Fig. 3.

Growth kinetics and IF staining of icPC22A and icPC22A-S1Δ197 in individual virus infection and coinfection conditions in Vero and IPEC-DQ cells. (A, C) 0.01 MOI of the two viruses was used to individually infect or coinfect Vero or IPEC-DQ cell monolayers in 96-well plates. Samples (supernatant and cells) were collected at different time points and the virus titers were detected using the duplex RT-qPCR. (B, D) IF staining of PEDV S proteins of the two viruses in Vero or IPEC-DQ cells (magnification, 200 x). Cells were stained for the detection of icPC22A and icPC22 A-S1Δ197 antigens targeting the S1Δ197 protein (green), and for icPC22A antigens targeting the S1° domain (red), and counterstained for cell nuclei (blue). In the merged images, yellow dots represented icPC22A-infected (or co-infected in coinfection condition) cells and the green dots represented icPC22A-S1Δ197 infection alone. The experimental data were analyzed by Student`s t-test. Letters ‘A, B and C’ indicate a mean significant difference between groups (P < 0.05).