Hong et al (5) reported that the cytopathic effect (CPE) showed by cells infected with IPNV is a post apoptotic process, related to the suppression of the gene of the survival factor Mcl-1, a member of the antiapoptotic protein family Bcl-2; in contrast, Espinoza et al (13), reported that only 12% of the cell population infected with a strain of serotype VR-299 showed apoptosis, with cell death by necrosis taking precedence.
Chinook salmon embryo (CHSE-214) cells were used for the propagation of IPNV and in assays to assess apoptosis.
The gene fragments of 1180 and 450 pb, corresponding to the VP2 and VP5 proteins of IPNV, were detected by RT-PCR in cells infected with the three strains (not shown).
The analysis of the VP2 sequence shows that the residues involved in the virulence or infectivity of the IPNV in the V70/06 strain corresponded to Pro-217 and Ala-221; Ala-217 and Thr-221 for V112/06, and finally Pro-217 and Thr-221 for V33/98 (Table 1).
The IPNV diagnosis used cell culture on Chinook salmon embryo cell lines in plates containing 24 wells (7).
FRS scientists have been testing for IPNV since the 1970s (18); standard methods approved by the Office International des Epizooties (7) were used through the 1990s.
Data available for 1996-2001 have been used to find underlying patterns in the distribution of prevalence of IPNV in Scottish salmon farms.