Table 1.
Virulence of mouse-adapted isolates of A/HK/1/68
| A/HK/1/68 viruses passaged in mouse lung | LD50, pfu | Change in LD50 (LOG10 decrease) |
|---|---|---|
| Unpassaged A/HK/1/68 parent clone HK | >107.7 | NA |
| Passage 12 population | 103.7 | >4.0 |
| Passage 12 clone HKMA12 | 104.0 | >3.7 |
| Passage 12 clone HKMA12A | 103.9 | >3.8 |
| Passage 12 clone HKMA12B | 103.6 | >4.1 |
| Passage 12 clone HKMA12C | 104.6 | >3.1 |
| Passage 12 clone HKMA12D | >104.7 | ND |
| Passage 12 clone HKMA12E | >104.9 | ND |
| Passage 20 population | 102.7* | >5.0 |
| Passage 20 clone HKMA20 | 104.2 | >3.5 |
| Passage 20 clone HKMA20A | 104.0 | >3.7 |
| Passage 20 clone HKMA20B | 103.0* | >4.7 |
| Passage 20 clone HKMA20C | 102.6±0.3 | >5.1 |
| Passage 20 clone HKMA20D | 103.5 | >4.2 |
| Passage 20 clone HKMA20E | 103.6 | >4.1 |
*
, viruses not significantly different in virulence relative to HKMA20C, (Z value, P ≤ 0.05); NA, not applicable; ND, not done.