鸡传染性支气管炎耐热活疫苗的研究

Study on Thermo-tolerant Living Vaccine of Avian Infectious Bronchitis

应用鸡传染性支气管炎病毒(H52株)与不同耐热保护剂配方和冻干曲线进行筛选。结果表明:采用冻干曲线2和耐热保护剂WXS冻干鸡传染性支气管炎病毒H52弱毒疫苗效果最佳。试制耐热活疫苗3批,其各项检验均符合要求。耐老化试验表明:经过37℃放置10d的每羽份病毒含量下降0.6～0.8个滴度,每羽份病毒含量达104.7～105.1EID50。保存期试验表明:2～8℃保存24个月疫苗每羽份病毒含量下降0.4～0.6个滴度,每羽份病毒达104.1～104.3EID50。疫苗2～8℃保存24个月后效检抗体水平达到1∶16～1∶32。免疫持续期试验表明:免疫21日龄SPF鸡,6个月后血清中和抗体效价达到1∶32～1∶64。田间试验表明临床观察无不良反应,安全有效。特异性试验表明耐热活疫苗抗原性不变。耐热保护剂生物学和理化特性表明保护剂安全、稳定,室温保存期达3个月。

Avian infectious bronchitis virus （IBV） attenuated strain （H52）was selected by freeze-drying experiments blending with different suspending media and lyophilization curves. The IBV attenuated strain （H52） choosed by WXS and lyophilization curve 2 was most favorable. Three batches of thermo-tolerant living vaccine of IBV（H52）produced by WXS and lyophilization curve 2 were tested eligible. The heat-resisting test showed that the titer of virus reduced 0.6 to 0.8 EID50 per dose after storing at 37 ℃ for 10 days and still remained 10^47 to 10^51 EID50 per dose. The experiment of the preserver period reflected that the titer of virus reduced 0.4 to 0.6 EID50 per dose after storing at 4 ℃ for 24 months and still remained 10^41 to 10^43 EID50 per dose. The titer of neutralization sera antibody remained 1：16 to 1：32 after storing at 2 to 8 ℃ for 24 months. The immunity lasting test indicated that immunizing SPF chickens at 21 days age,the titer of neutralization sera antibody reached 1：32 to 1：64 after 6 months. The field test showed that thermo-tolerant living vaccine of IBV （H52） was safe and effective. The specificity test showed that infectious bronchitis standard positive serum can Specially identify it. The biological characters and physical ＆ chemical characters revealed the thermo-tolerant stabilizer was safe and stable, and could be stored at room temperature for three months.