嗜水气单胞菌重庆WL3-X2分离株灭活疫苗对大鲵的免疫保护效果的研究

Immunogenicity and protection effects of a killed Aeromonas hydrophila in giant salamander (Andrias davidianus)

为评估重庆地区分离的嗜气单胞菌WL3-X2分离株对大鲵的免疫原性，本研究将嗜水气单胞菌WL3-X2分离株经福尔马林灭活，作为免疫原，通过腹腔注射途径间隔2周两次免疫健康大鲵，并检测其体内血清抗体、溶菌酶、补体C3及其免疫保护效应。结果显示，免疫嗜水气单胞菌灭活菌能够显著提高大鲵血清抗体滴度、溶菌酶活性和补体C3含量，首免35 d后这3项指标均达到峰值。此外，对初免4周后的大鲵经肌肉注射0.2 mL浓度为1.0×10^8 cfu/mL剂量的嗜水气单胞菌WL3-X2分离株，进行攻毒保护试验。结果表明，免疫组的相对免疫保护率为66.7 %。本研究结果表明，嗜水气单胞菌地方分离株灭活菌对大鲵具有显著免疫保护效力，可以作为大鲵预防嗜水气单胞菌感染的候选疫苗。

To evaluate the immunogenicity of inactivated vaccine against Aeromonas hydrophila, the giant salamanders （Andrias davidianus） were immunized twice via intraperitoneal injection with the vaccine of formalin-killed A.hydrophila WL3-X2 strain isolated from the giant salamander in the Chongqing area, and the agglutinating antibody titers, lysozyme（LZM） activity, complement C3 level in the serum and the protection against the challengeding were examined in the immunized animals. The results showed that the vaccination induced significantly high agglutinating antibody titers, lysozyme （LZM） activity, complement C3 level in content in the immunized giant salamanders, and decreased on 35 day post vaccination, but still significantly higher than that of giant salamander in control group. Moreover, the giant salamanders were challenged with 0.2 mL （108 cfu/mL） of A.hydrophila at 4 weeks post intitial immunization, and the protection rate was 66.7% for the immunized animals. It is thus concluded that the formalin-killed A.hydrophila had a significant protective effect on giant salamander and might be used as effective vaccine against A.hydrophila infection.