3.2. PDCoV replicated in PK-15 while Vero cells did not allow
PDCoV propagation
Following PDCoV detection, our objective was to isolate in vitrousing PK-15 and Vero cell lines. Despite the high viral load detected by
PCR, we did not see evidence of cytopathic effect during the first 5
days following inoculation in any of the cell line tested. Thus, we
performed a second blind passage to evidence viral replication.
Interestingly, 48 h post inoculation, cytopathic effect was observed in
PK-15 cell line, but morphological changes in Vero cell line were
absent. These findings were also confirmed by qRT-PCR. Within the major
cellular changes observed are: pyknosis, cell rounding, monolayer
disruption, cell detachment, which correspond to typical coronavirus
cytopathic effect previously described (see Figure 1A). Furthermore, the
immunofluorescence test in PK-15 infected cells, confirmed the presence
of PDCoV (see Figure 1B). Following isolation, a sample was selected and
prepared for genome sequencing.