TABLE 2.

TV-1 and -2 are attenuated in SCID-HuH-7 mice compared to a formulation of wild-type DEN viruses and do not show interference among individual components

InoculumanVirus titer (fold reduction) in serum determined by:
Plaque assay in Vero cells (log10 PFU/ml of serum)Serotype-specific quantitative PCR (log10 genome equivalents/ml of serum)b
DEN1DEN2DEN3DEN4
DEN198.0 ± 0.39.9 ± 0.3NDcNDND
DEN296.3 ± 0.3ND9.1 ± 0.3NDND
DEN3106.2 ± 0.3NDND8.7 ± 0.3ND
DEN477.5 ± 0.3NDNDND9.4 ± 0.3
T-wt138.2 ± 0.29.9 ± 0.28.4 ± 0.28.2 ± 0.29.3 ± 0.2
rDEN1Δ3075.1 ± 0.38.4 ± 0.2NDNDND
rDEN2Δ3055.1 ± 0.2ND7.6 ± 0.2NDND
rDEN3Δ3085.5 ± 0.3NDND8.1 ± 0.3ND
rDEN4Δ3086.3 ± 0.3NDNDND8.9 ± 0.3
TV-1126.6 ± 0.2 (1.6)d7.9 ± 0.3 (2.0)e7.0 ± 0.3 (2.1)e8.4 ± 0.4 (0.3)e8.4 ± 0.4 (1.0)e
rDEN1Δ3075.5 ± 0.28.2 ± 0.2NDNDND
rDEN2/4Δ30124.9 ± 0.3ND8.2 ± 0.3NDND
rDEN3/4Δ3095.4 ± 0.2NDND8.0 ± 0.1ND
rDEN4Δ3076.1 ± 0.4NDNDND8.8 ± 0.3
TV-2116.2 ± 0.3 (2.0)d8.0 ± 0.3 (1.9)e8.3 ± 0.3 (0.8)e7.7 ± 0.3 (1.0)e8.4 ± 0.2 (1.0)e
  • a SCID-HuH-7 mice were inoculated with an individual component virus (104 PFU) or a tetravalent formulation (104 PFU of each virus), and serum was collected on day 7.

  • b Viral RNA was isolated from serum and used in a qPCR assay with serotype-specific primers as described in Materials and Methods.

  • c ND, not detected. The limit of detection was <4.6 log10 genome equivalents/ml of serum.

  • d Reduction in mean virus titer (log10 PFU/ml of serum) of TV formulation compared to that of the T-wt formulation.

  • e Reduction in genome equivalents of each component of the TV formulation compared to that of the respective wild-type component of the T-wt formulation.