title: Heterosubtypic protective immunity against widely divergent influenza subtypes induced by fusion protein 4sM2 in BALB/c mice.
abstract: BACKGROUND
  Regular reformulation of currently available vaccines is necessary due to the unpredictable variability of influenza viruses. Therefore, vaccine based on a highly conserved antigen with capability of induction of effective immune responses could be a potential solution. Influenza matrix protein-2 (M2) is highly conserved across influenza subtypes and a promising candidate for a broadly protective influenza vaccine. For the enhancement of broad protection, four tandem copies of consensus M2 gene containing extracellular (ED) and cytoplasmic (CD) without the trans-membrane domain (TM) reconstituted from H1N1, H5N1 and H9N2 influenza viruses were linked and named as 4sM2. The construct was effectively expressed in Escherichia coli, purified and proteins were used to immunize BALB/c mice. Humoral and cell-mediated immune responses were investigated following administration.
  
  
  RESULTS
  Mice were intramuscularly immunized with 4sM2 protein 2 times at 2 weeks interval. Two weeks after the last immunization, first humoral and cell mediated immune response specific to sM2 protein were evaluated and the mice were challenged with a lethal dose (10MLD₅₀) of divergent subtypes A/EM/Korea/W149/06(H5N1), A/PR/8/34(H1N1), A/Aquatic bird/Korea/W81/2005(H5N2), A/Aquatic bird/Korea/W44/2005(H7N3), and A/Chicken/Korea/116/2004(H9N2) viruses. The efficacy of 4sM2 was evaluated by determining survival rates, body weights and residual lung viral titers. Our studies demonstrate that the survival of mice immunized with 4sM2 was significantly higher (80-100% survival) than that of unimmunized mice (0% survival). We also examined the long lasting protection against heterosubtype H5N2 virus and found that mice vaccinated with 4sM2 displayed 80% of protection even after 6 months of final vaccination.
  
  
  CONCLUSIONS
  Taken together, these results suggest that prokaryotic expressed multimeric sM2 protein achieved cross protection against lethal infection of divergent influenza subtypes which are lasting for the long time.
authors: Mohammed Y E
authors: MY
authors: Chowdhury
authors: Soo-Kyung
authors: SK
authors: Seo
authors: Ho-Jin
authors: HJ
authors: Moon
authors: Melbourne R
authors: MR
authors: Talactac
authors: Jae-Hoon
authors: JH
authors: Kim
authors: Min-Eun
authors: ME
authors: Park
authors: Hwa-Young
authors: HY
authors: Son
authors: College of Veterinary Medicine (BK21 Plus Program), Chungnam National University, Daejeon 305-764, Republic of Korea. jongsool@cnu.ac.kr.
authors: Jong-Soo
authors: JS
authors: Lee
authors: Chul-Joong
authors: CJ
authors: Kim
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D001835:Body Weight; D056738:Cross Protection; D004195:Disease Models, Animal; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D053118:Influenza A Virus, H1N1 Subtype / Q000235:genetics / Q000276:immunology; D053124:Influenza A Virus, H5N1 Subtype / Q000235:genetics / Q000276:immunology; D053127:Influenza A Virus, H9N2 Subtype / Q000235:genetics / Q000276:immunology; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D007273:Injections, Intramuscular; D007963:Leukocytes, Mononuclear / Q000276:immunology; D008168:Lung / Q000821:virology; D051379:Mice; D008807:Mice, Inbred BALB C; D009976:Orthomyxoviridae Infections / Q000276:immunology / Q000517:prevention & control*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification; D016019:Survival Analysis; D014611:Vaccination / Q000379:methods; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology; D019562:Viral Load; D014763:Viral Matrix Proteins / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D000086082:Viroporin Proteins
chemical_list: D000914:Antibodies, Viral; D007252:Influenza Vaccines; D011993:Recombinant Fusion Proteins; D014614:Vaccines, Synthetic; D014763:Viral Matrix Proteins; C488937:M2 protein, Influenza A virus; D000086082:Viroporin Proteins