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Volume 6 Supplement 3

AIDS Vaccine 2009

P14-03. HIV-specific T-lymphocyte proliferative responses induced by a multigene multiclade HIV-1 DNA/MVA heterologous vaccine in Tanzanian volunteers

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Background

A phase I/II HIV vaccine trial (HIVIS 03) employing a multiclade, multigene HIV-1 DNA prime/MVA boost vaccine among healthy volunteers is ongoing in Dar es Salaam, Tanzania.

Methods

Sixty healthy HIV negative volunteers including 15 females, were randomised to 3 groups and were injected at months 0, 1 and 3 with plasmid DNA vaccine (produced by KI/SMI and Vecura, Sweden) containing gp160 of HIV-1 subtypes A, B, C; rev B; p17/p24 gag A, B and Rtmut B, at 1 mg i.d. (n = 20) or 3.8 mg i.m. (n = 20) or placebo (n = 20) using the Biojector. At month 9, a single i.m. injection with MVA 108 pfu of MVA/CMDR expressing HIV-1 genes env, gag, pol of CRF01A_E (produced by NIAID and WRAIR, USA) or placebo was administered. T-lymphocyte proliferative (TLP) responses to AT-2 inactivated HIV-1 antigen from virus isolates/clade MN/B, KNH1144/A, TZA125/C and CM235/A_E were tested by a standard 3H-thymidine uptake assay. TLP was reported as stimulation index (SI) and SI above 6 was considered positive based on mean reactivity at baseline in 40 volunteers.

Results

Two weeks after the 3rd DNA/placebo injection, 24 of 52 (46%) volunteers had positive TLP responses. Two weeks and two months after the HIV-MVA/placebo boost, 35 of 48 (73%) and 32 of 44 (73%) volunteers had positive TLP responses, respectively. Thus far, 33 volunteers have been tested six months after the HIV-MVA/placebo boost and 20 (61%) have positive TLP responses. There was a high degree of cross reactivity as shown by strong proliferative responses to all four isolates tested. The TLP responses were sustained and 6 months after the HIV-MVA boost the greatest reactivity was seen against CM235/A_E. The study remains blinded.

Conclusion

HIVIS03 DNA-MVA vaccine has so far demonstrated strong HIV-specific T-lymphocyte proliferative responses with a high degree of cross clade reactivity.

Author information

Correspondence to S Aboud.

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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 2.0 International License (https://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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Aboud, S., Mhalu, F., Bakari, M. et al. P14-03. HIV-specific T-lymphocyte proliferative responses induced by a multigene multiclade HIV-1 DNA/MVA heterologous vaccine in Tanzanian volunteers. Retrovirology 6, P191 (2009). https://doi.org/10.1186/1742-4690-6-S3-P191

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Keywords

  • Stimulation Index
  • Boost Vaccine
  • Strong Proliferative Response
  • Heterologous Vaccine
  • Negative Volunteer