Genomic and Virulence Investigations of a Novel Porcine Deltacoronavirus Strain Identified in South Korea

Figure 2

Dependency of PDCoV strains on cell surface acids for infection. (a) Neuraminidase treatment infectivity assay. ST or IPEC-J2 cells were pretreated with neuraminidase (NA+) or PBS (NA−) at 37°C for 2 hr and then inoculated with KNU-1607 or GNU-2105 at an MOI of 1 for 1 hr in the presence of trypsin. Cells were maintained in α-MEM or RPMI containing 5% FBS and subjected to IFA at 5 hpi as described in the legend of Figure 1(a). The percentage of fluorescent foci of sialic acid-dependent infection was calculated by counting the infected cells in 200× microscopic fields. IFA images acquired with a fluorescence microscope are presented at the bottom. (b) Fluorescence intensity measurement. The fluorescence emission of the IFA staining, as described above, in the wells was detected by fluorometry, and the percentage of fluorescent intensity was plotted. The values shown are the mean of three independent experiments, and the error bars denote the SDM. .

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