Citation Skinner LA, LaPatra SE, Adams A, Thompson K, Balfry SK, McKinley RS & Schulte PM (2010) Supra-physiological levels of cortisol suppress lysozyme but not the antibody response in Atlantic salmon, Salmo salar L., following vaccine injection. Aquaculture, 300 (1-4), pp. 223-230. https://doi.org/10.1016/j.aquaculture.2010.01.002
Abstract Using key immunological parameters including lysozyme activity and specific antibody titres, we examined the influence of chronic, supra-physiological levels of cortisol on the vaccine-induced immune responses of farmed Atlantic salmon, Salmo salar L. Individual fish were injected with a polyvalent, oil-adjuvanted bacterial vaccine 400 degree days prior to sea water entry, and subsequently injected with a cortisol implant at either 53 or 212 degree days post-vaccine injection. All fish were sampled 74 degree days post-cortisol injection (at 127 and 286 degree days post-vaccine injection). Separate groups of Atlantic salmon were injected with a DNA vaccine against infectious haematopoietic necrosis virus (IHNV) either by itself or concurrently with the polyvalent, oil-adjuvanted bacterial vaccine and treated as described above. Because we were unable to detect a significant increase in lysozyme activity as a result of the DNA vaccine, we cannot determine whether there was a cortisol-induced suppression of this innate immune response. Our results indicate, however, that if Atlantic salmon are exposed to significant elevations in plasma cortisol following the injection of a polyvalent, oil-adjuvanted bacterial vaccine alone or concurrently with the IHNV DNA vaccine, lysozyme activity is suppressed while induction of pathogen-specific antibody titres is unchanged. We conclude, therefore, that chronically elevated, supra-physiological levels of plasma cortisol suppress the lysozyme-mediated innate immune response in Atlantic salmon injected with a polyvalent, oil-adjuvanted bacterial vaccine, but do not affect antibody production associated with the adaptive immune response.