Transcription of adaptive-immune genes upon challenge with infectious pancreatic necrosis virus (IPNV) in DNA vaccinated rainbow trout

In the present study, rainbow trout weighting 3±0.3 g were vaccinated with an oral DNA vaccine encoding VP2 gene of a prevalent isolate of IPNV in Iranian trout farms encapsulated in sodium alginate microspheres and Chitosan tripolyphosphate (CS/TPP) nanoparticles. The vaccinated fish were then challenged with a virulent isolate of IPNV at 30 days post-vaccination. The transcriptional changes of adaptive- immune genes (IgM and IgT), as well as the VP4 gene of IPNV, as an indicators of viral replication were studied 45 days post-challenge. Analysis of RT-qPCR data showed lower levels of VP4 gene expression in the oral DNA vaccinated trout after IPNV challenge compared with the control one. Moreover, the constructed DNA vaccine did not enhance the expression of IgM and IgT genes above the levels observed in the carrier control group but it showed a mimic of viral activity and contributes to maintaining them at appreciable levels in vaccinated group.