Shenzhen Institute of Guangdong Ocean University, Shenzhen, Guangdong, China; Fisheries College of Guangdong Ocean University, Zhanjiang, Guangdong, China; Guangdong Provincial Engineering Research Center for Aquatic Animal Health Assessment, Shenzhen, Guangdong, China; Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Zhanjiang, Guangdong, China.
Shenzhen Institute of Guangdong Ocean University, Shenzhen, Guangdong, China; Fisheries College of Guangdong Ocean University, Zhanjiang, Guangdong, China; Guangdong Provincial Engineering Research Center for Aquatic Animal Health Assessment, Shenzhen, Guangdong, China.
Fish Shellfish Immunol. 2019 Dec;95:128-139. doi: 10.1016/j.fsi.2019.10.024. Epub 2019 Oct 16.
Fish nocardiosis is a chronic granulomatous bacterial disease mainly caused by three pathogenic bacteria, including Nocardia seriolae, N. asteroids and N. salmonicida. Molecular chaperone DnaK and GroEL were identified to be the common antigens of the three pathogenic Nocardia species in our previous studies. To evaluate the immune protective effect of two DNA vaccines encoding DnaK or GroEL against fish nocardiosis, hybrid snakehead were vaccinated and the immune responses induced by these two vaccines were comparatively analyzed. The results suggested it needed at least 7 d to transport DnaK or GroEL gene from injected muscle to head kidney, spleen and liver and stimulate host's immune system for later protection after immunization by DNA vaccines. Additionally, non-specific immunity parameters (serum lysozyme (LYZ), peroxidase (POD), acid phosphatase (ACP), alkaline phosphatase (AKP) and superoxide dismutase (SOD) activities), specific antibody (IgM) production and immune-related genes (MHCIα, MHCIIα, CD4, CD8α, IL-1β and TNFα) were used to evaluate the immune responses induced in vaccinated hybrid snakehead. It proved that all the above-mentioned immune activities were significantly enhanced after immunization with these two DNA vaccines. The protective efficacy of pcDNA-DnaK and pcDNA-GroEL DNA vaccines, in terms of relative percentage survival (RPS), were 53.01% and 80.71% respectively. It demonstrated that these two DNA vaccines could increase the survival rate of hybrid snakehead against fish nocardiosis, albeit with variations in immunoprotective effects. Taken together, these results indicated that both pcDNA-DnaK and pcDNA-GroEL DNA vaccines could boost the innate, humoral and cellular immune response in hybrid snakehead and show highly protective efficacy against fish nocardiosis, suggesting that DnaK and GroEL were promising vaccine candidates. These findings will promote the development of DNA vaccines against fish nocardiosis in aquaculture.
鱼类诺卡氏菌病是一种慢性肉芽肿性细菌性疾病，主要由三种病原菌引起，包括诺卡氏菌属鱼类亚种、诺卡氏菌属 asteroids 和诺卡氏菌属 salmonicida。在我们之前的研究中，鉴定出分子伴侣 DnaK 和 GroEL 是这三种致病性诺卡氏菌的共同抗原。为了评估两种编码 DnaK 或 GroEL 的 DNA 疫苗对鱼类诺卡氏菌病的免疫保护效果，对杂交乌鳢进行了疫苗接种，并比较分析了这两种疫苗引起的免疫反应。结果表明，DNA 疫苗接种后，DnaK 或 GroEL 基因至少需要 7d 才能从注射肌肉运输到头肾、脾脏和肝脏，并刺激宿主免疫系统进行后期保护。此外，非特异性免疫参数（血清溶菌酶（LYZ）、过氧化物酶（POD）、酸性磷酸酶（ACP）、碱性磷酸酶（AKP）和超氧化物歧化酶（SOD）活性）、特异性抗体（IgM）产生和免疫相关基因（MHCIα、MHCIIα、CD4、CD8α、IL-1β 和 TNFα）用于评估接种杂交乌鳢引起的免疫反应。结果证明，这两种 DNA 疫苗接种后，所有上述免疫活性均显著增强。pcDNA-DnaK 和 pcDNA-GroEL DNA 疫苗的相对存活率（RPS）分别为 53.01%和 80.71%。这表明这两种 DNA 疫苗可以提高杂交乌鳢对鱼类诺卡氏菌病的存活率，但免疫保护效果存在差异。综上所述，这些结果表明，pcDNA-DnaK 和 pcDNA-GroEL DNA 疫苗均可增强杂交乌鳢的固有免疫、体液免疫和细胞免疫反应，并对鱼类诺卡氏菌病具有高度保护效果，提示 DnaK 和 GroEL 是有前途的疫苗候选物。这些发现将促进水产养殖中鱼类诺卡氏菌病 DNA 疫苗的开发。
