Viral haemorrhagic septicaemia (VHS) is an important rhabdo viral disease in the fish farming . Over recent years a highly effective experimental DNA vaccine to VHS has been developed. Virus-induced genes were ultimately retrieved from the subtracted cDNA library, and their differential expression was further confirmed by semi quantitative reverse transcription-PCR and Northern blot analysis. The ability of the plasmid to mediate expression of the viral G-protein on the surface of transfected cells was confirmed by specific immunostaining for the viral protein. The type 1 interferon (IFN) system is a rapid and powerful antiviral defense. Using a luciferase cell line to detect expression of IFN, it was shown that the Common Carp (Cyprinus carpio) Gonad cell line (CCG - p1), produces IFN when transfected with a plasmid encoding the glycoprotein of VHSV, but not with plasmid vector alone.
The results showed that the cells transfected with pcDNA3 vhs-G plasmid were expressing G protein, while the cells transfected with pcDNA3 plasmid did not show any staining. The cells transfected with the pcDNA3 vhs-G showed an increased luciferase activity of 5.4-fold compared with the control non-transfected cells . this increase was statistically significant (p < 0.05).