title: Recombinant M2e outer membrane vesicle vaccines protect against lethal influenza A challenge in BALB/c mice.
abstract: Currently approved influenza vaccines predominantly protect through antibodies directed against the highly variable glycoprotein hemagglutinin (HA), necessitating annual redesign and formulation based on epidemiological prediction of predominant circulating strains. More conserved influenza protein sequences, such as the ectodomain of the influenza M2 protein, or M2e, show promise as a component of a universal influenza A vaccine, but require a Th1-biased immune response for activity. Recently, recombinant, bacterially derived outer membrane vesicles (OMVs) demonstrated potential as a platform to promote a Th1-biased immune response to subunit antigens. Here, we engineer three M2e-OMV vaccines and show that all elicit strong IgG titers, with high IgG2a:IgG1 ratios, in BALB/c mice. Additionally, the administration of one M2e-OMV construct containing tandem heterologous M2e peptides (M2e4xHet-OMV) resulted in 100% survival against lethal doses of the mouse-adapted H1N1 influenza strain PR8. Passive transfer of antibodies from M2e4xHet-OMV vaccinated mice to unvaccinated mice also resulted in 100% survival to challenge, indicating that protection is driven largely via antibody-mediated immunity. The potential mechanism through which M2e-OMVs initiated the immune response was explored and it was found that the constructs triggered TLR1/2, TLR4, and TLR5. Our data indicate that OMVs have potential as a platform for influenza A vaccine development due to their unique adjuvant profile and intrinsic pathogen-mimetic nature.
authors.affiliation: Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14853, USA.
authors.forename: C Garrett
authors.initials: CG
authors.lastname: Rappazzo
authors.affiliation: Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Hannah C
authors.initials: HC
authors.lastname: Watkins
authors.affiliation: Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Cassandra M
authors.initials: CM
authors.lastname: Guarino
authors.affiliation: Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Annie
authors.initials: A
authors.lastname: Chau
authors.affiliation: Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Jody L
authors.initials: JL
authors.lastname: Lopez
authors.affiliation: School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Matthew P
authors.initials: MP
authors.lastname: DeLisa
authors.affiliation: Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Cynthia A
authors.initials: CA
authors.lastname: Leifer
authors.affiliation: Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Gary R
authors.initials: GR
authors.lastname: Whittaker
authors.affiliation: Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14853, USA; School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY 14853, USA. Electronic address: dap43@cornell.edu.
authors.forename: David
authors.initials: D
authors.lastname: Putnam
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D004926:Escherichia coli / Q000378:metabolism; D000067128:Extracellular Vesicles / Q000276:immunology*; D005260:Female; D007113:Immunity, Innate; D007074:Immunoglobulin G / Q000097:blood; D053118:Influenza A Virus, H1N1 Subtype; D007252:Influenza Vaccines / Q000276:immunology*; D008807:Mice, Inbred BALB C; D053758:Nanoparticles; D009976:Orthomyxoviridae Infections / Q000517:prevention & control*; D051193:Toll-Like Receptors / Q000819:agonists; D014614:Vaccines, Synthetic / Q000276:immunology; D014763:Viral Matrix Proteins / Q000276:immunology*; D000086082:Viroporin Proteins
chemical_list: D000914:Antibodies, Viral; D007074:Immunoglobulin G; D007252:Influenza Vaccines; D051193:Toll-Like Receptors; D014614:Vaccines, Synthetic; D014763:Viral Matrix Proteins; C488937:M2 protein, Influenza A virus; D000086082:Viroporin Proteins
keywords: M2e subunit vaccines; Outer membrane vesicles; TLR agonists; Universal influenza vaccine