维氏气单胞菌弱毒株FS12001及其疫苗对异育银鲫的免疫效果

Immune effect of Aeromonas veronii vaccines prepared with a low pathogenic strain FS12001 to Carassius auratus gibelio

  • 摘要: 为探究由维氏气单胞菌 (Av)弱毒株FS12001制备的疫苗免疫效果,将Av弱毒株FS12001制备活疫苗、灭活疫苗、ISA763A-灭活疫苗和蜂胶-灭活疫苗,腹腔注射免疫异育银鲫,同时设ISA763A佐剂、蜂胶佐剂及0.65% NaCl作为对照组。于免疫后1、3、5、7和 14 d经实时荧光定量 PCR (qRT-PCR)检测脾脏组织中 IgMIL-1βLZM 的基因表达量;于免疫后 7、14、21、28、42和 48 d尾静脉采血分离血清,检测IgM抗体水平,测定SOD和LZM酶活性;于免疫28 d 后用2株Av强毒株分别攻毒各组实验鱼,连续观察记录7 d,计算各免疫组的相对保护率。结果显示,各免疫组脾脏组织中IgMIL-1βLZM的基因表达量高于对照组,且ISA763A-灭活疫苗组和蜂胶-灭活疫苗组的表达量显著高于其他各实验组。各疫苗免疫组血清特异性抗体水平均显著高于0.65% NaCl对照组和佐剂对照组。各疫苗免疫组的LZM活性均在28 d最高,灭活疫苗组、ISA763A-灭活疫苗组及蜂胶-灭活疫苗组SOD活性均在7 d 最高。菌株AVCA07攻毒后,活疫苗组、灭活疫苗组、ISA763A-灭活疫苗组和蜂胶-灭活疫苗组的 RPS 分别为 63%、56%、100% 和 56%;菌株YC170511攻毒后,以上4个免疫组RPS分别为59%、55%、93% 和 72%。研究表明,用弱毒株FS12001制备疫苗,注射免疫异育银鲫后均可增加脾脏中 IgMIL-1βLZM 的基因表达量,提高血清抗体水平,增强SOD和LZM酶活性,增强其抵抗Av感染的能力。

     

    Abstract: Aeromonas veronii can infect a variety of aquatic and terrestrial animals and cause motile aeromonad septicemia (MAS).To explore the immune effect of the vaccine prepared with A. veronii low pathogenic strain FS12001, Carassius auratus gibelio were immunized with live vaccine, inactivated vaccine, ISA763A-inactivated vaccine and propolis-inactivated vaccine prepared with FS12001 through intraperitoneal injection, with ISA763A- 0.65% NaCl, propolis- 0.65% NaCl and 0.65% NaCl used as controls. The gene expressions of IgM, IL-1β and LZM were detected by real-time quantitative PCR (qRT-PCR) in spleen tissues at 1, 3, 5, 7 and 14 d post immunization (dpi). Sera were collected from the tail vein at 7, 14, 21, 28, 42 and 48 dpi. The specific antibody IgM levels were detected through indirect ELISA. SOD activity and LZM activity were measured. The experimental groups were challenged with two A.veronii virulent strains at 28 dpi, and the relative percent survival (RPS) was calculated. The gene expressions of IgM, IL-1β and LZM in spleen tissues of each immunized group were higher than those of the 0.65% NaCl control, and the expressions of ISA763A-inactivated vaccine group and propolis-inactivated vaccine group were significantly higher than those of all other groups. The serum-specific antibody levels of each vaccine-immunized group were significantly higher than those of the 0.65% NaCl and adjuvant controls. LZM activity values were highest at 28 dpi in all vaccine-immunized groups, and SOD activity values were the highest at 7 dpi in the inactivated vaccine group, ISA763A-inactivated vaccine group and propolis-inactivated vaccine group. The RPSs of live vaccine group, inactivated vaccine group, ISA763A-inactivated vaccine group and propolis-inactivated vaccine group challenged with AVCA07 were 63%, 56%, 100% and 56%, respectively, and the RPSs of these immune groups challenged with YC170511 were 59%, 55%, 93% and 72%, respectively. This study shows that the several vaccines prepared with A.veronii FS12001 can increase the gene expressions of IgM, IL-1β and LZM, serum specific antibody level, SOD activity and LZM activity, and enhance the ability of C. auratus gibelio to resist A.veronii infection. This study can provide the basis for A.veronii vaccines and prevention and control of MAS.

     

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