title: Pandemic influenza vaccine: characterization of A/California/07/2009 (H1N1) recombinant hemagglutinin protein and insights into H1N1 antigen stability.
abstract: BACKGROUND
  The recent H1N1 influenza pandemic illustrated the shortcomings of the vaccine manufacturing process. The A/California/07/2009 H1N1 pandemic influenza vaccine or A(H1N1)pdm09 was available late and in short supply as a result of delays in production caused by low yields and poor antigen stability. Recombinant technology offers the opportunity to shorten manufacturing time. A trivalent recombinant hemagglutinin (rHA) vaccine candidate for seasonal influenza produced using the baculovirus expression vector system (BEVS) was shown to be as effective and safe as egg-derived trivalent inactivated vaccine (TIV) in human clinical studies. In this study, we describe the characterization of the A/California/07/2009 rHA protein and compare the H1N1 pandemic rHA to other seasonal rHA proteins.
  
  
  RESULTS
  Our data show that, like other rHA proteins, purified A/California/07/2009 rHA forms multimeric rosette-like particles of 20-40 nm that are biologically active and immunogenic in mice as assayed by hemagglutination inhibition (HAI) antibody titers. However, proteolytic digest analysis revealed that A/California/07/2009 rHA is more susceptible to proteolytic degradation than rHA proteins derived from other seasonal influenza viruses. We identified a specific proteolytic site conserved across multiple hemagglutinin (HA) proteins that is likely more accessible in A/California/07/2009 HA, possibly as a result of differences in its protein structure, and may contribute to lower antigen stability.
  
  
  CONCLUSIONS
  We conclude that, similar to the recombinant seasonal influenza vaccine, recombinant A(H1N1)pdm09 vaccine is likely to perform comparably to licensed A(H1N1)pdm09 vaccines and could offer manufacturing advantages.
authors.affiliation: Protein Sciences Corporation, 1000 Research Parkway, Meriden, CT 06450, USA.
authors.forename: Elena
authors.initials: E
authors.lastname: Feshchenko
authors.forename: David G
authors.initials: DG
authors.lastname: Rhodes
authors.forename: Rachael
authors.initials: R
authors.lastname: Felberbaum
authors.forename: Clifton
authors.initials: C
authors.lastname: McPherson
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Rininger
authors.forename: Penny
authors.initials: P
authors.lastname: Post
authors.forename: Manon M J
authors.initials: MM
authors.lastname: Cox
mesh_terms: D000595:Amino Acid Sequence; D000941:Antigens / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000378:metabolism*; D007252:Influenza Vaccines / Q000276:immunology*; D007251:Influenza, Human / Q000453:epidemiology / Q000517:prevention & control*; D008027:Light; D008969:Molecular Sequence Data; D058873:Pandemics; D055550:Protein Stability; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D012542:Scattering, Radiation; D016415:Sequence Alignment
chemical_list: D000941:Antigens; C543345:H1N1 virus hemagglutinin; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D007252:Influenza Vaccines; D011994:Recombinant Proteins