| Title |
Molecular Characterization and Phylogenetic Analysis of H3N2 Human Influenza A Viruses in Cheongju, South Korea |
| Author |
Yun Hee Baek1, Jeung Hyun Park1, Young Jun Song1, Min-Suk Song1, Philippe Noriel Q. Pascua1, Yoon-Soo Hahn1, Heon-Seok Han1, Ok-Jun Lee1, Ki-Soon Kim2, Chun Kang2, and Young-Ki Choi1* |
| Address |
1College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju 361-763, Republic of Korea, 2Division of Influenza and Respiratory Viruses, Center for Infectious Disease, National Institute of Health, Korea Center for Disease Control and Prevention, Seoul 122-701, Republic of Korea |
| Bibliography |
Journal of Microbiology, 47(1),91-100, 2009,
|
| DOI |
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| Key Words |
influenza A virus, H3N2, antigenic drift, amantadine-resistant |
| 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. |
