Lower levels of gamma interferon expressed by a pseudotyped single-cycle simian immunodeficiency virus enhance immunogenicity in rats

Yue Peng, Fan Ching Lin, Paulo H. Verardi, Leslie A. Jones, Tilahun Yilma

Research output: Contribution to journalArticle

2 Scopus citations

Abstract

A vaccine for human immunodeficiency virus (HIV) infection is desperately needed to control the AIDS pandemic. To address this problem, we constructed single-cycle simian immunodeficiency viruses (SIVs) pseudotyped with the glycoprotein of vesicular stomatitis virus and expressing different levels of gamma interferon (IFN-γ) as a potential vaccine strategy. We previously showed that IFN-γ expression by pseudotyped SIVs does not alter viral single-cycle infectivity. T cells primed with dendritic cells transduced by pseudotyped SIVs expressing high levels of IFN-γ had stronger T-cell responses than those primed with dendritic cells transduced by constructs lacking IFN-γ. In the present study, we tested the immunogenicities of these pseudotyped SIVs in a rat model. The construct expressing low levels of rat IFN-γ (dSIVLRγ) induced higher levels of cell-mediated and humoral immune responses than the construct lacking IFN-γ (dSIVR). Rats vaccinated with dSIVLRγ also had lower viral loads than those vaccinated with dSIVR when inoculated with a recombinant vaccinia virus expressing SIV Gag-Pol as a surrogate challenge. The construct expressing high levels of IFN-γ (dSIVHRγ) did not further enhance immunity and was less protective than dSIVLRγ. In conclusion, the data indicated that IFN-γ functioned as an adjuvant to augment antigen-specific immune responses in a dose- and cell type-related manner in vivo. Thus, fine-tuning of the cytokine expression appears to be essential in designing vaccine vectors expressing adjuvant genes such as the gene for IFN-γ. Furthermore, we provide evidence of the utility of the rat model to evaluate the immunogenicities of single-cycle HIV/SIV recombinant vaccines before initiating studies with nonhuman primate models.

Original languageEnglish (US)
Pages (from-to)1592-1601
Number of pages10
JournalJournal of Virology
Volume83
Issue number4
DOIs
StatePublished - Feb 2009

ASJC Scopus subject areas

  • Immunology
  • Virology

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