Table 3. HI titres of egg-propagated and cell-culture-propagated prototype, CVV and RG viruses and associated virus binding avidities to BLI receptor-analogues.
| Haemagglutination inhibition titre† Post-infection ferret antisera | Virus binding to BLI receptor-analogues‡ | ||||||
|---|---|---|---|---|---|---|---|
| Test viruses* | Vic361e | Vic361c | NIB-79V | IVR-165V | X-217V | 3-SLN | 6-SLN |
| A/Victoria/361/2011E | 2560 | 320 | 640 | 1280 | 1280 | ++ | ++ |
| A/Victoria/361/2011C | 640 | 640 | 160§ | 640 | 640 | – | – |
| NIB-79V | 1280 | 80§ | 1280 | 320 | 320 | ++ | + |
| IVR-165V | 2560 | 160 | 160§ | 1280 | 5120 | – | – |
| X-217V | 1280 | 160 | 320 | 2560 | 1280 | – | – |
| RG viruses derived from egg-propagated Vic361e | |||||||
| RG/Vic361e R156HE | 1280 | 1280 | 640 | 2560 | 2560 | – (↑) | + (↓) |
| RG/Vic361e R156QE | 640 | 320 | 640 | 2560 | 2560 | +++ (↑) | + (↓) |
| RG/Vic361e V186GE | 1280 | 1280 | 1280 | 1280 | 1280 | – (↓) | + (↓) |
| RG/Vic361e D190EE | 1280 | 160 | 2560 | 320 | 320 | ++ | + (↓) |
| RG/Vic361e S219FE | 1280 | 320 | 1280 | 640 | 640 | ++ | ++ |
| RG/Vic361e S219YE | 2560 | 320 | 1280 | 1280 | 2560 | +++ (↑) | + (↓) |
| RG/Vic361e I226NE | 1280 | 640 | 640 | 640 | 640 | ++ | + (↓) |
| RG/Vic361e R156Q+S219YE | 640 | 160 | 320 | 2560 | 2560 | – (↓) | – (↓) |
| RG viruses derived from cell-propagated Vic361c | |||||||
| RG/Vic361c H156RC | 1280 | 320 | 640 | 640 | 640 | – | ++ (↑) |
| RG/Vic361c H156QC | 640 | 160 | 320 | 1280 | 1280 | – | – |
| RG/Vic361c G186VC | 2560 | 2560 | 1280 | 1280 | 1280 | – | – |
| RG/Vic361c S219FC | 640 | 640 | 320 | 320 | 320 | – | – |
| RG/Vic361c S219YC | 640 | 320 | 320 | 640 | 1280 | – | – |
| RG/Vic361c H156Q+S219YC | 640 | 160 | 320 | 1280 | 640 | – | – |
| RG/Vic361c H156R+S219YC | 1280 | 160 | 640 | 1280 | 1280 | – | – |
*E, Egg-propagated; C, cell culture-propagated; V, CVV. †Homologous HI titres highlighted in bold text; HI titres decreased 4-fold compared to homologous titres highlighted in italic text, reductions of ≥8-fold marked with §. HI assays were repeated three times and the data presented are the modal values. Assays performed with guinea pig RBC in PBS plus 20 nM oseltamivir carboxylate. ‡Arbitrary BLI binding avidities of viruses to 3-SLN or 6-SLN analogues. +++, Very strong binding, (↑) increased binding compared with prototype; ++, strong binding; +, detectable binding; (↓), weaker binding compared with prototype; –,l no detectable binding.