腺胃病变型鸡传染性支气管炎病毒(IBV-D971株)致弱的研究

Development of an Attenuated Proventriculus-type Avian Infectious Bronchitis Virus

将IBV_D971株病毒在SPF鸡胚上连续传至 12 0代 ,培育出了一株毒力明显减弱 ,并且具有良好免疫原性的腺胃病变型鸡传染性支气管炎病毒弱毒株 (IBV_D971株 )。IBV_D971F10 5代毒力明显下降 ,以 10 9.2 5EID50 接种 1日龄SPF鸡 5 / 5无不良反应。IBV_D971F10 5代毒连续通过 1日龄SPF鸡体 5代 ,未见毒力返强。以 10 3EID50 免疫 1日龄SPF鸡 ,攻毒后 5 / 5保护 ,对照 5 /

Avian infectious bronchitis virus(IBV)D971 strain (IBV_D971) causing proventricular disease was attenuated and retained its immunogenicity after 120 passages in SPF chicken embryos.The embryo_adapted virus was shown to have no pathogenicity to 1_day_old SPF chickens as indicated by inoculating with 10 8.25 EID 50 of the 105th passage of IBV_D971.The 105th passage of IBV_D971 didn′t revert to virulence after 5 passages in 1_day_old SPF chickens.100%(5/5) of the chickens inoculated with 10 3 EID 50 of the attenuated virus were protected from virulent challenge.However,100%(5/5)non_inoculated controls got diseased when challenged.