title: Control of HIV-1 replication in vitro by vaccine-induced human CD8(+) T cells through conserved subdominant Pol epitopes.
abstract: OBJECTIVE
  The specificity of CD8(+) T cells is critical for early control of founder/transmitted and reactivated HIV-1. To tackle HIV-1 variability and escape, we designed vaccine immunogen HIVconsv assembled from 14 highly conserved regions of mainly Gag and Pol proteins. When administered to HIV-1-negative human volunteers in trial HIV-CORE 002, HIVconsv vaccines elicited CD8(+) effector T cells which inhibited replication of up to 8 HIV-1 isolates in autologous CD4(+) cells. This inhibition correlated with interferon-γ production in response to Gag and Pol peptide pools, but direct evidence of the inhibitory specificity was missing. Here, we aimed to define through recognition of which epitopes these effectors inhibit HIV-1 replication.
  
  
  METHODS
  CD8(+) T-cells from the 3 broadest HIV-1 inhibitors out of 23 vaccine recipients were expanded in culture by Gag or Pol peptide restimulation and tested in viral inhibition assay (VIA) using HIV-1 clade B and A isolates.
  
  
  METHODS
  Frozen PBMCs were expanded first using peptide pools from Gag or Pol conserved regions and tested on HIV-1-infected cells in VIA or by individual peptides for their effector functions. Single peptide specificities responsible for inhibition of HIV-1 replication were then confirmed by single-peptide expanded effectors tested on HIV-1-infected cells.
  
  
  RESULTS
  We formally demonstrated that the vaccine-elicited inhibitory human CD8(+) T cells recognized conserved epitopes of both Pol and Gag proteins. We defined 7 minimum epitopes, of which 3 were novel, presumably naturally subdominant. The effectors were oligofunctional producing several cytokines and chemokines and killing peptide-pulsed target cells.
  
  
  CONCLUSIONS
  These results implicate the use of functionally conserved regions of Pol in addition to the widely used Gag for T-cell vaccine design. Proportion of volunteers developing these effectors and their frequency in circulating PBMC are separate issues, which can be addressed, if needed, by more efficient vector and regimen delivery of conserved immunogens.
authors.affiliation: The Jenner Institute, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7DQ, United Kingdom.
authors.forename: Tina
authors.initials: T
authors.lastname: Ahmed
authors.affiliation: The Jenner Institute, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7DQ, United Kingdom.
authors.forename: Nicola J
authors.initials: NJ
authors.lastname: Borthwick
authors.affiliation: Human Immunology Laboratory, International AIDS Vaccine Initiative, London SW10 9NH, United Kingdom; Faculty of Medicine, Imperial College, London SW7 2AZ, United Kingdom.
authors.forename: Jill
authors.initials: J
authors.lastname: Gilmour
authors.affiliation: Human Immunology Laboratory, International AIDS Vaccine Initiative, London SW10 9NH, United Kingdom.
authors.forename: Peter
authors.initials: P
authors.lastname: Hayes
authors.affiliation: Human Immunology Laboratory, International AIDS Vaccine Initiative, London SW10 9NH, United Kingdom; Nuffield Department of Medicine, NDM Research Building, University of Oxford, Oxford OX3 7FZ, United Kingdom; Oxford NIHR Biomedical Research Centre, University of Oxford, Oxford, United Kingdom.
authors.forename: Lucy
authors.initials: L
authors.lastname: Dorrell
authors.affiliation: The Jenner Institute, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7DQ, United Kingdom; International Research Center for Medical Sciences, Kumamoto University, 2-2-1 Honjo, Chuo-ku, Japan. Electronic address: tomas.hanke@ndm.ox.ac.uk.
authors.forename: Tomáš
authors.initials: T
authors.lastname: Hanke
mesh_terms: D016915:AIDS Vaccines / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D018604:Epitope Mapping; D018984:Epitopes, T-Lymphocyte / Q000276:immunology*; D016655:HIV Core Protein p24 / Q000276:immunology; D015658:HIV Infections / Q000517:prevention & control; D015497:HIV-1 / Q000502:physiology*; D006801:Humans; D014779:Virus Replication; D054302:pol Gene Products, Human Immunodeficiency Virus / Q000276:immunology*
chemical_list: D016915:AIDS Vaccines; D018984:Epitopes, T-Lymphocyte; D016655:HIV Core Protein p24; C514799:p24 protein, Human Immunodeficiency Virus Type 1; D054302:pol Gene Products, Human Immunodeficiency Virus
keywords: Conserved region vaccine; HIV-1 vaccines; Human CD8(+) T cells; T cell epitopes; T cell vaccines; Virus inhibition assay (VIA)