Consensus HIV-1 FSU-A integrase gene variants electroporated into mice induce polyfunctional antigen-specific CD4+ and CD8+ T cells

PLoS One. 2013 May 8;8(5):e62720. doi: 10.1371/journal.pone.0062720. Print 2013.

Abstract

Our objective is to create gene immunogens targeted against drug-resistant HIV-1, focusing on HIV-1 enzymes as critical components in viral replication and drug resistance. Consensus-based gene vaccines are specifically fit for variable pathogens such as HIV-1 and have many advantages over viral genes and their expression-optimized variants. With this in mind, we designed the consensus integrase (IN) of the HIV-1 clade A strain predominant in the territory of the former Soviet Union and its inactivated derivative with and without mutations conferring resistance to elvitegravir. Humanized IN gene was synthesized; and inactivated derivatives (with 64D in the active site mutated to V) with and without elvitegravir-resistance mutations were generated by site-mutagenesis. Activity tests of IN variants expressed in E coli showed the consensus IN to be active, while both D64V-variants were devoid of specific activities. IN genes cloned in the DNA-immunization vector pVax1 (pVaxIN plasmids) were highly expressed in human and murine cell lines (>0.7 ng/cell). Injection of BALB/c mice with pVaxIN plasmids followed by electroporation generated potent IFN-γ and IL-2 responses registered in PBMC by day 15 and in splenocytes by day 23 after immunization. Multiparametric FACS demonstrated that CD8+ and CD4+ T cells of gene-immunized mice stimulated with IN-derived peptides secreted IFN-γ, IL-2, and TNF-α. The multi-cytokine responses of CD8+ and CD4+ T-cells correlated with the loss of in vivo activity of the luciferase reporter gene co-delivered with pVaxIN plasmids. This indicated the capacity of IN-specific CD4+ and CD8+ T-cells to clear IN/reporter co-expressing cells from the injection sites. Thus, the synthetic HIV-1 clade A integrase genes acted as potent immunogens generating polyfunctional Th1-type CD4+ and CD8+ T cells. Generation of such response is highly desirable for an effective HIV-1 vaccine as it offers a possibility to attack virus-infected cells via both MHC class I and II pathways.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • CD4-Positive T-Lymphocytes / immunology*
  • CD8-Positive T-Lymphocytes / immunology*
  • Cell Line
  • Drug Resistance, Viral / genetics*
  • Drug Resistance, Viral / immunology
  • Electroporation
  • Escherichia coli
  • Flow Cytometry
  • HIV Integrase / biosynthesis
  • HIV Integrase / genetics*
  • HIV Integrase Inhibitors / metabolism*
  • HIV-1 / enzymology*
  • HIV-1 / immunology
  • Humans
  • Luciferases
  • Lymphocyte Activation / immunology*
  • Mice
  • Mice, Inbred BALB C
  • Mutagenesis, Site-Directed
  • Quinolones

Substances

  • HIV Integrase Inhibitors
  • Quinolones
  • elvitegravir
  • Luciferases
  • HIV Integrase

Grants and funding

Financial support in the form of Swedish Research Council grant K2011-79X-21744-01-6 (www.vr.se); the New Visby program of the Swedish Institute (http://www.studyinsweden.se/Scholarships/SI-scholarships/Visby-Program/); Russian Foundation for Basic Research (http://www.rfbr.ru/rffi/ru/) grant 11-04-01569-a; Russian Federal Agency for Science and Innovation (http://www.fasi.gov.ru/), grant 02.512.11.2291; and a grant from the President of the Russian Federation for young PhDs (http://grants.extech.ru/z_otch2004.php?mlevel=100/) MK-5287.2011.4 are gratefully acknowledged. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.