Table 1.
Amino acid difference and virus titers of reassortant viruses.
| Viruses | Passage historya | Amino acid residue at 220 position of HA (%)b | HA titer | logEID50/ml | LogTCID50/ml |
|---|---|---|---|---|---|
| RG-SF003 | V1E1 | R/G/I(100,0,0) | 512 | 9.0 | 7.3 |
| V1E2 | R/G/I(99,1,0) | 512 | —c | — | |
| V1E3 | R/G/I(88,10,2) | 512 | — | — | |
| V1E4 | R/G/I(35/50/15) | 1024 | — | — | |
| V1E5 | R/G/I(22/70/8) | 1024 | 9.22 | 7.87 | |
| PR8 | C1E2 | R | 1024 | 9.44 | 8.0 |
a
‘V’ Vero cells; ‘E’ eggs;’ C’ MDCK cells.
b
H3 HA numbering system was used.%: The percentage of different amino acids.
c
‘-’ denote not done. All results were determined by haemagglutination assay and calculated by the Reed–Muench method.1% turkey erythrocytes were used.