Differential immune gene expression profiles in susceptible and resistant full-sibling families of Atlantic salmon (Salmo salar) challenged with infectious pancreatic necrosis virus (IPNV)

• Published in: Developmental & Comparative Immunology
• Main Authors: Reyes-Lopez, Felipe, Romeo, Jose S, Vallejos-Vidal, Eva, Reyes-Cerpa, Sebastian, Sandino, Ana M, Tort, Lluis, MacKenzie, Simon, Imarai, Monica
• Other Authors: Universitat Autonoma de Barcelona, University of Santiago, Institute of Aquaculture, orcid:0000-0003-1845-6826
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2015
• Subjects: IPN-Resistance; Full-sibling families; Salmo salar; Transcriptomics; Microarrays; Immune response; Meier; Atlantic salmon
• Online Access: http://hdl.handle.net/1893/23337; https://doi.org/10.1016/j.dci.2015.06.017; http://dspace.stir.ac.uk/bitstream/1893/23337/1/1-s2.0-S0145305X15001378-main.pdf

This study aims to identify at the expression level the immune-related genes associated with IPN-susceptible and resistant phenotypes in Atlantic salmon full-sibling families. We have analyzed thirty full-sibling families infected by immersion with IPNV and then classified as resistant or susceptible using a multivariate survival analysis based on a gamma-Cox frailty model and the Kaplan–Meier mortality curves. In four families within each group head kidneys were pooled for real-time PCR and one-color salmon-specific oligonucleotide microarray (21K) analysis at day 1 and 5 post-infection. Transcripts involved in innate response (IL-6, IFN-α), antigen presentation (HSP-70, HSP-90, MHC-I), TH1 response (IL-12, IFN-γ, CRFB6), immunosuppression (IL-10, TGF-β1) and leukocyte activation and migration (CCL-19, CD18) showed a differential expression pattern between both phenotypes, except in IL-6. In susceptible families, except for IFN-γ, the expressions dropped to basal values at day 5 post-infection. In resistant families, unlike susceptible families, levels remained high or increased (except for IL-6) at day 5. Transcriptomic analysis showed that both families have a clear differential expression pattern, resulting in a marked down-regulation in immune related genes involved in innate response, complement system, antigen recognition and activation of immune response in IPN-resistant. Down-regulation of genes, mainly related to tissue differentiation and protein degradation metabolism, was also observed in resistant families. We have identified an immune-related gene patterns associated with susceptibility and resistance to IPNV infection of Atlantic salmon. This suggests that a limited immune response is associated with resistant fish phenotype to IPNV challenge while a highly inflammatory but short response is associated with susceptibility.