title: Robust immunity and heterologous protection against influenza in mice elicited by a novel recombinant NP-M2e fusion protein expressed in E. coli.
abstract: BACKGROUND
  The 23-amino acid extracellular domain of matrix 2 protein (M2e) and the internal nucleoprotein (NP) of influenza are highly conserved among viruses and thus are promising candidate antigens for the development of a universal influenza vaccine. Various M2e- or NP-based DNA or viral vector vaccines have been shown to have high immunogenicity; however, high cost, complicated immunization procedures, and vector-specific antibody responses have restricted their applications. Immunization with an NP-M2e fusion protein expressed in Escherichia coli may represent an alternative strategy for the development of a universal influenza vaccine.
  
  
  RESULTS
  cDNA encoding M2e was fused to the 3' end of NP cDNA from influenza virus A/Beijing/30/95 (H3N2). The fusion protein (NM2e) was expressed in E. coli and isolated with 90% purity. Mice were immunized with recombinant NM2e protein along with aluminum hydroxide gel and/or CpG as adjuvant. NM2e plus aluminum hydroxide gel almost completely protected the mice against a lethal (20 LD(50)) challenge of heterologous influenza virus A/PR/8/34.
  
  
  CONCLUSIONS
  The NM2e fusion protein expressed in E. coli was highly immunogenic in mice. Immunization with NM2e formulated with aluminum hydroxide gel protected mice against a lethal dose of a heterologous influenza virus. Vaccination with recombinant NM2e fusion protein is a promising strategy for the development of a universal influenza vaccine.
authors.affiliation: National Institute for Viral Disease Control & Prevention, Chinese Center for Disease Control and Prevention, China CDC, Beijing, People's Republic of China.
authors.forename: Wenling
authors.initials: W
authors.lastname: Wang
authors.forename: Baoying
authors.initials: B
authors.lastname: Huang
authors.forename: Tao
authors.initials: T
authors.lastname: Jiang
authors.forename: Xiuping
authors.initials: X
authors.lastname: Wang
authors.forename: Xiangrong
authors.initials: X
authors.lastname: Qi
authors.forename: Yingying
authors.initials: Y
authors.lastname: Gao
authors.forename: Wenjie
authors.initials: W
authors.lastname: Tan
authors.forename: Li
authors.initials: L
authors.lastname: Ruan
mesh_terms: D000818:Animals; D000917:Antibody Formation / Q000276:immunology; D004926:Escherichia coli / Q000378:metabolism*; D007109:Immunity / Q000276:immunology*; D007111:Immunity, Cellular / Q000276:immunology; D056724:Immunity, Humoral; D007114:Immunization; D007074:Immunoglobulin G / Q000097:blood; D009980:Influenza A virus / Q000276:immunology*; D051379:Mice; D009698:Nucleoproteins / Q000276:immunology*; D009976:Orthomyxoviridae Infections / Q000097:blood / Q000276:immunology / Q000517:prevention & control* / Q000821:virology; D011993:Recombinant Fusion Proteins / Q000276:immunology* / Q000302:isolation & purification; D016019:Survival Analysis; D016896:Treatment Outcome; D014763:Viral Matrix Proteins / Q000276:immunology*
chemical_list: D007074:Immunoglobulin G; D009698:Nucleoproteins; D011993:Recombinant Fusion Proteins; D014763:Viral Matrix Proteins