Fig. 1.

(a) Immunofluorescence detection results for the tenth passage (P10) of the cell culture-adapted PDCoV strain CH/XJYN/2016 in infected LLC-PK cells at 0, 12, 24 and 36 h after inoculation (400 ×). PDCoV antigens and nuclei were detected with mouse anti-PDCoV N protein monoclonal antibodies (McAbs) and 4′,6-diamidino-2-phenylindole (DAPI), respectively. LLC-PK cells were fixed and strained with mouse anti-PDCoV N and FITC-goat anti-mouse IgG at 12, 24 and 36 h post-infection (green), nuclei were counterstained with DAPI (blue) ; (b) Electron micrograph of PDCoV virions in cell culture media of infected LLC-PK cells. The arrow indicates the crown-shaped projections on the virus surface; (c) Viral titers of the PDCoV strain CH/XJYN/2016 propagated in LLC-PK cells after serial passage. All the results of a representative experiment performed with triplicate samples are shown.