DNA prime/MVTT boost regimen with HIV-1 mosaic Gag enhances the potency of antigen-specific immune responses.

Tue, 07/24/2018 - 9:00am -- dana
TitleDNA prime/MVTT boost regimen with HIV-1 mosaic Gag enhances the potency of antigen-specific immune responses.
Publication TypeJournal Article
Year of Publication2018
AuthorsLiu W, Wong YChun, M Y Chen S, Tang J, Wang H, Cheung AKa Loon, Chen Z
Date Published2018 07 25

HIV-1 diversity and latent reservoir are the major challenges for the development of an effective AIDS vaccine. It is well indicated that Gag-specific CD8 T cells serve as the dominant host immune surveillance for HIV-1 control, but it still remains a challenge for vaccine design to induce broader and stronger cytotoxic T cell immunity against the virus. Genetic variation of the HIV-1 gag gene across different clades is one of the reasons for the reduction of antigenic epitope coverage. Here, we report an immunization strategy with heterologous vaccines expressing a mosaic Gag antigen aimed to increase antigenic breadth against a wider spectrum of HIV-1 strains. Priming using a DNA vaccine via in vivo electroporation, followed by boosting with a live replication-competent modified vaccinia TianTan (MVTT) vectored vaccine, elicited greater and broader protective Gag-specific immune responses in mice. Compared to DNA or MVTT homologous immunization, the heterologous DNA/MVTT vaccination resulted in higher frequencies of broadly reactive, Gag-specific, polyfunctional, long-lived cytotoxic CD8 T cells, as well as increased anti-Gag antibody titer. Importantly, the DNA/MVTT heterologous vaccination induced protection against EcoHIV and mesothelioma AB1-Gag challenges. In summary, the stronger protective Gag-specific immunity induced by the heterologous regimen using two safe vectors shows promise for further development to enhance anti-HIV-1 immunity. Our study has important implications for immunogen design and the development of an effective HIV-1 heterologous vaccination strategy.

Alternate JournalVaccine
PubMed ID29961605