Fig. 1

Adaption of PD-H in Colo320 and functional analysis of PD-SK. (A) Susceptibility of Colo320 cells to PD-H. Colo320 and HeLa cells were infected as indicated with of PD-H. Cell viability was determined 24 h and 48 h post infection by crystal violet staining. (B) Development of viral titers during serial passaging of PD-H. Colo320 cells were infected with MOI 0.1 and incubated for 72 h. Viral titer was determined by plaque assay. The procedure was repeated for 10 passages. Shown are mean values ± SEM. Significance compared to previous passage, * p < 0.05; ** p < 0.01. (C) Changes of cell viability during passaging of PD-H. Colo320 cells were infected with PD-H, PD-5 or PD-10 at the indicated MOIs. Cell viability was measured by XTT assay 72 h after infection. Shown are mean values ± SEM. Significance, ** p < 0.01; **** p < 0.0001. (D) Detection of mutations in PD-5 and PD-10. Upper panel, Chromatograms of the sanger sequencing of viral RNA isolated from PD-H, PD-5 and PD-10. Nucleotide substitutions are highlighted in yellow boxes. Lower panel, schematic of PD-H genomic RNA, location of the nucleotide and resulted aa substitutions detected in PD-10. (E) Comparison of aa substitutions found in PD-10 with other CVB3 strains. (F) Virus growth kinetics. Colo320 cells were infected with PD-H, PD-10 and PD-SK at MOI 0.1. Virus titer was determined by plaque assay. Shown are mean values ± SEM. Significance compared to PD-H, * p < 0.05; **** p < 0.0001. (G) Cell viability. Colo320 cells were infected with PD-H, PD-10 or PD-SK at the indicated MOI. Cell viability was measured 48 h after infection. Shown are mean values ± SEM. Significance, ** p < 0.01; *** p < 0.001; **** p < 0.0001