title: Identification of dual receptor-binding specific strains of human H5N1 viruses in China.
abstract: OBJECTIVE
  Both the 2, 6 linkage and its topology on target cells are critical for the recognition by human influenza virus. The binding preference of avian flu virus H5N1 HA to the 2, 3-linked sialylated glycans is considered the major factor limiting its efficient infection and transmission in humans. To monitor potential adaptation of H5N1 virus in human population, the surveillance of receptor-binding specificity was undertaken in China.
  
  
  METHODS
  The binding specificity of 32 human H5N1 virus strains isolated from 2003 to 2009 was tested by 2, 3-specific sialidase-treated chicken red blood cell (CRBC) agglutination assay and a solid-phase direct binding assay with synthetic sialylglycopolymers.
  
  
  RESULTS
  Dual binding preference to 2, 3 and 2, 6-glycans were found in two strains: A/Guangdong/1/06 (A/GD/1/06) and A/Guangxi/1/08 (A/GX/1/08). Though minor effect of short-2, 6-binding was detected in A/GX/1/08 at a low virus titer, both showed high affinity to the oligosaccharide at a high load. Notably both are of the long-2, 6-recognition, with the same topology as that of human H1N1 and H3N2 viruses.
  
  
  CONCLUSIONS
  The findings suggest that human H5N1 virus in China likely acquired the potential human-adaptation ability. Further research and surveillance on receptor-binding specificity of H5N1 viruses are required.
authors.affiliation: State Key Laboratory for Molecular Virology and Genetic Engineering, National Institute for Viral Disease Control and Prevention, China CDC, Beijing, China.
authors.forename: Jian Fang
authors.initials: JF
authors.lastname: Zhou
authors.forename: Shu Mei
authors.initials: SM
authors.lastname: Zou
authors.forename: Zi
authors.initials: Z
authors.lastname: Li
authors.forename: Min
authors.initials: M
authors.lastname: Wang
authors.forename: Jie
authors.initials: J
authors.lastname: Dong
authors.forename: Jun Feng
authors.initials: JF
authors.lastname: Guo
authors.forename: He Jiang
authors.initials: HJ
authors.lastname: Wei
authors.forename: Le Ying
authors.initials: le Y
authors.lastname: Wen
authors.forename: Hong
authors.initials: H
authors.lastname: Xu
authors.forename: Yue Long
authors.initials: YL
authors.lastname: Shu
mesh_terms: D000220:Adaptation, Biological; D000818:Animals; D002645:Chickens; D002681:China / Q000453:epidemiology; D006386:Hemagglutination Tests; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000378:metabolism*; D007251:Influenza, Human / Q000453:epidemiology; D011134:Polysaccharides / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000378:metabolism*; D011991:Receptors, Virus / Q000378:metabolism*; D012794:Sialic Acids / Q000378:metabolism*
chemical_list: D011134:Polysaccharides; D011956:Receptors, Cell Surface; D011991:Receptors, Virus; D012794:Sialic Acids; C092488:sialic acid receptor