Transcriptome Profiles Associated to VHSV Infection or DNA Vaccination in Turbot (Scophthalmus maximus)

Abstract

DNA vaccines encoding the viral G glycoprotein show the most successful protection capability against fish rhabdoviruses. Nowadays, the molecular mechanisms underlying the protective response remain still poorly understood. With the aim of shedding light on the protection conferred by the DNA vaccines based in the G glycoprotein of viral haemorrhagic septicaemia virus (VHSV) in turbot (Scophthalmus maximus) we have used a specific microarray highly enriched in antiviral sequences to carry out the transcriptomic study associated to VHSV DNA vaccination/infection. The differential gene expression pattern in response to empty plasmid (pMCV1.4) and DNA vaccine (pMCV1.4-G860) intramuscular administration with regard to non-stimulated turbot was analyzed in head kidney at 8, 24 and 72 hours post-vaccination. Moreover, the effect of VHSV infection one month after immunization was also analyzed in vaccinated and non-vaccinated fish at the same time points. Genes implicated in the Toll-like receptor signalling pathway, IFN inducible/regulatory proteins, numerous sequences implicated in apoptosis and cytotoxic pathways, MHC class I antigens, as well as complement and coagulation cascades among others were analyzed in the different experimental groups. Fish receiving the pMCV1.4-G860 vaccine showed transcriptomic patterns very different to the ones observed in pMCV1.4-injected turbot after 72 h. On the other hand, VHSV challenge in vaccinated and non-vaccinated turbot induced a highly different response at the transcriptome level, indicating a very relevant role of the acquired immunity in vaccinated fish able to alter the typical innate immune response profile observed in non-vaccinated individuals. This exhaustive transcriptome study will serve as a complete overview for a better understanding of the crosstalk between the innate and adaptive immune response in fish after viral infection/vaccination. Moreover, it provides interesting clues about molecules with a potential use as vaccine adjuvants, antiviral treatments or markers for vaccine efficiency monitoring.

Approaches for delaying sexual maturation in salmon and their possible ecological and ethical implications

“…DNA vaccination DNA vaccines are purified bacterial plasmid preparations containing one DNA sequence or more, that express a protein antigen (antigens) or peptides capable of inducing an immune response (Pereiro et al, 2014). The process required for the development of DNA vaccines is relatively simple, which entails that when the process is established, it can be generic for various purposes.…”

“…These effects include development of autoimmunity, host cell genome integration, inflammation of injection site, resistance to antibiotic resistance genes, and tissue destruction (Gillund et al, 2008, Pereiro et al, 2014. Environmental safety aspects include potential shed of the vaccine from the vaccinated fish to the environment or by predatory animals eating the vaccinated fish (Gillund et al, 2008).…”

DNA Vaccines: Regulatory Considerations and Safety Aspects

“…In addition these vaccines may also cause less side-effects than, for example, vaccines based on attenuated pathogens (Pereiro et al, 2014). The process required for the development of DNA vaccines is relatively inexpensive and simple with the advantage that, when fully established, it can be adapted and applied to other systems (Wharen and Liu, 2014).…”

“…Unwanted sideeffects include the development of autoimmunity, host cell genome integration, injection site inflammation, antibiotic resistance due the presence of antibiotic resistance genes within the construct, and tissue destruction due to cytotoxic responses Evensen and Leong, 2013;Gillund et al, 2008;Myhr and Dalmo, 2005;Pereiro et al, 2014). Environmental safety concerns includes the potential of vaccine shedding to the environment and spread via predatory animals (Gillund et al, 2008;Lorenzen and LaPatra, 2005).…”

“…It contains one or more DNA sequences that express a protein antigen (antigens) or peptides capable of inducing immune response (Pereiro et al, 2014), flanked by a eukaryotic promotor/enhancer and a transcription/polyadenylation sequence to promote gene expression in the vaccine recipients. Some of these plasmids also contain an antibiotic resistance gene to be used for selection during the production process.…”