Research Open Access
Like 0


Background: Influenza A(H3N2) virus rapidly evolves to evade human immune responses, resulting in changes in the antigenicity of haemagglutinin (HA). Therefore, continuous genetic and antigenic analyses of A(H3N2) virus are necessary to detect antigenic mutants as quickly as possible.

Aim: We attempted to phylogenetically and antigenically capture the epidemic trend of A(H3N2) virus infection in Yokohama, Japan during the 2016/17 and 2017/18 influenza seasons.

Methods: We determined the HA sequences of A(H3N2) viruses detected in Yokohama, Japan during the 2016/17 and 2017/18 influenza seasons to identify amino acid substitutions and the loss or gain of potential N-glycosylation sites in HA, both of which potentially affect the antigenicity of HA. We also examined the antigenicity of isolates using ferret antisera obtained from experimentally infected ferrets.

Results: Influenza A(H3N2) viruses belonging to six clades (clades 3C.2A1, 3C.2A1a, 3C.2A1b, 3C.2A2, 3C.2A3 and 3C.2A4) were detected during the 2016/17 influenza season, whereas viruses belonging to two clades (clades 3C.2A1b and 3C.2A2) dominated during the 2017/18 influenza season. The isolates in clades 3C.2A1a and 3C.2A3 lost one N-linked glycosylation site in HA relative to other clades. Antigenic analysis revealed antigenic differences among clades, especially clade 3C.2A2 and 3C.2A4 viruses, which showed distinct antigenic differences from each other and from other clades in the antigenic map.

Conclusion: Multiple clades, some of which differed antigenically from others, co-circulated in Yokohama, Japan during the 2016/17 and 2017/18 influenza seasons.


Article metrics loading...

Loading full text...

Full text loading...



  1. Nair H, Brooks WA, Katz M, Roca A, Berkley JA, Madhi SA, et al. Global burden of respiratory infections due to seasonal influenza in young children: a systematic review and meta-analysis. Lancet. 2011;378(9807):1917-30.  https://doi.org/10.1016/S0140-6736(11)61051-9  PMID: 22078723 
  2. Wiley DC, Wilson IA, Skehel JJ. Structural identification of the antibody-binding sites of Hong Kong influenza haemagglutinin and their involvement in antigenic variation. Nature. 1981;289(5796):373-8.  https://doi.org/10.1038/289373a0  PMID: 6162101 
  3. Both GW, Sleigh MJ, Cox NJ, Kendal AP. Antigenic drift in influenza virus H3 hemagglutinin from 1968 to 1980: multiple evolutionary pathways and sequential amino acid changes at key antigenic sites. J Virol. 1983;48(1):52-60. PMID: 6193288 
  4. Smith DJ, Lapedes AS, de Jong JC, Bestebroer TM, Rimmelzwaan GF, Osterhaus AD, et al. Mapping the antigenic and genetic evolution of influenza virus. Science. 2004;305(5682):371-6.  https://doi.org/10.1126/science.1097211  PMID: 15218094 
  5. Koel BF, Burke DF, Bestebroer TM, van der Vliet S, Zondag GC, Vervaet G, et al. Substitutions near the receptor binding site determine major antigenic change during influenza virus evolution. Science. 2013;342(6161):976-9.  https://doi.org/10.1126/science.1244730  PMID: 24264991 
  6. Abe Y, Takashita E, Sugawara K, Matsuzaki Y, Muraki Y, Hongo S. Effect of the addition of oligosaccharides on the biological activities and antigenicity of influenza A/H3N2 virus hemagglutinin. J Virol. 2004;78(18):9605-11.  https://doi.org/10.1128/JVI.78.18.9605-9611.2004  PMID: 15331693 
  7. Skehel JJ, Stevens DJ, Daniels RS, Douglas AR, Knossow M, Wilson IA, et al. A carbohydrate side chain on hemagglutinins of Hong Kong influenza viruses inhibits recognition by a monoclonal antibody. Proc Natl Acad Sci USA. 1984;81(6):1779-83.  https://doi.org/10.1073/pnas.81.6.1779  PMID: 6584912 
  8. European Centre for Disease Prevention and Control (ECDC). Surveillance report. Influenza characterisation. Summary Europe, June 2013. Stockholm: ECDC; 2013. Available from: https://ecdc.europa.eu/sites/portal/files/media/en/publications/Publications/influenza-virus-characterisation-june-2013.pdf
  9. European Centre for Disease Prevention and Control (ECDC). Surveillance report. Influenza characterisation. Summary Europe, June 2015. Stockholm: ECDC; 2015. Available from: https://ecdc.europa.eu/sites/portal/files/media/en/publications/Publications/influenza-virus-characterisation-June-2015.pdf
  10. Review of the 2014 influenza season in the southern hemisphere. Wkly Epidemiol Rec. 2014;89(48):529-41. PMID: 25469379 
  11. Sugaya N, Shinjoh M, Kawakami C, Yamaguchi Y, Yoshida M, Baba H, et al. Trivalent inactivated influenza vaccine effective against influenza A(H3N2) variant viruses in children during the 2014/15 season, Japan. Euro Surveill. 2016;21(42):30377.
  12. Infectious ASR. (IASR). Volume 37. Number 11 (number 441). November 2016. Infectious Agents surveillance report. Influenza 2015/16 season, Japan. PLACE; IASR; Nov 2016. Available from: https://www0.niid.go.jp/niid/idsc/iasr/37/441e.pdf#search=%27influenza+virus+2015+2016+japan%27
  13. World Health Organization (WHO). WHO recommendations on the composition of influenza virus vaccines. Geneva: WHO; Last accessed Jan 2019. Available from: http://www.who.int/influenza/vaccines/virus/recommendations/en/
  14. Nakauchi M, Yasui Y, Miyoshi T, Minagawa H, Tanaka T, Tashiro M, et al. One-step real-time reverse transcription-PCR assays for detecting and subtyping pandemic influenza A/H1N1 2009, seasonal influenza A/H1N1, and seasonal influenza A/H3N2 viruses. J Virol Methods. 2011;171(1):156-62.  https://doi.org/10.1016/j.jviromet.2010.10.018  PMID: 21029748 
  15. Hatakeyama S, Sakai-Tagawa Y, Kiso M, Goto H, Kawakami C, Mitamura K, et al. Enhanced expression of an alpha2,6-linked sialic acid on MDCK cells improves isolation of human influenza viruses and evaluation of their sensitivity to a neuraminidase inhibitor. J Clin Microbiol. 2005;43(8):4139-46.  https://doi.org/10.1128/JCM.43.8.4139-4146.2005  PMID: 16081961 
  16. Matrosovich M, Matrosovich T, Carr J, Roberts NA, Klenk HD. Overexpression of the alpha-2,6-sialyltransferase in MDCK cells increases influenza virus sensitivity to neuraminidase inhibitors. J Virol. 2003;77(15):8418-25.  https://doi.org/10.1128/JVI.77.15.8418-8425.2003  PMID: 12857911 
  17. Japan SLC. Inc (SLC). Shizuoka: SLC; last accessed Jan 2019. Available from: http://www.jslc.co.jp/english/company/
  18. Russell CA, Jones TC, Barr IG, Cox NJ, Garten RJ, Gregory V, et al. The global circulation of seasonal influenza A (H3N2) viruses. Science. 2008;320(5874):340-6.  https://doi.org/10.1126/science.1154137  PMID: 18420927 
  19. Igarashi M, Ito K, Kida H, Takada A. Genetically destined potentials for N-linked glycosylation of influenza virus hemagglutinin. Virology. 2008;376(2):323-9.  https://doi.org/10.1016/j.virol.2008.03.036  PMID: 18456302 
  20. Harvala H, Frampton D, Grant P, Raffle J, Ferns RB, Kozlakidis Z, et al. Emergence of a novel subclade of influenza A(H3N2) virus in London, December 2016 to January 2017. Euro Surveill. 2017;22(8):30466.
  21. Suntronwong N, Klinfueng S, Vichiwattana P, Korkong S, Thongmee T, Vongpunsawad S, et al. Genetic and antigenic divergence in the influenza A(H3N2) virus circulating between 2016 and 2017 in Thailand. PLoS One. 2017;12(12):e0189511.  https://doi.org/10.1371/journal.pone.0189511  PMID: 29252990 
  22. Skowronski DM, Chambers C, De Serres G, Dickinson JA, Winter AL, Hickman R, et al. Early season co-circulation of influenza A(H3N2) and B(Yamagata): interim estimates of 2017/18 vaccine effectiveness, Canada, January 2018. Euro Surveill. 2018;23(5):18-00035.
  23. Sullivan SG, Chilver MB, Carville KS, Deng YM, Grant KA, Higgins G, et al. Low interim influenza vaccine effectiveness, Australia, 1 May to 24 September 2017. Euro Surveill. 2017;22(43):17-00707.
  24. Tsou TP, Su CP, Huang WT, Yang JR, Liu MT. Influenza A(H3N2) virus variants and patient characteristics during a summer influenza epidemic in Taiwan, 2017. Euro Surveill. 2017;22(50):17-00767.
  25. Zost SJ, Parkhouse K, Gumina ME, Kim K, Diaz Perez S, Wilson PC, et al. Contemporary H3N2 influenza viruses have a glycosylation site that alters binding of antibodies elicited by egg-adapted vaccine strains. Proc Natl Acad Sci USA. 2017;114(47):12578-83.  https://doi.org/10.1073/pnas.1712377114  PMID: 29109276 

Data & Media loading...

Submit comment
Comment moderation successfully completed
This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error