CMV pp65 epitope NLVPMVATV (NV9; residues 495-503), restricted by HLA-A*0201. Dominant KK10-specific clonotypes persisted for several years and exhibited greater stability than their contemporaneous NV9-specific counterparts. Furthermore, these dominant KK10-specific clonotypes exhibited cross-reactivity with antigenic variants and expressed significantly higher levels of CD127 (IL-7Rα) and Bcl-2. Of note, we also found evidence that promiscuous TCR α-chain pairing associated with alterations in fine specificity for KK10 variants could contribute to TCR β-chain prevalence. Taken together, these data suggest that an antiapoptotic phenotype and the ability to cross-recognize variant epitopes contribute to clonotype longevity and selection within the peripheral memory T cell pool in the presence of persistent infection with a genetically unstable virus.

Publication types

  • Research Support, N.I.H., Intramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Antigen Presentation / immunology
  • Antigenic Variation / immunology
  • Apoptosis / immunology
  • CD8-Positive T-Lymphocytes / immunology*
  • CD8-Positive T-Lymphocytes / pathology
  • CD8-Positive T-Lymphocytes / virology*
  • Cell Separation
  • Cell Survival / immunology
  • Clone Cells
  • Epitopes, T-Lymphocyte / immunology*
  • Epitopes, T-Lymphocyte / metabolism
  • Flow Cytometry
  • HIV Infections / immunology
  • HIV Infections / pathology
  • HIV Infections / virology
  • HIV-1 / immunology*
  • Humans
  • Immune Evasion / immunology
  • Immunodominant Epitopes / immunology*
  • Molecular Sequence Data
  • Phenotype
  • Prevalence
  • gag Gene Products, Human Immunodeficiency Virus / immunology*

Substances

  • Epitopes, T-Lymphocyte
  • Immunodominant Epitopes
  • gag Gene Products, Human Immunodeficiency Virus