title: Group M-based HIV-1 Gag peptides are frequently targeted by T cells in chronically infected US and Zambian patients.
abstract: BACKGROUND
  The enormous sequence diversity of HIV-1 has been a major obstacle in the development of a globally useful vaccine for AIDS. The consensus and ancestral sequence-based immunogens minimize the genetic distance between contemporary isolates and vaccine strains. Hence these sequences may be promising candidates for HIV vaccines or serve as a universal reagent set for evaluating Gag-specific responses.
  
  
  METHODS
  In this study, we measured the T-cell reactivity to consensus (subtype A, B, C and group M), ancestral (group M and subtype B) and HXB2 Gag peptides (15-mers overlapping by 11) in HIV-1-infected subjects from two reference populations. We evaluated the Gag-specific T-cell responses in 43 chronically infected US (subtype B) and 13 Zambian (subtype C) subjects using an interferon-gamma enzyme-linked immunosorbent spot assay.
  
  
  RESULTS
  Our findings demonstrate a broad cross-reactivity of nearly 70% among all the seven Gag immunogens evaluated. Consensus M sequences elicited similar levels of responses as did the consensus B, ancestral subtype B and HXB2 peptides in subtype B-infected US patients. In subtype C-infected Zambian subjects, responses of similar breadth and magnitude were elicited by consensus C, consensus M and ancestral M peptides.
  
  
  CONCLUSIONS
  Our data demonstrate that peptide pools based on consensus or ancestral M-based sequences can be used to evaluate Gag-specific responses elicited by subtype B or subtype C-based immunogens.
authors.affiliation: Department of Medicine, Emory University, Atlanta, Georgia, USA.
authors.forename: Anju
authors.initials: A
authors.lastname: Bansal
authors.forename: Ethan
authors.initials: E
authors.lastname: Gough
authors.forename: Doug
authors.initials: D
authors.lastname: Ritter
authors.forename: Craig
authors.initials: C
authors.lastname: Wilson
authors.forename: Joseph
authors.initials: J
authors.lastname: Mulenga
authors.forename: Susan
authors.initials: S
authors.lastname: Allen
authors.forename: Paul A
authors.initials: PA
authors.lastname: Goepfert
mesh_terms: D016915:AIDS Vaccines; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D015750:Genes, gag / Q000276:immunology*; D015658:HIV Infections / Q000276:immunology*; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D007111:Immunity, Cellular; D008297:Male; D013601:T-Lymphocytes / Q000276:immunology*; D014481:United States; D015024:Zambia
chemical_list: D016915:AIDS Vaccines