鳗弧菌三价灭活疫苗的长期免疫保护效果

Long-Term Protection Effect of Vibrio anguillarum Trivalent Inactivated Vaccine

中文关键词: 鳗弧菌疫苗  抗体效价  RPS  抗体持续期  免疫保护期

英文关键词: Vibrio anguillarum vaccine  Serum antibody titer  RPS  Antibodies durability  Immune protection period

中文摘要:

      鳗弧菌(Vibrio anguillarum)是一种能感染多种鱼类的条件致病菌，引起高致死率出血性败血病，流行于我国海水养殖环境，造成极大的经济损失。为此，本研究以鳗弧菌O1、O2和O3血清型菌株为抗原，制备了鳗弧菌三价灭活疫苗，以腹腔注射途径对健康大菱鲆(Scophthalmus maximus) (80.2±4.7) g进行一次免疫，在一次免疫后60 d以同等剂量和途径进行二次免疫。对一免组进行150 d的观测，结果显示，大菱鲆血清的3种抗原的特异抗体水平在免疫后14 d显著升高(P<0.05)，免疫后28 d达到最大值1∶320，免疫后28~150 d稳定在1∶106.7~1∶320，在免疫后14~150 d血清抗体效价均显著高于对照组(P<0.05)；相对免疫保护率(RPS)的检测结果显示，免疫后7 d大菱鲆抵抗鳗弧菌3种血清型病原感染的RPS分别为43.8%、38.9%和16.7%，免疫后28 d RPS均达最大值100%，免疫后28~120 d的RPS值保持在70%~100%，免疫后150 d的RPS值为35%~100%。对二免大菱鲆观测了90 d，二免后3~60 d的大菱鲆血清抗体水平显著高于同期一免的大菱鲆(P<0.05)，二免后60~90 d抗体水平下降，与同期一免鱼无显著差异(P>0.05)；二免大菱鲆的RPS值均高于70%，高于同期一免大菱鲆。上述结果显示，以鳗弧菌三价灭活疫苗一次免疫大菱鲆，抗体持续期不少于150 d，有效免疫保护期(RPS>70%)不少于120 d；二次免疫大菱鲆，抗体持续期和有效免疫保护期(RPS>70%)均不少于150 d。空白组最终体重略高于免疫组，但2组的特定生长率(SGR)无明显差异，说明三价疫苗对大菱鲆生长没有影响。

英文摘要:

      Vibrio anguillarum is a pathogen that can infect a variety of fish and causes highly fatal hemorrhagic septicemia. Its O1, O2, and O3 serotype strains are prevalent in the mariculture environment of China, causing great economic loss. However, the study of polyvalent vaccines of different pathogenic serotypes of V. anguillarum has not been undertaken. For this purpose, a trivalent inactivated vaccine V. anguillarum was made, and its antibody duration and immune protection period were evaluated. The trivalent vaccine was administered to turbot (80.2±4.7 g) at a dose of 108 cells/individual via intraperitoneal injection; booster vaccination was given at 60 days post vaccination (dpv), and the serum antibody titer and RPS of the vaccinated group and control group were compared. Fish vaccinated only once were observed for 150 days, and the results showed that during 14~150 dpv, the antibody level of the vaccinated V. anguillarum group was significantly higher than that in the control group (P<0.05), and rose to 1∶6.7 at 7 dpv, reached peak value at 28 dpv, and during 28~150 dpv hovered between 1∶106.7~1∶320. RPS of three serotype V. anguillarum were 16.7%~43.8% for 7 dpv, then reached 100% at 28 dpv; during 28~120 dpv was 70%~100%, 35%~100% for 150 dpv. The fish vaccinated twice were observed for 90 days; during 3~60 days post-second vaccination (dpsv), their antibody titer was significantly higher (P<0.05) than those vaccinated only once, then went down and was not significantly different (P>0.05) than that of those vaccinated only once. RPS of three serotype V. anguillarum were still higher than 70% and higher than those of fish only vaccinated once. All in all, antibody durability and efficient immune protection period (RPS>70%) of fish vaccinated with V. anguillarum trivalent inactivated vaccine once was longer than 150 days and 120 days respectively, and 150 days for fish that were vaccinated twice. Control group fish reached higher weight in comparison to the vaccinated fish, while SGR between groups for the whole period was not statistically significant (P>0.05).