Skip to main content

Volume 6 Supplement 3

AIDS Vaccine 2009

OA07-04 LB. Immunogenicity of ALVAC-HIV® (vCP1521) and AIDSVAX® B/E prime boose vaccination in RV144, the Thai Phase III HIV vaccine trial

Background

The Phase III trial of ALVAC-HIV® and AIDSVAX® B/E in Thailand began in October 2003 and concluded in June 2009. Both vaccine candidates express HIV-1 circulating recombinant form (CRF) 01_AE and subtype B antigens. This study assessed whether the Phase III vaccine lots show immunogenicity comparable to the previous Phase I/II study of the identical immunization regimen.

Methods

A list of blinded samples from persons completing all 4 injections with either placebo or vaccine and remained HIV negative at the end of the trial was provided. Peripheral blood mononuclear cells (PBMC) or plasma were tested to CRF 01_AE and subtype B vaccine antigens in the following validated assays: (1) Interferon-gamma (IFN-γ) ELISpot; (2) IFN-γ/interleukin-2 intracellular cytokine staining (ICS); (3) Binding antibody (BAb). ELISpot and ICS assays measured responses to Env (92TH023) and Gag (LAI) peptide pools prior to and 6 months following the completion of immunization. BAb was measured using reciprocal dilution EIA to A244 and MN gp120 and BH10 p24 prior to and at 2 weeks following the completion of immunization.

Results

Data will be un-blinded to treatment assignment by October 2009. Analyses of post-injection responses to Env and Gag by ELISpot revealed an overall frequency of 14%, with Env responses (11%) predominating over Gag (5%). The overall frequency of ICS responses to HIV peptides in samples studied to date was 35% and was greater for CD4 (26%) than CD8 (9%) T cells, with responses to Env again predominating: 26% versus 1% Gag for CD4 and 6% Env versus 2% Gag for CD8 T cells. The frequency of BAb responses to p24 was 37% and was identical for CRF01_AE and MN gp120 (70%).

Conclusion

Cellular and humoral immune responses to the ALVAC-HIV® + AIDSVAX® B/E regimen were predominantly to HIV Env and appear similar to those seen in the earlier Phase I/II study.

Author information

Affiliations

Authors

Corresponding author

Correspondence to MS de Souza.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

de Souza, M., Trichavaroj, R., Schuetz, A. et al. OA07-04 LB. Immunogenicity of ALVAC-HIV® (vCP1521) and AIDSVAX® B/E prime boose vaccination in RV144, the Thai Phase III HIV vaccine trial. Retrovirology 6, O52 (2009). https://doi.org/10.1186/1742-4690-6-S3-O52

Download citation

Keywords

  • Humoral Immune Response
  • Vaccine Candidate
  • Vaccine Trial
  • Recombinant Form
  • Vaccine Antigen