Table 2.
Differential Cell Line Susceptibility to Human Betacoronavirus 2c EMC/2012, as Defined by Viral Load, on Days 1, 3, and 5 After Infection
| Viral Load, log10 copies/mL, mean ± SDa,b |
|||||||
|---|---|---|---|---|---|---|---|
| Cell Line | Day 0 | Day 1 | P | Day 3 | P | Day 5 | P |
| Human | |||||||
| Respiratory tract | |||||||
| Hep-2 | 5.87 ± 0.10 | 5.84 ± 0.04 | .784 | 5.85 ± 0.02 | .823 | 5.85 ± 0.10 | .859 |
| A549 | 5.90 ± 0.16 | 6.97 ± 0.11 | .025 | 7.18 ± 0.04 | .050 | 7.45 ± 0.31 | .045 |
| Calu-3 | 5.62 ± 0.04 | 9.63 ± 0.04 | <.001 | 10.42 ± 0.22 | .016 | 10.25 ± 0.06 | .001 |
| HFL | 5.72 ± 0.02 | 9.54 ± 0.35 | .041 | 10.73 ± 0.03 | .002 | 10.45 ± 0.04 | .003 |
| Gastrointestinal tract | |||||||
| Caco-2 | 5.82 ± 0.04 | 10.19 ± 0.61 | .060 | 10.49 ± 0.17 | .009 | 10.26 ± 0.16 | .018 |
| Liver | |||||||
| Huh-7 | 5.87 ± 0.07 | 10.47 ± 0.22 | .011 | 9.56 ± 0.11 | .002 | 9.63 ± 0.02 | .006 |
| Genitourinary tract | |||||||
| HeLa | 5.75 ± 0.06 | 5.94 ± 0.08 | .124 | 5.86 ± 0.17 | .522 | 5.99 ± 0.08 | .079 |
| HEK | 5.82 ± 0.05 | 10.45 ± 0.25 | .015 | 9.97 ± 0.17 | .012 | 9.90 ± 0.03 | .001 |
| Neuromuscular cells | |||||||
| NT2 | 5.72 ± 0.04 | 7.83 ± 0.02 | .002 | 8.22 ± 0.04 | <.001 | 8.40 ± 0.14 | .015 |
| RD | 5.66 ± 0.04 | 6.68 ± 0.24 | .098 | 6.90 ± 0.02 | .003 | 6.78 ± 0.01 | .013 |
| Immune cells | |||||||
| THP-1 | 6.75 ± 0.01 | 7.03 ± 0.02 | .020 | 7.28 ± 0.06 | .044 | 7.40 ± 0.06 | .036 |
| U937 | 6.70 ± 0.06 | 7.10 ± 0.07 | .028 | 7.19 ± 0.04 | .016 | 7.25 ± 0.07 | .015 |
| Raji | 6.71 ± 0.05 | 6.85 ± 0.02 | .106 | 6.76 ± 0.08 | .528 | 7.05 ± 0.04 | .019 |
| H9 | 6.52 ± 0.03 | 6.55 ± 0.57 | .592 | 6.73 ± 0.04 | .038 | 6.71 ± 0.03 | .020 |
| His-1 | 5.55 ± 0.04 | 9.44 ± 0.08 | .001 | 9.27 ± 0.05 | <.001 | 9.12 ± 0.01 | .004 |
| Nonhuman | |||||||
| Mammals | |||||||
| LLC-MK2 | 5.94 ± 0.04 | 10.73 ± 0.20 | .017 | 10.61 ± 0.10 | .009 | 10.34 ± 0.05 | .001 |
| Vero | 5.73 ± 0.04 | 9.61 ± 0.57 | .064 | 10.15 ± 0.36 | .034 | 10.93 ± 0.18 | .014 |
| Vero-E6 | 5.57 ± 0.08 | 9.34 ± 0.12 | .002 | 10.79 ± 0.09 | .002 | 10.55 ± 0.04 | <.001 |
| MDCK | 5.65 ± 0.04 | 5.78 ± 0.21 | .522 | 5.65 ± 0.00 | .772 | 5.72 ± 0.01 | .190 |
| CRFK | 5.43 ± 0.08 | 5.91 ± 0.01 | .072 | 5.85 ± 0.07 | .035 | 5.79 ± 0.03 | .080 |
| PK-15 | 5.39 ± 0.06 | 8.30 ± 0.10 | .003 | 10.16 ± 0.30 | .025 | 10.12 ± 0.08 | <.001 |
| RK-13 | 5.37 ± 0.05 | 6.12 ± 0.08 | .013 | 7.40 ± 0.05 | .036 | 7.75 ± 0.02 | .003 |
| CL-1 | 5.56 ± 0.05 | 7.17 ± 0.01 | .008 | 7.52 ± 0.03 | .001 | 8.19 ± 0.86 | .144 |
| 3T3 | 5.40 ± 0.01 | 5.47 ± 0.15 | .669 | 5.18 ± 0.03 | .044 | 5.22 ± 0.10 | .229 |
| RK3E | 5.31 ± 0.07 | 5.40 ± 0.05 | .302 | 5.34 ± 0.02 | .639 | 5.24 ± 0.01 | .443 |
| RMC | 5.29 ± 0.08 | 5.80 ± 0.21 | .154 | 5.32 ± 0.07 | .713 | 5.36 ± 0.09 | .516 |
| Chicken | |||||||
| DF-1 | 5.92 ± 0.02 | 6.32 ± 0.14 | .115 | 6.24 ± 0.04 | .041 | 6.20 ± 0.00 | .011 |
| Insect | |||||||
| C6-36 | 5.93 ± 0.01 | 6.50 ± 0.06 | .049 | 6.37 ± 0.11 | .110 | 6.36 ± 0.11 | .111 |
a All experiments were done in duplicate. The mean viral loads on days 1, 3, and 5 were compared with the mean baseline viral load on day 0.
b No significant difference in mean viral load was noted in monolayer cell lines after additional inoculation in serum-free medium supplemented with tosyl phenylalanyl chloromethyl ketone–treated trypsin (2 µg/mL).