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Volume 6 Supplement 3

AIDS Vaccine 2009

OA04-02. Strong HIV-specific CD4 and CD8 T-lymphocyte proliferation in HIV-1 DNA prime/modified vaccinia virus Ankara (MVA) heterologous boost vaccinees

Background

We determined HIV-1-vaccine-induced lymphoproliferative responses in vaccinees immunized with a multigene, multiclade HIV-1 plasmid DNA vaccine boosted with heterologous HIV-1 recombinant MVA in a phase I HIV safety and immunogenicity study (HIVIS01/02).

Methods

Healthy volunteers were immunized intradermally or intramuscularly (with or without adjuvant GM-CSF protein) with DNA expressing HIV-1 gag, env, rev and rt at months 0, 1 and 3 using a Biojector and were boosted at nine months with an MVA expressing heterologous inserts of HIV-1 gag, env and pol genes. Lymphoproliferative responses to AT-2 inactivated HIV-1 antigen were tested by a 3H-thymidine uptake assay and a flow-cytometric assay of specific cell-mediated immune-response in activated whole blood (FASCIA-WB) two weeks after HIV-1 MVA boost (n = 38). A FASCIA using peripheral blood mononuclear cells (FASCIA-PBMC) was also employed during the later part of the study (n = 14).

Results

Thirty-five of 38 (92%) vaccinees were reactive by the 3H-thymidine-uptake assay (SI > 8). Thirty-two of 38 (84%) vaccinees were reactive by the CD3+CD4+ T-cell FASCIA-WB (% stimulation > 1.2), seven (18%) also exhibited CD8+ (CD3+ CD4-) T-cell responses. Of the 14 vaccinees analyzed using all three assays, ten (71%) and eleven (79%) demonstrated CD4+ T-cell responses in FASCIA-WB and FASCIA-PBMC, respectively. CD8+ T-cell reactivity was observed in 3 of 14 (21%) and 7 of 14 (50%) using the FASCIA-WB and FASCIA-PBMC, respectively. There was strong correlation between the proliferative responses measured by the 3H-thymidine uptake assay and the CD4+ T-cell FASCIA-WB (r = 0.68; p < 0.01).

Conclusion

HIV-1 specific T-lymphocyte proliferative responses were detected in a high proportion (37/38) of volunteers following HIV-1 DNA/MVA immunization. The FASCIA revealed both CD4+ and CD8+ T-cell proliferation in response to HIV-1 antigen stimulation. A standardized FASCIA-PBMC, which allows simultaneous phenotyping may be an option to the conventional 3H-thymidine uptake assay for assessment of vaccine-induced T-cell proliferation, especially in isotope-restricted settings.

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Correspondence to C Nilsson.

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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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Nilsson, C., Aboud, S., Karlén, K. et al. OA04-02. Strong HIV-specific CD4 and CD8 T-lymphocyte proliferation in HIV-1 DNA prime/modified vaccinia virus Ankara (MVA) heterologous boost vaccinees. Retrovirology 6, O26 (2009). https://doi.org/10.1186/1742-4690-6-S3-O26

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Keywords

  • Vaccinia
  • Lymphoproliferative Response
  • Boost Vaccinee
  • Heterologous Boost
  • Simultaneous Phenotyping