Quantitation of immune response gene expression and cellular localisation of interleukin-1s mRNA in Atlantic salmon, Salmo salar L., affected by amoebic gill disease (AGD)

• Published in: Veterinary Immunology and Immunopathology
• Main Authors: Bridle, AR, Morrison, RN, Cupit Cunningham, PM, Nowak, BF
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier BV 2006
• Subjects: Agricultural and Veterinary Sciences; Fisheries Sciences; Aquaculture; Atlantic salmon; Salmo salar
• Online Access: https://doi.org/10.1016/j.vetimm.2006.08.002; http://www.ncbi.nlm.nih.gov/pubmed/16956669; http://ecite.utas.edu.au/40491

The characterisation of selected immune response genes during amoebic gill disease (AGD) in Atlantic salmon, Salmo salar L., was performed using semi-quantitative RT-PCR, quantitative real-time RT-PCR (qRT-PCR), and in situ hybridisation (ISH). The immune response genes of interest were interleukin-1 (IL-1), inducible nitric oxide synthase (iNOS), serum amyloid A (SAA), and serum amyloid P-like pentraxin (SAP). Atlantic salmon were inoculated with the ectoparasite Neoparamoeba sp., the causative agent of AGD, and gill, liver and anterior kidney tissue sampled at 0, 7 and 14 d post-inoculation (p.i.). Semi-quantitative RT-PCR was performed on the tissue samples to identify up/down-regulated mRNA expression relative to uninfected control fish and normalised to the housekeeping gene, -actin. Interleukin-1 (IL-1) was the only immune response gene of those investigated whose mRNA was differentially regulated in any of the tissues and was found to be up-regulated in the gills by semi-quantitative RT-PCR. Increased gill IL-1 mRNA expression was then accurately quantitated and confirmed using probe-based qRT-PCR. The cellular localisation of the IL-1 mRNA expression in the gills of uninfected and infected fish was then determined by ISH using an IL-1-specific biotinylated cRNA probe. Expression of IL-1 mRNA was localised to filament and lamellar epithelium pavement cells in gills of uninfected and infected Atlantic salmon. These data implicate the involvement of IL-1 at the site of infection, the gills, of Atlantic salmon during AGD. This work supports previous studies that suggest IL-1 is important in the regulation of the fish immune response to parasitic infection but additionally shows the cellular localisation of fish IL-1 mRNA expression during infection. 2006 Elsevier B.V. All rights reserved.