Table 1.
Susceptibility of Human H7N9 and Avian N9 Influenza Viruses to Neuraminidase Inhibitors
| Influenza Virus | Subtype | Passage Historya | NA Enzyme Inhibition Assay (Mean IC50 ± SD, nM)b |
||
|---|---|---|---|---|---|
| Oseltamivir Carboxylate | Zanamivir | Peramivir | |||
| Human H7N9 viruses | |||||
| A/Anhui/1/2013 | H7N9 | E3 | 0.33 ± 0.07 | 0.96 ± 0.19 | 0.15 ± 0.03 |
| A/Shanghai/1/2013 | H7N9 | E3 | 0.51 ± 0.01 | 0.82 ± 0.13 | 0.13 ± 0.01 |
| A/Shanghai/1/2013 | H7N9 | E4 | 0.32 ± 0.01 | 0.38 ± 0.30 | 0.20 ± 0.06 |
| A/Shanghai/2/2013 | H7N9 | E4 | 0.34 ± 0.04 | 0.71 ± 0.01 | 0.13 ± 0.03 |
| Avian N9 viruses | |||||
| A/Wild Duck/Shantou/520/2001 | H1N9 | E3 | 0.49 ± 0.02 | 0.89 ± 0.18 | 0.15 ± 0.01 |
| A/Duck/Nanchang/2-0492/2000 | H2N9 | E7 | 0.48 ± 0.09 | 0.86 ± 0.30 | 0.13 ± 0.02 |
| A/Mallard/Alberta/31/2001 | H3N9 | E3 | 0.44 ± 0.05 | 1.41 ± 0.20 | 0.24 ± 0.03 |
| A/Mallard/Alberta/507/2010 | H4N9 | E3 | 0.56 ± 0.12 | 0.87 ± 0.12 | 0.15 ± 0.01 |
| A/Goose/Hong Kong/W217/1997 | H6N9 | E5 | 0.52 ± 0.06 | 0.84 ± 0.07 | 0.15 ± 0.0 |
| A/Turkey/Minnesota/1/1988 | H7N9 | E3 | 0.41 ± 0.04 | 0.87 ± 0.08 | 0.11 ± 0.01 |
| A/Turkey/Minnesota/037767/2009 | H7N9 | E4 | 0.52 ± 0.07 | 0.94 ± 0.08 | 0.14 ± 0.01 |
| A/Duck/Bangladesh/8988/2010 | H10N9 | E2 | 0.35 ± 0.25 | 0.32 ± 0.36 | 0.10 ± 0.05 |
| A/Mallard/Alberta/122/1999 | H11N9 | E4 | 0.49 ± 0.09 | 0.85 ± 0.04 | 0.17 ± 0.01 |
| A/Mallard/Vietnam/66MD/2004 | H12N9 | E3 | 0.57 ± 0.13 | 0.92 ± 0.12 | 0.18 ± 0.01 |
| A/Herring Gull/Delaware/142/2007 | H13N9 | E1(Duck)/E2 | 0.49 ± 0.04 | 1.01 ± 0.09 | 0.17 ± 0.01 |
| A/Australian Shelduck/Western Australia/1762/1983 | H15N9 | E2 | 0.54 ± 0.06 | 1.66 ± 0.24 | 0.23 ± 0.01 |
| Reference viruses | |||||
| A/Fukui/20/2004-WTc | H3N2 | CX/C1 | 0.30 ± 0.15 | 0.52 ± 0.50 | 0.37 ± 0.20 |
| A/Fukui/45/2004-E119Vc | H3N2 | CX/C1 | 35.03 ± 16.32 | 0.76 ± 0.36 | 0.19 ± 0.03 |
Abbreviations: IC50, 50% inhibitory concentration; NA, neuraminidase; WT, wild-type.
a Indicates that virus was propagated in embryonated chicken (or duck) eggs, E; or in Madin-Darby canine kidney cells, C. Number indicates number of passages, X is unknown number.
b Concentration of neuraminidase inhibitor that reduced viral NA activity by 50% relative to NA activity without inhibitor. Values represent the mean ± SD from 2 independent experiments performed in triplicate.
c Oseltamivir-susceptible A/Fukui/20/2004 (H3N2) virus (WT) and oseltamivir-resistant A/Fukui/45/2004 (H3N2) virus carrying an E119V NA mutation were obtained from the Antiviral Group, International Society for Influenza and Other Respiratory Virus Diseases, and were included as internal controls for the standardization of IC50 values.