Furunculosis caused by Aeromonas salmonicida is a major threat to salmonids throughout all their life stages. Vaccination against A. salmonicida has been shown to provide effective protection in aquaculture. The success of many vaccines relies on their association with the appropriate adjuvant to increase their immunogenicity and ensure long‐term protection. In this study, the effects of vaccines using propolis as adjuvants against furunculosis in rainbow trout (Oncorhynchus mykiss) were evaluated. The parameters evaluated included the relative percent survival (RPS), the specific IgM antibody level and the expression profiles of several immune‐related genes in four tissues following immunization and challenge. The results showed that the experimental vaccines containing propolis as adjuvants (ExpVacPro group) could effectively protect the experimental fish against A. salmonicida infection with an RPS of 89.47%. The gene expression data revealed that ExpVacPro could induce the differential expression of the pro‐inflammatory cytokines, MHC class Ⅰ, T‐cell markers and Ig markers in immunized fish, with higher levels in liver and spleen than in head kidney and gill. ExpVacPro initially increased the expression of MHC I and IL8 genes in related pathways, and then gradually increased the expression of IL‐1β and IgT genes for about 2 weeks. During the post‐vaccination challenge, the expression levels of all detected genes were up‐regulated especially for CD8 and IgT genes. The specific IgM antibody titres were significantly induced following immunization and challenge. In conclusion, the results indicated that propolis could improve potency and efficacy of formalin‐inactivated A. salmonicida vaccine as adjuvants.

中文翻译：

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蜂胶对福尔马林灭活的鲑鱼气单胞菌疫苗免疫增强的影响

鲑鱼气单胞菌引起的糠un病是鲑鱼整个生命周期的主要威胁。已证明针对鲑鱼曲霉的疫苗接种可在水产养殖中提供有效的保护。许多疫苗的成功取决于它们与适当佐剂的结合，以提高其免疫原性并确保长期保护。在这项研究中，使用蜂胶作为佐剂的疫苗对虹鳟鱼的真菌病的效果（Oncorhynchus mykiss）进行了评估。评估的参数包括相对存活率（RPS），特异性IgM抗体水平以及免疫和激发后四个组织中几个免疫相关基因的表达谱。结果表明，含有蜂胶作为佐剂的实验疫苗（ExpVacPro组）可以有效保护实验鱼类免受沙门氏菌的感染，RPS为89.47％。基因表达数据表明，ExpVacPro可以诱导免疫鱼中促炎细胞因子，MHCⅠ类，T细胞标志物和Ig标志物的差异表达，肝脏和脾脏中的水平高于头肾和腮中的水平。ExpVacPro最初会增加MHC I和IL8的表达相关通路中的IL-1β和IgT基因的表达，然后持续约2周的时间逐渐增加。在接种疫苗后的攻击中，所有检测到的基因的表达水平均上调，尤其是对于CD8和IgT基因。免疫和激发后，特异性IgM抗体滴度得到明显诱导。总之，结果表明蜂胶可以提高福尔马林灭活的沙门氏菌疫苗作为佐剂的效力和功效。