Protection against multiple influenza A virus strains induced by candidate recombinant vaccine based on heterologous M2e peptides linked to flagellin

PLoS One. 2015 Mar 23;10(3):e0119520. doi: 10.1371/journal.pone.0119520. eCollection 2015.

Abstract

Matrix 2 protein ectodomain (M2e) is considered a promising candidate for a broadly protective influenza vaccine. M2e-based vaccines against human influenza A provide only partial protection against avian influenza viruses because of differences in the M2e sequences. In this work, we evaluated the possibility of obtaining equal protection and immune response by using recombinant protein on the basis of flagellin as a carrier of the M2e peptides of human and avian influenza A viruses. Recombinant protein was generated by the fusion of two tandem copies of consensus M2e sequence from human influenza A and two copies of M2e from avian A/H5N1 viruses to flagellin (Flg-2M2eh2M2ek). Intranasal immunisation of Balb/c mice with recombinant protein significantly elicited anti-M2e IgG in serum, IgG and sIgA in BAL. Antibodies induced by the fusion protein Flg-2M2eh2M2ek bound efficiently to synthetic peptides corresponding to the human consensus M2e sequence as well as to the M2e sequence of A/Chicken/Kurgan/05/05 RG (H5N1) and recognised native M2e epitopes exposed on the surface of the MDCK cells infected with A/PR/8/34 (H1N1) and A/Chicken/Kurgan/05/05 RG (H5N1) to an equal degree. Immunisation led to both anti-M2e IgG1 and IgG2a response with IgG1 prevalence. We observed a significant intracellular production of IL-4, but not IFN-γ, by CD4+ T-cells in spleen of mice following immunisation with Flg-2M2eh2M2ek. Immunisation with the Flg-2M2eh2M2ek fusion protein provided similar protection from lethal challenge with human influenza A viruses (H1N1, H3N2) and avian influenza virus (H5N1). Immunised mice experienced significantly less weight loss and decreased lung viral titres compared to control mice. The data obtained show the potential for the development of an M2e-flagellin candidate influenza vaccine with broad spectrum protection against influenza A viruses of various origins.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Viral / blood
  • Blotting, Western
  • Enzyme-Linked Immunosorbent Assay
  • Epitopes / immunology
  • Female
  • Filaggrin Proteins
  • Flagellin / immunology*
  • Humans
  • Immunization
  • Influenza A virus / immunology*
  • Influenza Vaccines / immunology*
  • Influenza, Human / immunology
  • Influenza, Human / prevention & control*
  • Influenza, Human / virology
  • Lung / immunology
  • Lung / virology
  • Mice
  • Mice, Inbred BALB C
  • Orthomyxoviridae Infections / immunology
  • Orthomyxoviridae Infections / prevention & control*
  • Orthomyxoviridae Infections / virology
  • Peptide Fragments / genetics
  • Peptide Fragments / immunology*
  • Recombinant Fusion Proteins / administration & dosage
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / immunology*
  • Viral Load
  • Viral Matrix Proteins / immunology*

Substances

  • Antibodies, Viral
  • Epitopes
  • FLG protein, human
  • Filaggrin Proteins
  • Influenza Vaccines
  • M2 protein, Influenza A virus
  • Peptide Fragments
  • Recombinant Fusion Proteins
  • Viral Matrix Proteins
  • Flagellin

Grants and funding

This work was supported by the Ministry of Education and Science of the Russian Federation (grant No 8292) and the fellowship of the President of Russia for young scientists awarded to R. Kotlyarov. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.