TABLE 3.

Replication of rescued viruses in BALB/c mice inoculated intranasally with 106 EID50 (50 μl)a

VirusbMean virus titer (log10 EID50/ml) ± SD
LungSpleenKidneyBrain
Day 4 p.iDay 6 p.iDay 4 p.iDay 6 p.iDay 4 p.iDay 6 p.iDay 4 p.iDay 6 p.i
W-DKGX/22
W-DKGX/356.5 ± 0.16.4 ± 0.41.9 ± 0.61.4 ± 0.21.4 ± 0.31.9 ± 0.42.4 ± 1.05.7 ± 0.2
R-DKGX/22
R-DKGX/356.5 ± 0.15.9 ± 1.03.0 ± 0.42.2 ± 0.71.8 ± 1.01.6 ± 0.42.2 ± 0.45.0 ± 1.1
GX/22-35PB24.4 ± 0.44.7 ± 0.81.3 ± 03.3 ± 1.9
GX/35-22PB25.0 ± 1.63.8 ± 2.01.3 ± 0.1d2.4 ± 0.4
GX/35-22PB14.5 ± 2.76.0 ± 0.42.0 ± 0.71.9 ± 0.11.5 ± 0.41.3 ± 0.13.5 ± 0.5
GX/35-22PA5.4 ± 0.4d5.5 ± 0.11.9 ± 0.93.6 ± 1.3
GX/35-22HA6.5 ± 0.36.5 ± 0.33.0 ± 0.42.8 ± 0.11.6 ± 0.51.3 ± 03.0 ± 1.74.8 ± 0.8
GX/35-22NP6.4 ± 0.16.3 ± 0.52.8 ± 0.42.6 ± 0.12.0 ± 0.75.1 ± 0.5
GX/35-22NA5.1 ± 0.5d4.5 ± 0.31.5 ± 0.4c1.3 ± 0.11.2 ± 0.12.0 ± 1.33.2 ± 1.8
GX/35-22M5.0 ± 1.56.1 ± 0.62.2 ± 0.92.3 ± 0.71.2 ± 0.12.0 ± 1.31.4 ± 0.32.8 ± 0.8c
GX/35-22NS5.5 ± 0.75.9 ± 0.31.7 ± 0.93.6 ± 0.61.4 ± 0.14.5 ± 0.7
Chimera 1
Chimera 24.5 ± 0.54.9 ± 0.51.2 ± 0.12.5 ± 1.1
Chimera 32.8 ± 1.8c2.0 ± 1.3c
Chimera 46.2 ± 0.75.3 ± 1.41.6 ± 0.5c1.3 ± 0.11.3 ± 0.12.6 ± 1.82.6 ± 1.4
22/PB2-699K
22/PB2-701N3.6 ± 0.62.4 ± 2.01.6 ± 0.7
35/PB2-699N5.2 ± 0.1d4.2 ± 2.61.5 ± 0.3d2.3 ± 0.91.2 ± 0.11.3 ± 0.1c1.7 ± 0.9c
35/PB2-701D2.5 ± 1.3d6.1 ± 1.21.5 ± 0.2
  • a Three mice from each group were killed on days 4 and 6 postinoculation (p.i.), and virus in the organs was titrated in eggs. Blank cells indicate no virus detected.

  • b Reassortant viruses bearing the PB1, PA, HA, NP, NA, M, and NS genes in the DKGX/22 background were not recovered from any organ of the inoculated mice on day 4 or day 6, and therefore, the data are not shown.

  • c P < 0.05 compared with the titers in the corresponding organs of the R-DKGX/35-inoculated mice.

  • d P < 0.01 compared with the titers in the corresponding organs of the R-DKGX/35-inoculated mice.