Skip to main content

Volume 6 Supplement 3

AIDS Vaccine 2009

P17-28 LB. The antiviral efficacy of HIV-specific CD8+ T-cells to a conserved epitope is heavily dependent on the infecting HIV-1 isolate


The greatest challenge to developing an effective T-cell based vaccine against HIV-1 is its high genetic variability. We hypothesised that efficient CTL antiviral activity is not only dependent on conserved epitopes but is also heavily modulated by the infecting HIV strain, with virus specific polymorphisms altering the efficiency of antigen processing and presentation.


CTL Lysis Assays, ELISPOT assay, Live Virus ELISPOT (LVE), Viral Suppression Assay (VSA), Intracellular Antigen Processing Inhibition Assay (IAPIA) and Proteasomal Digestion Assay (PDA) were used.


We examined whether an invariant HLA-B8 restricted Nef90-97 epitope FL8 shared between five high titre viruses and eight recombinant vaccinia viruses expressing Nef from different viral isolates (clades A-H) could activate antiviral activity in FL8-specific cytotoxic T-lymphocytes (CTL). Surprisingly, despite epitope conservation, we found that CTL antiviral efficacy is heavily dependent on the infecting viral strain. Only a small proportion of HIV strains tested were correctly processed, whilst 77% were impaired or abolished. This occurred independently of clade-grouping and was associated with virus-specific polymorphisms in the epitope flanking region altering patterns of immunoproteasomal cleavage, to increase or inhibit epitope generation.


we demonstrate that CTL antiviral efficacy to this conserved immunodominant epitope is impaired in a strikingly high proportion of viral isolates. These findings have implications for evaluating the antiviral efficacy of dominant T-cell responses in patients and the effectiveness of vaccine-induced T-cells.

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

Ranasinghe, S., Kramer, H., Wright, C. et al. P17-28 LB. The antiviral efficacy of HIV-specific CD8+ T-cells to a conserved epitope is heavily dependent on the infecting HIV-1 isolate. Retrovirology 6 (Suppl 3), P410 (2009).

Download citation

  • Published:

  • DOI:


  • Antiviral Activity
  • Viral Isolate
  • Vaccinia
  • ELISPOT Assay
  • High Genetic Variability