表达传染性喉气管炎病毒gB基因重组鸡痘病毒疫苗免疫持续期试验

Duration of recombinant fowlpox virus vaccine expressing gB of Infectious laryngotracheitis virus

将200003批疫苗免疫4周龄SPF鸡,免疫后的7、14、21、30、60、90、120、150、180和225d分别采血,分离血清,采用ELISA方法检测血清抗FPV抗体,结果表明重组疫苗免疫后14d,免疫鸡血清抗体已经全部阳转,免疫后的21d血清抗FPV的抗体出现峰值,此后便开始下降,到免疫后的6个月抗体水平已经接近阴性对照的水平。用ILTVWG株和FPV102株强毒进行的攻毒保护试验与血清检测的结果基本一致,在免疫后的5个月内可以使免疫鸡获得100%(10/10)保护,免疫后的6个月对ILT和FP的免疫保护分别为1/7和2/10,此时需要对鸡群实施二次免疫。其他5批疫苗(200001、200002、200101、200102和200103)免疫SPF鸡后5个月用ILTVWG株和FPV102株攻击也获得了完全保护。

Four-week-old SPF chickens were inoculated with fowlpox virus vaccine expressing gB of infectious laryngotracheitis virus (lot 200003). On the day of 7, 14, 21, 30, 60, 90, 120, 150, 180 and 225 post inoculation(PI), blood sample were taken, and the titer of antibody against FPV were detected by ELISA. All of the chickens' antibody were positive at 14th day, and reached peak on 21st day PI, then declined gradually. At the 6th month, it dropped to the negative value. The challenge results of virulent ILTV and FPV is the same as changes of FPV antibody. The vaccine could offer 100% protection in 5 months, but only 1/7 and 2/10 chickens were protected when challenged at the 6th month PI. The vaccine from other five lots had also obtained the same protection results as described.