title: An influenza A vaccine based on tetrameric ectodomain of matrix protein 2.
abstract: Matrix protein 2 (M2) of influenza A is a tetrameric type III membrane protein that functions as a proton-selective channel. The extracellular domain (M2e) has remained nearly invariable since the first human influenza strain was isolated in 1933. By linking a modified form of the leucine zipper of the yeast transcription factor GCN4 to M2e, we obtained a recombinant tetrameric protein, M2e-tGCN4. This protein mimics the quaternary structure of the ectodomain of the natural M2 protein. M2e-tGCN4 was purified, biochemically characterized, and used to immunize BALB/c mice. High M2e-specific serum IgG antibody titers were obtained following either intraperitoneal or intranasal administration. Immunized mice were protected fully against a potentially lethal influenza A virus challenge. Antibodies raised by M2e-tGCN4 immunization specifically bound to the surface of influenza-infected cells and to an M2-expressing cell line. Using a M2e peptide competition enzyme-linked immunosorbent assay with M2-expressing cells as target, we obtained evidence that M2e-tGCN4 induces antibodies that are specific for the native tetrameric M2 ectodomain. Therefore, fusion of an oligomerization domain to the extracellular part of a transmembrane protein allows it to mimic the natural quaternary structure and can promote the induction of oligomer-specific antibodies.
authors.affiliation: Department of Molecular Biomedical Research, Vlaams Instituut voor Biotechnologie (VIB), B9052 Ghent, Belgium.
authors.forename: Marina
authors.initials: M
authors.lastname: De Filette
authors.forename: Wouter
authors.initials: W
authors.lastname: Martens
authors.forename: Kenny
authors.initials: K
authors.lastname: Roose
authors.forename: Tom
authors.initials: T
authors.lastname: Deroo
authors.forename: Frederik
authors.initials: F
authors.lastname: Vervalle
authors.forename: Mostafa
authors.initials: M
authors.lastname: Bentahir
authors.forename: Joel
authors.initials: J
authors.lastname: Vandekerckhove
authors.forename: Walter
authors.initials: W
authors.lastname: Fiers
authors.forename: Xavier
authors.initials: X
authors.lastname: Saelens
mesh_terms: D000818:Animals; D002850:Chromatography, Gel; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000737:chemistry; D007074:Immunoglobulin G / Q000737:chemistry; D007252:Influenza Vaccines / Q000737:chemistry*; D013058:Mass Spectrometry / Q000379:methods; D051379:Mice; D008807:Mice, Inbred BALB C; D008954:Models, Biological; D008968:Molecular Conformation; D010455:Peptides / Q000737:chemistry; D017434:Protein Structure, Tertiary; D014763:Viral Matrix Proteins / Q000737:chemistry*; D000086082:Viroporin Proteins
chemical_list: D000939:Epitopes; D007074:Immunoglobulin G; D007252:Influenza Vaccines; D010455:Peptides; D014763:Viral Matrix Proteins; C488937:M2 protein, Influenza A virus; D000086082:Viroporin Proteins