title: Molecular characterization and phylogenetic analysis of H3N2 human influenza A viruses in Cheongju, South Korea.
abstract: To investigate the genetic characteristics of human influenza viruses circulating in Chungbuk province, we tested 510 clinical samples of nasopharyngeal suction from pediatric patients diagnosed with respiratory illness between June 2007 and June 2008. Genetic characterization of the HA genes of H3N2 isolates indicated the relative higher similarity to A/Virginia/04/07 (99.6%) rather than that of A/Wisconsin/67/2005 (98.4%), a Northern Hemisphere 2007-2008 vaccine strain, based on amino acid sequences. We found several altered amino acids at the H3 HA1 antigenic sites compared with the vaccine strain; K140I at site A, K158R at site B, and K173N (H471) or K173Q, and S262N at site E, but there was no antigenic shift among the H3N2 viruses. Interestingly, A/Cheongju/H383/08 and A/Cheongju/H407/08 isolates had single amino acid substitution at D151G on the catalytic site of the N2 NA while A/Cheongju/H412/08 and A/Cheongju/ H398/07 isolates had one amino acid deletion at residue 146. Furthermore, we found that 25% (3 out of 12 isolates) of the H3N2 subtype viruses had the amino acid substitution at position 31 on the M2 protein (Aspartic acid to Asparagine) and confirmed their drug-resistance by biological assays. Taken together, the results of this study demonstrated continuous evolutions of human H3N2 viruses by antigenic drift and also highlighted the need to closely monitor antigenic drug resistance in influenza A viruses to aid in the early detection of potentially pandemic strains, as well as underscore the need for new therapeutics.
authors.affiliation: College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju 361-763, Republic of Korea.
authors.forename: Yun Hee
authors.initials: YH
authors.lastname: Baek
authors.forename: Jeung Hyun
authors.initials: JH
authors.lastname: Park
authors.forename: Young Jun
authors.initials: YJ
authors.lastname: Song
authors.forename: Min-Suk
authors.initials: MS
authors.lastname: Song
authors.forename: Philippe Noriel Q
authors.initials: PN
authors.lastname: Pascua
authors.forename: Yoon-Soo
authors.initials: YS
authors.lastname: Hahn
authors.forename: Heon-Seok
authors.initials: HS
authors.lastname: Han
authors.forename: Ok-Jun
authors.initials: OJ
authors.lastname: Lee
authors.forename: Ki-Soon
authors.initials: KS
authors.lastname: Kim
authors.forename: Chun
authors.initials: C
authors.lastname: Kang
authors.forename: Young-Ki
authors.initials: YK
authors.lastname: Choi
mesh_terms: D000293:Adolescent; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D000940:Antigenic Variation; D002460:Cell Line; D002648:Child; D002675:Child, Preschool; D004279:DNA, Viral / Q000032:analysis; D004285:Dogs; D004791:Enzyme Inhibitors / Q000494:pharmacology; D019143:Evolution, Molecular; D006801:Humans; D007223:Infant; D053122:Influenza A Virus, H3N2 Subtype / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D007251:Influenza, Human / Q000235:genetics / Q000821:virology; D007723:Korea; D037102:Lectins / Q000235:genetics; D008969:Molecular Sequence Data; D009305:Nasopharynx / Q000821:virology; D009439:Neuraminidase / Q000172:deficiency / Q000235:genetics; D053139:Oseltamivir / Q000494:pharmacology; D010802:Phylogeny
chemical_list: D004279:DNA, Viral; D004791:Enzyme Inhibitors; D037102:Lectins; C112408:hemagglutinin I; D053139:Oseltamivir; D009439:Neuraminidase