Fusion to Flaviviral Leader Peptide Targets HIV-1 Reverse Transcriptase for Secretion and Reduces Its Enzymatic Activity and Ability to Induce Oxidative Stress but Has No Major Effects on Its Immunogenic Performance in DNA-Immunized Mice

J Immunol Res. 2017:2017:7407136. doi: 10.1155/2017/7407136. Epub 2017 Jun 22.

Abstract

Reverse transcriptase (RT) is a key enzyme in viral replication and susceptibility to ART and a crucial target of immunotherapy against drug-resistant HIV-1. RT induces oxidative stress which undermines the attempts to make it immunogenic. We hypothesized that artificial secretion may reduce the stress and make RT more immunogenic. Inactivated multidrug-resistant RT (RT1.14opt-in) was N-terminally fused to the signal providing secretion of NS1 protein of TBEV (Ld) generating optimized inactivated Ld-carrying enzyme RT1.14oil. Promotion of secretion prohibited proteasomal degradation increasing the half-life and content of RT1.14oil in cells and cell culture medium, drastically reduced the residual polymerase activity, and downmodulated oxidative stress. BALB/c mice were DNA-immunized with RT1.14opt-in or parental RT1.14oil by intradermal injections with electroporation. Fluorospot and ELISA tests revealed that RT1.14opt-in and RT1.14oil induced IFN-γ/IL-2, RT1.14opt-in induced granzyme B, and RT1.14oil induced perforin production. Perforin secretion correlated with coproduction of IFN-γ and IL-2 (R = 0,97). Both DNA immunogens induced strong anti-RT antibody response. Ld peptide was not immunogenic. Thus, Ld-driven secretion inferred little change to RT performance in DNA immunization. Positive outcome was the abrogation of polymerase activity increasing safety of RT-based DNA vaccines. Identification of the molecular determinants of low cellular immunogenicity of RT requires further studies.

MeSH terms

  • AIDS Vaccines / immunology*
  • Animals
  • Cell Line
  • Female
  • Granzymes / genetics
  • HIV Antibodies / blood
  • HIV Reverse Transcriptase / genetics
  • HIV Reverse Transcriptase / immunology*
  • HIV Reverse Transcriptase / metabolism*
  • HIV-1 / enzymology
  • HIV-1 / immunology
  • Humans
  • Immunogenicity, Vaccine*
  • Interferon-gamma
  • Interleukin-2
  • Mice
  • Mice, Inbred BALB C
  • Oxidative Stress*
  • Protein Sorting Signals / genetics*
  • Recombinant Fusion Proteins / immunology
  • Recombinant Fusion Proteins / metabolism
  • Vaccines, DNA / administration & dosage
  • Vaccines, DNA / adverse effects
  • Vaccines, DNA / immunology*

Substances

  • AIDS Vaccines
  • HIV Antibodies
  • Interleukin-2
  • Protein Sorting Signals
  • Recombinant Fusion Proteins
  • Vaccines, DNA
  • Interferon-gamma
  • reverse transcriptase, Human immunodeficiency virus 1
  • HIV Reverse Transcriptase
  • Granzymes