Emulsification of the antigen with adjuvant was done using a homogenizer with a standard emulsification stator/rotor connected to an emulsion screen.

The formalin-inactivated ALV405 antigen was formulated into a monovalent vaccine (ALPHA JECT micro®1 PD, PHARMAQ AS, Norway), or into several polyvalent vaccines where find more six components that are heterologous to SAV also were present at a fixed concentration, and where the concentration of ALV405 varied as described below. The six additional components were identical to those found in the commercial injectable oil-based vaccines ALPHA JECT micro®6 (0.05 ml/fish dose) and ALPHA JECT®6-2 (0.1 ml/fish dose) (PHARMAQ AS, Norway). These vaccines contain five bacterial (Aeromonas salmonicida, Listonella anguillarum serotypes 1 and 2, Vibrio salmonicida, Moritella viscosa) and one viral antigen (infectious pancreatic necrosis virus, IPNV). A vaccine was also formulated without any antigen to serve as an adjuvant placebo control. A commercially available vaccine against SAV (Norvax®Compact

PD, MSD Animal Health), was used as reference to the new ALV405-based vaccine in some efficacy studies. Commercial vaccines were always used within the defined expiry date and according to manufacturer recommendations, except that they in lab HSP inhibitor clinical trial trials were removed from the original container and transferred by standard sterile techniques to sterile 50 ml tubes that were blinded to the operator. Three different SAV strains were used either

as vaccine antigen (ALV405) or as challenge strains (ALV407 or ALV413). These strains originated from Atlantic salmon from Norway diagnosed with Pancreas disease. The genotype of these isolates was determined by sequencing of a 1.3 kB cDNA fragment covering the partial open reading frame encoding structural proteins as previously described [7]. All isolates were confirmed to share >99.8% nucleotide identity to the previously Farnesyltransferase reported SAV3 sequence DQ122130. Fish handling, including vaccination, sampling, mortality registration, sample processing and sample analyses was done blinded to the operator. Unvaccinated Atlantic salmon (S. salar L.) were sedated using Metacaine (MS222, PHARMAQ Ltd, UK), tagged for identification and vaccinated by intraperitoneal injection. Vaccination was always performed according to the recommendations of the manufacturer and temperature was set to 12 °C, unless otherwise stated. Tanks were monitored daily for clinical signs of disease or mortalities. In efficacy trials, fish were challenged with a SAV-strain heterologous to the vaccine strain. Fish were starved 24 h prior to challenge. On the day of challenge, the fish were anaesthetized with Metacaine and i.p. injected with 0.1 ml of the challenge strain. No mortality or abnormal behaviour was observed associated with the challenge procedure. Atlantic salmon (n = 80 per group) were tagged by ink tattooing or shortening of adipose fins or maxillae, and vaccinated (mean weight at vaccination: 37.