Fig. 4.

Infection of PEDV icPC22A and icPC22A-S1Δ197 in neuraminidase (NA)-treated Vero and IPEC-DQ cells. Vero or IPEC-DQ cell monolayers in 96-well plates were treated with 250 mU NA or mock at 37℃ for 2 h. After three washings with DMEM/RPMI-1640, cells were inoculated with equal amounts of virus at a MOI of 0.02 diluted in the medium containing 10 μg/mL trypsin. After incubation at 37℃ for 2 h, the inoculum was removed followed by three washings. DMEM/RPMI-1640 containing 50 μg/mL soybean trypsin inhibitor (SBTI) and swine PEDV positive serum (virus neutralization titer 1:1024, 1:500 dilution) was added. At 8 hpi, cells were fixed with acetone-methanol (1:4) and infectivity was tested by IF assay. Each Experiment was performed three times. Data are shown as the M ± SD, and number of asterisks indicate significant difference between groups (*, p < 0.05; **, P < 0.01; ***, P < 0.001).