title: Cross-reactive antibodies against H7N9 and H5N1 avian influenza viruses in Thai population.
abstract: BACKGROUND
  Avian influenza H5N1 and H7N9 viruses have jumped across species from avian to humans and become a threat to public health. Not much is known about pre-existing cross-reactive antibodies against these avian viruses in human population.
  
  
  OBJECTIVE
  To determine the prevalence of cross-reactive anti-HA and anti-NA antibodies to avian influenza H5N1 and H7N9 viruses in Thai population.
  
  
  METHODS
  Archival serum samples from 100 blood donors and 21 patients infected with 2009 pandemic influenza A (H1N1) (pdmH1N1) virus were investigated by hemagglutination-inhibition (HAI) and neuraminidase-inhibition (NAI) assays for anti-HA and anti-NA antibodies, respectively. The test antigens comprised 2 human viruses (pdmH1N1 and H3N2 viruses), and 6 reassortant viruses carrying HA and NA genes of avian H5N1 or H7N9 virus generated by reverse genetics.
  
  
  RESULTS
  HAI antibody titers ≥ 10 were found in 58, 89, 0 and 15% of blood donors as tested against pdmH1N1, H3N2, H5N1 and H7N9 viruses, respectively. On the other hand, NAI antibodies were detected in 98, 94, 73 and 53% of blood donors when reverse genetic-derived viruses harboring NA gene from pdmH1N1, H3N2, H5N1 or H7N9 virus were used as the test antigens. Moreover, 66.7% of pdmH1N1 patients who had > 4 fold increase in HAI antibody titers in paired sera developed > 4 fold increase in NAI antibody titers.
  
  
  CONCLUSIONS
  Anti-NA antibody has broader reactivity than anti-HA antibody, therefore, it can be a supplement to anti-HA antibody in the prevention against novel influenza viruses.
authors.affiliation: Department of Microbiology, Faculty of Medicine Siriraj Hospital, Mahidol University.
authors.forename: Li
authors.initials: L
authors.lastname: Jiang
authors.affiliation: Department of Microbiology, Faculty of Medicine Siriraj Hospital, Mahidol University.
authors.forename: Don
authors.initials: D
authors.lastname: Changsom
authors.affiliation: Center of Research and Innovation, Faculty of Medical Technology, Mahidol University.
authors.forename: Hatairat
authors.initials: H
authors.lastname: Lerdsamran
authors.affiliation: Department of Microbiology, Faculty of Medicine Siriraj Hospital, Mahidol University.
authors.forename: Wanibtisam
authors.initials: W
authors.lastname: Masamae
authors.affiliation: National Science and Technology Development Agency, Ministry of Science.
authors.forename: Anan
authors.initials: A
authors.lastname: Jongkaewwattana
authors.affiliation: Bureau of Epidemiology, Ministry of Public Health.
authors.forename: Sopon
authors.initials: S
authors.lastname: Iamsirithaworn
authors.affiliation: The National Blood Center, The Thai Red Cross Society.
authors.forename: Sineenat
authors.initials: S
authors.lastname: Oota
authors.affiliation: Department of Microbiology, Faculty of Medicine Siriraj Hospital, Mahidol University.
authors.forename: Suda
authors.initials: S
authors.lastname: Louisirirotchanakul
authors.affiliation: Department of Microbiology, Faculty of Medicine Siriraj Hospital, Mahidol University.|Center for Emerging and Neglected Infectious Disease, Mahidol University.
authors.forename: Prasert
authors.initials: P
authors.lastname: Auewarakul
authors.affiliation: Department of Microbiology, Faculty of Medicine Siriraj Hospital, Mahidol University.|Center of Research and Innovation, Faculty of Medical Technology, Mahidol University.|Center for Emerging and Neglected Infectious Disease, Mahidol University.
authors.forename: Pilaipan
authors.initials: P
authors.lastname: Puthavathana
mesh_terms: D000914:Antibodies, Viral / Q000276:immunology*; D003429:Cross Reactions; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D053124:Influenza A Virus, H5N1 Subtype / Q000276:immunology*; D064766:Influenza A Virus, H7N9 Subtype / Q000276:immunology*; D013785:Thailand
chemical_list: D000914:Antibodies, Viral