title: [Evaluation the immuno-protective effect of an infectious clone of meq- deleted Marek's disease virus].
abstract: OBJECTIVE
  To evaluate the immuno-protective effect of GX0101 deltameq-BAC containing an infectious meq-null Marek's disease virus genome.
  
  
  METHODS
  One-day-old SPF birds were reared separately in isolators with positive filtered air. On day 1 of age, chickens immunized with 101 microg of GX0101A deltameq-BAC suspended in PBS, challenge infection with 500PFU very virulent rMD5 was performed at day 5 and 12 post-immunization separately. During 90 days after challenge, all bird were recorded and checked for necropsy. The samples of heart and liver were collected for histo-sections.
  
  
  RESULTS
  The protective index of the two vaccines used was 87 and 33 for CVI988/Rispens and GX0101 deltameq-BAC, respectively, after challenged with the very virulent virus rMd5 at day 5 post-immunization. When challenged with rMd5 at day 12 post-immunization, the protection index of GX0101 deltameq-BAC increased to 53%.
  
  
  CONCLUSIONS
  Except that GX0101 deltameq-BAC can confer protection against very virulent Marek's disease virus, a delay in the development of Marek's disease could be observed in some chickens vaccinated with GX0101 deltameq-BAC. On the other hand, compared with CVI988/Rispens, the reconstruction of GX0101 deltameq-BAC in the body is a prerequisite for access to protection. Therefore, there is a blank period after immunization, which provides a chance for infection with the wild Marek's disease virus.
authors.affiliation: The Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China. liyanpeng79@163.com
authors.forename: Yanpeng
authors.initials: Y
authors.lastname: Li
authors.forename: Mengjiao
authors.initials: M
authors.lastname: Kang
authors.forename: Shuai
authors.initials: S
authors.lastname: Su
authors.forename: Jiabo
authors.initials: J
authors.lastname: Ding
authors.forename: Zhizhong
authors.initials: Z
authors.lastname: Cui
authors.forename: Hongfei
authors.initials: H
authors.lastname: Zhu
mesh_terms: D000818:Animals; D002645:Chickens; D004353:Drug Evaluation, Preclinical; D008381:Herpesvirus 2, Gallid / Q000235:genetics / Q000276:immunology* / Q000472:pathogenicity; D008380:Marek Disease / Q000276:immunology* / Q000517:prevention & control* / Q000821:virology; D009856:Oncogene Proteins, Viral / Q000235:genetics* / Q000276:immunology*; D017384:Sequence Deletion; D014765:Viral Vaccines / Q000008:administration & dosage / Q000276:immunology; D014774:Virulence
chemical_list: C100369:Eco-Q protein, Gallid herpesvirus 2; D009856:Oncogene Proteins, Viral; D014765:Viral Vaccines