Table 1. Antigenic properties of study samples measured by HI assays using ferret or sheep antisera raised against contemporary influenza A(H3N2) strains.
| HA GenBank or EpiFlua accession number | HA clade | Antigens used to generate ferret sera | Antigens used to generate sheep sera | |||||
|---|---|---|---|---|---|---|---|---|
| rA/Perth/16/2009 | rA/Victoria/361/2011-likeb (cell-grown) | rA/Victoria/361/2011 (egg-grown) | rA/Indiana/8/2011 (H3N2v) | A/Victoria/361/2011 | A/Texas/50/2012 | |||
| Reference antigensc | ||||||||
| rA/Perth/16/2009 (cell-grown) | GQ293081.1 | 1 | 320 | 320 | 113 | <20 | 453 | 1,280 |
| rA/Victoria/361/2011 (cell-grown) | EPI349103 | 3C.1 | 640 | 453 | 538 | 20 | 905 | >2,560 |
| rA/Victoria/361/2011 (egg-grown) | EPI353906 | 3C.1 | 226 | 320 | 905 | 40 | 1,280 | >2,560 |
| rA/Indiana/8/2011 (H3N2v) | JN638733.1 | N/A | <20 | <20 | <20 | 320 | <80 | <80 |
| Test antigens | ||||||||
| A/Texas/JMM_3/2012 | CY134748.1 | 5 | 226 | 453 | 113 | <20 | 320 | 1,810 |
| A/Texas/JMM_48/2012 | CY135076.1 | 3A | 226 | 57 | 160 | <20 | <80 | 905 |
| A/Texas/JMM_20/2012 | CY134868.1 | 3C.2 | 320 | 226 | 320 | <20 | 320 | 1,810 |
| A/Texas/JMM_37/2012 | CY134996.1 | 3C.3 | 80 | <20 | 28 | <20 | <80 | <80 |
| A/Texas/JMM_4/2012 | CY134756.1 | 3C-2012/13 | 80 | <20 | 40 | <20 | <80 | <80 |
HA: haemagglutinin; NA: neuraminidase; N/A: not applicable.
The authors gratefully acknowledge the originating (WHO Collaborating Centre for Reference and Research on Influenza in North Melbourne, Victoria, Australia) and submitting (Centers for Disease Control and Prevention, Atlanta, Georgia, US) laboratories that contributed the cell-and egg-grown A/Victoria/361/2011 sequences to GISAID's EpiFlu database.
rA/South_Australia/3/2011, which has the same amino acid sequence as A/Victoria/361/2011 (cell-grown) except for one change in the signal peptide.
These reassortant viruses are named for the strain from which the HA and NA were obtained; the six internal genes match A/Puerto Rico/8/1934(H1N1), A/New York/238/2005(H3N2) or A/New York/1682/2009(H1N1pdm09) sequences.
Highlighted cells indicate two-way HI results, where the specified serum is tested using the same (or a very similar) antigen to that used to generate the serum. An ‘r’ before the strain name indicates the virus was generated using gene synthesis and reverse genetics. Results from one experimental replicate are presented and are representative of the results obtained from at least two additional experimental replicates performed on a different day. All HA controls were between 3 and 8 HA units.