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Table 2 Level of temperature sensitivity of replication of rHPIV1 mutants in vitro.

From: Attenuation and efficacy of human parainfluenza virus type 1 (HPIV1) vaccine candidates containing stabilized mutations in the P/C and L genes

    Mean reduction (log10) in virus titer ± S.E. at the indicated temperature compared to 32°Cc  
Virusa Virus titer ± S.E. at 32°Cb 35°C 36°C 37°C 38°C 39°C 40°C Shut-off (°C)d
1 HPIV1 wt 7.7 ± 0.1 0.1 ± 0.1 0.1 ± 0.1 0.2 ± 0.1 0.7 ± 0.1 1.3 ± 0.1 3.0 ± 0.3 -
2e rHPIV1-CR84G 9.2 ± 0.4 0.4 ± 0.2 0.4 ± 0.6 0.8 ± 0.5 0.3 ± 0.4 1.8 ± 0.6 4.5 ± 0.9 -
3e rHPIV1-CR84GHNT553A 7.8 ± 0.1 -0.3 ± 0.2 -0.3 ± 0.2 -0.2 ± 0.2 0.1 ± 0.2 0.7 ± 0.2 2.5 ± 0.6 -
4e rHPIV1-CΔ170 7.9 ± 0.3 0.2 ± 0.2 0.7 ± 0.8 0.5 ± 0.2 1.0 ± 0.3 2.6 ± 0.7 4.5 ± 1.0 -
5 rHPIV1-LY942A 8.0 ± 0.1 0.2 ± 0.3 1.2 ± 0.3 2.6 ± 1.1 c,d 6.4 ± 0.4 6.8 f 6.8 37°C
6e rHPIV1-CR84GHNT553ALY942A 7.4 ± 0.2 0.4 ± 0.4 0.5 ± 0.4 2.3 ± 0.4 4.0 ± 0.6 6.0 ± 0.4 6.4 37°C
7 rHPIV1-CR84GLΔ1710–11 7.5 ± 0.7 0.8 ± 0.7 3.0 ± 0.6 4.8 ± 0.2 6.3 6.3 6.3 36°C
8 rHPIV1-CR84G/Δ170HNT553ALY942A 6.3 ± 0.1 0.3 ± 0.2 0.9 ± 0.6 2.0 ± 0.3 4.9 ± 0.2 5.1 5.1 38°C
9 rHPIV1-CR84G/Δ170HNT553ALΔ1710–11 6.4 ± 0.3 2.6 ± 0.6 4.0 ± 0.4 5.2 5.2 5.2 5.2 35°C
  1. a Data are the mean of three to sixteen experiments.
  2. b Viruses were titrated on LLC-MK2 cells at either permissive (32°C) or potentially restrictive (35°C – 40°C) temperatures for 7 days and virus titers are expressed as the mean ± standard error (S.E.). The limit of detection was 1.2 log10 TCID50/ml.
  3. c Values in bold indicate restricted replication, where the mean log10 reduction in virus titer at the indicated temperature vs 32°C was 2.0 log10 or greater than the difference in titer of HPIV1 wt at the same temperature vs 32°C. A virus is designated ts if restricted replication at 35°C–40°C is observed.
  4. d Underlined values indicate viral shut-off temperature, the lowest temperature at which restricted replication is observed.
  5. e These data have been previously published [13] [15] [16] and are included here for the purposes of comparison.
  6. f The symbol "≥" indicates that virus titers were at the limit of detection and therefore the reduction in virus titer versus 32°C is greater than or equal to the indicated value. There is no S.E. value for viruses at the limit of detection.