摘要
将共表达传染性支气管炎病毒S1基因和鸡干扰素-γ基因的重组鸡痘病毒(rFPV-IFNγS1)接种4周龄SPF鸡,免疫3周后用异源病毒LSC99I株攻击,考察重组疫苗对异源病毒攻击的保护作用。结果显示,疫苗接种后,免疫鸡血清中很快出现抗体;外周血中CD4+和CD8+T淋巴细胞的百分含量略高于非免疫对照组,但这种差异并不显著。LSC99I株IB病毒攻击后的保护率结果表明,免疫组的发病率为50%(5/10),死亡率为20%(2/10),非免疫对照组的发病率为100%(10/10),死亡率为50%(5/10);另外免疫鸡的病理损伤程度与非免疫对照组相比,二者差异不明显,在排毒时间和排毒量上也没有明显变化。体重分析结果显示,攻毒前免疫组与对照组相比,体重均没有显著变化,但攻毒后免疫组鸡体重增长的幅度要高于非免疫对照组。从以上结果可以说明,重组疫苗虽然能在动物体内很好地表达,但不能对实验动物产生很好的保护作用,而鸡干扰素-γ基因能在动物体内表达并发挥其免疫调节作用,减轻了重组疫苗对体重增长的影响。
Four-week old SPF chickens were inoculated with fowlpox virus vaccine co-expressing gene S1 of infectious bronchitis virus （IBV） and the chicken interferon-γ gene（rFPV-IFNγS1）. SPF chickens were challenged with a heterologous IBV strain LSC99Ⅰ to investigate protective efficacy of the recombinant virus to heterologous virus after three weeks post-inoculation. The results showed that chickens immunized with rFPV-IFNγS1 developed IBV specific antibodies in serum one week after immunization, the ratio of CD^4＋ and CD^8＋T lymphocyte in chicken＇s peripheral blood of immunized group was a little higher than that of the non-vaccinated group, but the difference was inapparent. Morbidity and mortality of immunized group were 50% （5/10） and 20% respectively after challenge with LSC99Ⅰ compared with 100% （10/10） and 50% （5/10） ofnon-vaccinated group, chickens in immunized group had slighter pathological changes when compared to that of non-vaccinated group, but the difference was indistinctive. The length and titer of virus shedding for two groups showed no significant difference. Bodyweight analysis indicated that chickens in both groups showed inapparent weight change before challenge; after challenge, chickens in immunized group had a higher weight gain than chickens in non-vaccinated group. In conclusion, rFPV-IFNγS1 cannot protect chickens against the challenge of heterologous IBV strain LSC99Ⅰ although it can produce IBV-specific antibodies in chickens, chicken IFN-γ is well expressed in vivo and play a role in immunomodulatory which can alleviate the effect of recombinant virus immunization on chicken bodyweight gain.
出处
《畜牧兽医学报》
CAS
CSCD
北大核心
2007年第10期1077-1082,共6页
ACTA VETERINARIA ET ZOOTECHNICA SINICA
