Search

The Gram-negative bacterium A. salmonicida is the causal agent of furunculosis and used to be one of the most loss-causing bacterial infections in the salmonid aquaculture industry with a mortality rate of about 90% until the 1990s, when an inactivated vaccine with mineral oil as adjuvant was successfully implemented to control the disease. However, the use of this vaccine is associated with inflammatory side effects in the peritoneal cavity as well as autoimmune reactions in Atlantic salmon, and incomplete protection has been reported in rainbow trout. We here aimed at developing and testing a recombinant alternative vaccine based on virus-like particles (VLPs) decorated with VapA, the key structural surface protein in the outer A-layer of A. salmonicida. The VLP carrier was based on either the capsid protein of a fish nodavirus, namely red grouper nervous necrotic virus (RGNNV) or the capsid protein of Acinetobacter phage AP205. The VapA and capsid proteins were expressed individually in E. coli and VapA was fused to auto-assembled VLPs using the SpyTag/SpyCatcher technology. Rainbow trout were vaccinated/immunized with the VapA-VLP vaccines by intraperitoneal injection and were challenged with A. salmonicida 7 weeks later. The VLP vaccines provided protection comparable to that of a bacterin-based vaccine and antibody response analysis demonstrated that vaccinated fish mounted a strong VapA-specific antibody response. To our knowledge, this is the first demonstration of the potential use of antigen-decorated VLPs for vaccination against a bacterial disease in salmonids.

Supplemental materialsCurrent and future burdens of heat-related hyponatremia - a nationwide register-based study

Additional file 1: Table S1. Allocation of the fish at the start of the experiment. Table S2. Analysis of the composition of the β-glucan used in this study. Figure S3. Principal component analysis showing the microbiota of the fish at week 6. Figure S4. Heatmap showing the 10 most abundant bacterial phyla in the intestine of the fish for the two control groups and the groups receiving the three different concentration of β-glucan. Table S5. Performance of the fish over the course of the experiment. Figure S6. Average weight of the fish per treatment over the course of the experiment. Figure S7. Average Fulton's condition factor (K) of the fish per treatment over the course of the experiment. Table S8. All metabolites measured in the serum of the fish for all investigated groups. Table S9. Metabolites measured at significantly different levels between treated fish and the control. Arrows indicate if the metabolite were upregulated (↑) or downregulated (↓) relative to the control without β-glucan treatment. Lack of significant change is indicated by “No”. Figure S10. Survival curves of the fish following 9 h bath exposure to 1.6 × 107 CFU∙mL−1 of live Y. ruckeri O1 biotype 2 (100415-1/4).

Supplemental data:Limited Genetic Overlap Between Hashimoto's thyroiditis and Graves' disease in Twins: A Population-based Study.The Journal of Clinical Endocrinology and Metabolism

Supplemental data:Limited Genetic Overlap Between Hashimoto's thyroiditis and Graves' disease in Twins: A Population-based Study.The Journal of Clinical Endocrinology and Metabolism

Supplemental materials for manuscript: Sex-specific risk of cardiovascular disease in autoimmune Addison’s disease – a population-based cohort study.

Cost-effectiveness of tolvaptan for the treatment of hyponatraemia secondary to SIADH in Sweden. (DOCX 468Â kb)

Immunostimulants offered to fish in feed are considered to confer protection against various bacterial diseasesbut the effects on the antiparasitic response are largely unknown. Therefore effects of dietary β-1,3-glucan on innateimmune parameters of juvenile rainbow trout Oncorhynchus mykiss and on susceptibility to the skin-parasitic ciliateIchthyophthirius multifiliis (Ich) have been investigated. A basal diet (dry pelleted feed) was supplemented with0% (control), 0.2% (low), 2.0% (medium), and 5.0% (high) of the β-1,3-glucan particulate insoluble algae glucan,paramylon, from Euglena gracilis. Fish (total 440) were divided into four groups each with 110 fish (kept in duplicatetanks of 55) and each diet was fed to two replicate groups at a daily feeding rate of 1.5% of fish biomass for 56consecutive days. Liver and plasma sampling was performed at day 0 and after feeding with β-1,3-glucans for 14,28, 42, and 56 days and subsamples of fish were exposed to Ich at day 14 and 45. Gene expression in trout liverwas investigated by real-time qPCR and genes encoding immune molecules including acute phase proteins (SAA,hepcidin, and precerebellin), immunoglobulins (IgM and IgT), cytokine (IL-1β), and lysozyme were investigated. Inaddition plasma lysozyme activity was recorded. At the start of the experiment the 5.0% glucan supplemented fishbecame more infected by parasites compared to control fish (0.0%) but after 45 days feeding they obtained significantlyfewer trophonts. Plasma lysozyme activity of fish fed low (0.2%) and medium (2.0%) glucan supplementationfluctuated, while high (5.0%) glucan was associated with an elevation of lysozyme activity. Plasma lysozyme activitywas positively correlated to expression of the lysozyme gene and to body mass of fish. Groups fed low (0.2%) andmedium (2%) glucan diets showed a trend for down-regulation of immune relevant genes whereas the group fed withhigh (5%) glucan showed a trend for up-regulation of genes especially the acute phase reactant SAA.