Codon optimization and improved delivery/immunization regimen enhance the immune response against wild-type and drug-resistant HIV-1 reverse transcriptase, preserving its Th2-polarity

Sci Rep. 2018 May 24;8(1):8078. doi: 10.1038/s41598-018-26281-z.

Abstract

DNA vaccines require a considerable enhancement of immunogenicity. Here, we optimized a prototype DNA vaccine against drug-resistant HIV-1 based on a weak Th2-immunogen, HIV-1 reverse transcriptase (RT). We designed expression-optimized genes encoding inactivated wild-type and drug-resistant RTs (RT-DNAs) and introduced them into mice by intradermal injections followed by electroporation. RT-DNAs were administered as single or double primes with or without cyclic-di-GMP, or as a prime followed by boost with RT-DNA mixed with a luciferase-encoding plasmid ("surrogate challenge"). Repeated primes improved cellular responses and broadened epitope specificity. Addition of cyclic-di-GMP induced a transient increase in IFN-γ production. The strongest anti-RT immune response was achieved in a prime-boost protocol with electroporation by short 100V pulses done using penetrating electrodes. The RT-specific response, dominated by CD4+ T-cells, targeted epitopes at aa 199-220 and aa 528-543. Drug-resistance mutations disrupted the epitope at aa 205-220, while the CTL epitope at aa 202-210 was not affected. Overall, multiparametric optimization of RT strengthened its Th2- performance. A rapid loss of RT/luciferase-expressing cells in the surrogate challenge experiment revealed a lytic potential of anti-RT response. Such lytic CD4+ response would be beneficial for an HIV vaccine due to its comparative insensitivity to immune escape.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • AIDS Vaccines* / administration & dosage
  • AIDS Vaccines* / genetics
  • Animals
  • Calibration
  • Cells, Cultured
  • Codon
  • Drug Delivery Systems
  • Drug Resistance, Viral* / genetics
  • Drug Resistance, Viral* / immunology
  • Epitopes / genetics
  • Epitopes / immunology
  • HIV Infections / immunology
  • HIV Infections / therapy*
  • HIV Reverse Transcriptase / genetics
  • HIV Reverse Transcriptase / immunology*
  • HIV-1 / genetics
  • HIV-1 / immunology
  • HeLa Cells
  • Humans
  • Immune Evasion / genetics
  • Immune Evasion / immunology
  • Immunization, Secondary / methods
  • Immunization, Secondary / standards
  • Immunogenicity, Vaccine / genetics
  • Mice
  • Mice, Inbred BALB C
  • Quality Improvement
  • Th2 Cells / immunology*
  • Th2 Cells / metabolism
  • Vaccination / methods*
  • Vaccination / standards
  • Vaccines, DNA* / administration & dosage
  • Vaccines, DNA* / genetics

Substances

  • AIDS Vaccines
  • Codon
  • Epitopes
  • Vaccines, DNA
  • reverse transcriptase, Human immunodeficiency virus 1
  • HIV Reverse Transcriptase