Skip to main content

Volume 6 Supplement 3

AIDS Vaccine 2009

  • Poster presentation
  • Open access
  • Published:

P16-03. Persistence of robust cross-reactive group M consensus T-cell responses in a chronic HIV-1 clade A1 and D-infected Ugandan population


HIV-1 group-M exhibits extraordinary genetic variation, cross-reactivity of immunogens based on consensus clades could be continuously diminishing as the AIDS epidemic progresses. Characterisation of cross-reactive T-cell responses to more central group M consensus peptides in this multi-clade population has not been performed; and could be pertinent for global vaccine


Fifty, randomly selected, HIV-1 chronically infected, ART-naïve, Ugandan adults with CD4 ≥ 350 cells/μl were screened for consensus group-M Gag and Nef-induced IFN-γ using ELISpot. Gag sequence diversity was evaluated and correlated with IFN-γ.


Clades A1, D, and inter-subtype recombinants A1/C, A1/D occurred at frequencies 44%, 51%, 2.4% and 2.4%, (n = 41), respectively. Infecting gag sequences highly diverged from consensus group-M (median 9.2: interquartile range (IQR) 8.6–10%), and reveled evidence of immunological pressure. Inter-clade divergence was above the 3% threshold in clades A1 (5.3: 4.8–5.8%) and D (6.1: 5.8–6.9%). High avidity Gag (96: 19–267 ng/ml) and Nef-induced IFN-γ responses (74: 12–159 ng/ml) were detected. All gag regions were recognized, highest magnitudes were to p24. Gag was more targeted than Nef (44/50[88%] vs. 32/50[64%]; p = 0.014, Fisher's Exact); and induced higher IFN-γ magnitude (2420, 625–6445 vs. 475: 0–2000 SFU/106 PBMCs; p = 0.0003) and breadth (2: 1–3 vs. 1: 0–1 epitopes; p = 0.0001, Mann-Whitney), respectively, with no detectable difference between clades. Nef-induced IFN-γ responses targeted the conserved core region, and depicted lower magnitude (0: 0–765 vs. 1090: 275–2310 SFU/106 PBMCs; p = 0.04) and breadth in clade A1 than D (0: 0–1 vs. 1: 1–2 epitopes; p = 0.03), respectively.


Robust, cross-reactive, HIV-1 consensus group-M cellular responses in this highly diverse virus population implies a potential for a vaccine using immunogens based on these sequences despite the increasing diversity over time. Nef responses correlated with clade D known to be linked with faster disease progression; data suggests particular focus on Gag previously also shown to correlate with protection in this population.

Author information

Authors and Affiliations


Rights and permissions

Open Access This article is published under license to BioMed Central Ltd. This is an Open Access article is distributed under the terms of the Creative Commons Attribution License ( ), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Reprints and permissions

About this article

Cite this article

Serwanga, J., Mugaba, S., Pimego, E. et al. P16-03. Persistence of robust cross-reactive group M consensus T-cell responses in a chronic HIV-1 clade A1 and D-infected Ugandan population. Retrovirology 6 (Suppl 3), P232 (2009).

Download citation

  • Published:

  • DOI: