Protective immunity and safety of a genetically modified influenza virus vaccine

PLoS One. 2014 Jun 13;9(6):e98685. doi: 10.1371/journal.pone.0098685. eCollection 2014.

Abstract

Recombinant influenza viruses are promising viral platforms to be used as antigen delivery vectors. To this aim, one of the most promising approaches consists of generating recombinant viruses harboring partially truncated neuraminidase (NA) segments. To date, all studies have pointed to safety and usefulness of this viral platform. However, some aspects of the inflammatory and immune responses triggered by those recombinant viruses and their safety to immunocompromised hosts remained to be elucidated. In the present study, we generated a recombinant influenza virus harboring a truncated NA segment (vNA-Δ) and evaluated the innate and inflammatory responses and the safety of this recombinant virus in wild type or knock-out (KO) mice with impaired innate (Myd88 -/-) or acquired (RAG -/-) immune responses. Infection using truncated neuraminidase influenza virus was harmless regarding lung and systemic inflammatory response in wild type mice and was highly attenuated in KO mice. We also demonstrated that vNA-Δ infection does not induce unbalanced cytokine production that strongly contributes to lung damage in infected mice. In addition, the recombinant influenza virus was able to trigger both local and systemic virus-specific humoral and CD8+ T cellular immune responses which protected immunized mice against the challenge with a lethal dose of homologous A/PR8/34 influenza virus. Taken together, our findings suggest and reinforce the safety of using NA deleted influenza viruses as antigen delivery vectors against human or veterinary pathogens.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Dogs
  • Gene Knockout Techniques
  • Homeodomain Proteins / genetics*
  • Immunity, Cellular / immunology
  • Influenza A virus / enzymology*
  • Influenza A virus / genetics
  • Influenza Vaccines / genetics*
  • Influenza Vaccines / immunology
  • Madin Darby Canine Kidney Cells
  • Mice
  • Mice, Inbred C57BL
  • Myeloid Differentiation Factor 88 / genetics*
  • Neuraminidase / genetics*
  • Neuraminidase / immunology
  • Orthomyxoviridae Infections / immunology*
  • Vaccines, Synthetic / genetics
  • Vaccines, Synthetic / immunology
  • Viral Proteins / genetics*
  • Viral Proteins / immunology

Substances

  • Homeodomain Proteins
  • Influenza Vaccines
  • Myd88 protein, mouse
  • Myeloid Differentiation Factor 88
  • Vaccines, Synthetic
  • Viral Proteins
  • RAG-1 protein
  • NA protein, influenza A virus
  • Neuraminidase

Grants and funding

This work was supported by grants from FIOCRUZ/PDTIS-Vacinas, and National Institute for Vaccine Development and Technology (CNPq/FAPEMIG N ° 015/2008), CNPq/MAPA/SDA N ° 064/2008, and Universal FAPEMIG. CNPq provided fellowships to RPAB, APCS, CCG, BHFL, GAOL, MAR, ACCP, DBO, MAA, CAZ, TMC, EAC, RCR, RTG and AMVM. CAPES provided fellowship to GMFA. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.