Cohort-Specific Peptide Reagents Broaden Depth and Breadth Estimates of the CD8 T Cell Response to HIV-1 Gag Potential T Cell Epitopes

An effective HIV vaccine will need to stimulate immune responses against the sequence diversity presented in circulating virus strains. In this study, we evaluate breadth and depth estimates of potential T-cell epitopes (PTEs) in transmitted founder virus sequence-derived cohort-specific peptide reagents against reagents representative of consensus and global sequences. CD8 T-cells from twenty-six HIV-1+ PBMC donor samples, obtained at 1-year post estimated date of infection, were evaluated. ELISpot assays compared responses to 15mer consensus (n = 121), multivalent-global (n = 320), and 10mer multivalent cohort-specific (n = 300) PTE peptides, all mapping to the Gag antigen. Responses to 38 consensus, 71 global, and 62 cohort-specific PTEs were confirmed, with sixty percent of common global and cohort-specific PTEs corresponding to consensus sequences. Both global and cohort-specific peptides exhibited broader epitope coverage compared to commonly used consensus reagents, with mean breadth estimates of 3.2 (global), 3.4 (cohort) and 2.2 (consensus) epitopes. Global or cohort peptides each identified unique epitope responses that would not be detected if these peptide pools were used alone. A peptide set designed around specific virologic and immunogenetic characteristics of a target cohort can expand the detection of CD8 T-cell responses to epitopes in circulating viruses, providing a novel way to better define the host response to HIV-1 with implications for vaccine development

Home-based voluntary HIV counselling and testing found highly acceptable and to reduce inequalities

<p>Abstract</p> <p>Background</p> <p>Low uptake of voluntary HIV counselling and testing (VCT) in sub-Saharan Africa is raising acceptability concerns which might be associated with ways by which it is offered. We investigated the acceptability of home-based delivery of counselling and HIV testing in urban and rural populations in Zambia where VCT has been offered mostly from local clinics.</p> <p>Methods</p> <p>A population-based HIV survey was conducted in selected communities in 2003 (n = 5035). All participants stating willingness to be HIV tested were offered VCT at home and all counselling was conducted in the participants' homes. In the urban area post-test counselling and giving of results were done the following day whereas in rural areas this could take 1-3 weeks.</p> <p>Results</p> <p>Of those who indicated willingness to be HIV tested, 76.1% (95%CI 74.9-77.2) were counselled and received the test result. Overall, there was an increase in the proportion ever HIV tested from 18% before provision of home-based VCT to 38% after. The highest increase was in rural areas; among young rural men aged 15-24 years up from 14% to 42% vs. for urban men from 17% to 37%. Test rates by educational attainment changed from being positively associated to be evenly distributed after home-based VCT.</p> <p>Conclusions</p> <p>A high uptake was achieved by delivering HIV counselling and testing at home. The highest uptakes were seen in rural areas, in young people and groups with low educational attainment, resulting in substantial reductions in existing inequalities in accessing VCT services.</p

Lost opportunities in HIV prevention: programmes miss places where exposures are highest

Background: Efforts at HIV prevention that focus on high risk places might be more effective and less stigmatizing than those targeting high risk groups. The objective of the present study was to assess risk behaviour patterns, signs of current preventive interventions and apparent gaps in places where the risk of HIV transmission is high and in communities with high HIV prevalence. Methods: The PLACE method was used to collect data. Inhabitants of selected communities in Lusaka and Livingstone were interviewed about where people met new sexual partners. Signs of HIV preventive activities in these places were recorded. At selected venues, people were interviewed about their sexual behaviour. Peer educators and staff of NGOs were also interviewed. Results: The places identified were mostly bars, restaurants or sherbeens, and fewer than 20% reported any HIV preventive activity such as meetings, pamphlets or posters. In 43% of places in Livingstone and 26% in Lusaka, condoms were never available. There were few active peer educators. Among the 432 persons in Lusaka and 676 in Livingstone who were invited for interview about sexual behaviour, consistent condom use was relatively high in Lusaka (77%) but low in Livingstone (44% of men and 34% of women). Having no condom available was the most common reason for not using one. Condom use in Livingstone was higher among individuals socializing in places where condoms always were available. Conclusion: In the places studied we found a high prevalence of behaviours with a high potential for HIV transmission but few signs of HIV preventive interventions. Covering the gaps in prevention in these high exposure places should be given the highest priority