Protection against Multiple Influenza A Virus Strains Induced by Candidate Recombinant Vaccine Based on Heterologous M2e Peptides Linked to Flagellin

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.

A boosting skin vaccination with dissolving microneedle patch encapsulating M2e vaccine broadens the protective efficacy of conventional influenza vaccines

“…Different approaches have been used to improve the immunogenicity of M2e, including generating multimeric forms of M2e, supplemented delivery with other influenza vaccines, fusion with carrier proteins, incorporation into particles, and immunization together with potent adjuvants (13-15). Our work and many other studies have demonstrated that modified M2e-based vaccines greatly improved immune responses and strengthened protective functions against heterologous influenza virus infection (13, 16, 17). Thus, M2e antigen is a promising candidate for the development of universal influenza vaccines.…”

A novel linear neutralizing epitope of hepatitis E virus

“…Such phenomenon has been found in the influenza virus [48]. The L2 epitope is linear epitope, and the linear epitopes could be displayed and constructed according to methods which had been described and been extensively applied in numbers of investigations [31,34,[36][37][38]40,43,[49][50][51][52][53][54]. Although the immune response against immunodominant epitopes is effective in the prevention of HEV [25], epitope L2 is an alternative target for HEV vaccine development that may prevent future viral mutations with the extensive use of vaccines and the increasing anti-HEV immune pressure in the population.…”

Protein nanoparticle vaccine based on flagellin carrier fused to influenza conserved epitopes confers full protection against influenza A virus challenge

“…Tandem copies of M2e fused to TLR5 ligand flagellin were highly immunogenic in vivo , induced robust and long-lasting M2e-specific antibody responses and provided full protection against influenza A virus challenges (Huleatt et al, 2008; Mardanova et al, 2016; Stepanova et al, 2015; Wang et al, 2014a). In our study, the variable region of FliC was replaced with three types of weak antigens: four tandem copies of M2e, H1 HA2 domain and H3 HA2 domain (Fig 1).…”