Huang Zhuhui, Elankumaran Subbiah, Yunus Abdul S, Samal Siba K
Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, 8075 Greenmead Dr., College Park, MD 20742.
J Virol. 2004 Sep;78(18):10054-63. doi: 10.1128/JVI.78.18.10054-10063.2004.
Infectious bursal disease virus (IBDV) causes a highly immunosuppressive disease in chickens. Currently available, live IBDV vaccines can lead to generation of variant viruses. We have developed an alternative vaccine that will not create variant IBDV. By using the reverse genetics approach, we devised a recombinant Newcastle disease virus (NDV) vector from a commonly used vaccine strain LaSota to express the host-protective immunogen VP2 of a variant IBDV strain GLS-5. The gene encoding the VP2 protein of the IBDV was inserted into the most 3'-proximal locus of a full-length NDV cDNA for high-level expression. We successfully recovered the recombinant virus, rLaSota/VP2. The rLaSota/VP2 was genetically stable, at least up to 12 serial passages in chicken embryos, and was shown to express the VP2 protein. The VP2 protein was not incorporated into the virions of recombinant virus. Recombinant rLaSota/VP2 replicated to a titer similar to that of parental NDV strain LaSota in chicken embryos and cell cultures. To assess protective efficacy of the rLaSota/VP2, 2-day-old specific-pathogen-free chickens were vaccinated with the recombinant virus and challenged with a highly virulent NDV strain Texas GB or IBDV variant strain GLS-5 at 3 weeks postvaccination. Vaccination with rLaSota/VP2 generated antibody responses against both NDV and IBDV and provided 90% protection against NDV and IBDV. Booster immunization induced higher levels of antibody responses against both NDV and IBDV and conferred complete protection against both viruses. These results indicate that the recombinant NDV can be used as a vaccine vector for other avian pathogens.
传染性法氏囊病病毒(IBDV)可在鸡群中引发一种具有高度免疫抑制性的疾病。目前可用的IBDV活疫苗会导致变异病毒的产生。我们研发了一种不会产生IBDV变异株的替代疫苗。通过反向遗传学方法,我们从常用疫苗株LaSota设计构建了一种重组新城疫病毒(NDV)载体,用于表达变异IBDV株GLS - 5的宿主保护性免疫原VP2。将编码IBDV的VP2蛋白的基因插入全长NDV cDNA的最3'近端位点以实现高水平表达。我们成功拯救出重组病毒rLaSota/VP2。rLaSota/VP2在遗传上是稳定的,至少在鸡胚中传代12次,并且能够表达VP2蛋白。VP2蛋白未整合到重组病毒的病毒粒子中。重组rLaSota/VP2在鸡胚和细胞培养物中的复制滴度与亲本NDV株LaSota相似。为评估rLaSota/VP2的保护效力,对2日龄无特定病原体鸡接种重组病毒,并在接种后3周用高致病性NDV株Texas GB或IBDV变异株GLS - 5进行攻毒。用rLaSota/VP2接种可产生针对NDV和IBDV的抗体反应,并提供90%的针对NDV和IBDV的保护。加强免疫诱导产生更高水平的针对NDV和IBDV的抗体反应,并对两种病毒提供完全保护。这些结果表明重组NDV可作为其他禽病原体的疫苗载体。