Group M-based HIV-1 Gag peptides are frequently targeted by T cells in chronically infected US and Zambian patients.
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.
Bansal
Anju
A
Department of Medicine, Emory University, Atlanta, Georgia, USA.
Gough
Ethan
E
Ritter
Doug
D
Wilson
Craig
C
Mulenga
Joseph
J
Allen
Susan
S
Goepfert
Paul A
PA
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
D016915:AIDS Vaccines