title: Avirulent Marek's disease virus type 1 strain 814 vectored vaccine expressing avian influenza (AI) virus H5 haemagglutinin induced better protection than turkey herpesvirus vectored AI vaccine.
abstract: BACKGROUND
  Herpesvirus of turkey (HVT) as a vector to express the haemagglutinin (HA) of avian influenza virus (AIV) H5 was developed and its protection against lethal Marek's disease virus (MDV) and highly pathogenic AIV (HPAIV) challenges was evaluated previously. It is well-known that avirulemt MDV type 1 vaccines are more effective than HVT in prevention of lethal MDV infection. To further increase protective efficacy against HPAIV and lethal MDV, a recombinant MDV type 1 strain 814 was developed to express HA gene of HPAIV H5N1.
  
  
  RESULTS
  A recombinant MDV-1 strain 814 expressing HA gene of HPAIV H5N1 virus A/goose/Guangdong/3/96 at the US2 site (rMDV-HA) was developed under the control of a human CMV immediate-early promoter. The HA expression in the rMDV-HA was tested by immunofluorescence and Western blot analyses, and in vitro and in vivo growth properties of rMDV-HA were also analyzed. Furthermore, we evaluated and compared the protective immunity of rMDV-HA and previously constructed rHVT-HA against HPAIV and lethal MDV. Vaccination of chickens with rMDV-HA induced 80% protection against HPAIV, which was better than the protection rate by rHVT-HA (66.7%). In the animal study with MDV challenge, chickens immunized with rMDV-HA were completely protected against virulent MDV strain J-1 whereas rHVT-HA only induced 80% protection with the same challenge dose.
  
  
  CONCLUSIONS
  The rMDV-HA vaccine was more effective than rHVT-HA vaccine for protection against lethal MDV and HPAIV challenges. Therefore, avirulent MDV type 1 vaccine is a better vector than HVT for development of a recombinant live virus vaccine against virulent MDV and HPAIV in poultry.
authors.affiliation: Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, China.
authors.forename: Hongyu
authors.initials: H
authors.lastname: Cui
authors.forename: Hongbo
authors.initials: H
authors.lastname: Gao
authors.forename: Xianlan
authors.initials: X
authors.lastname: Cui
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhao
authors.forename: Xingming
authors.initials: X
authors.lastname: Shi
authors.forename: Qiaoling
authors.initials: Q
authors.lastname: Li
authors.forename: Shuai
authors.initials: S
authors.lastname: Yan
authors.forename: Ming
authors.initials: M
authors.lastname: Gao
authors.forename: Mei
authors.initials: M
authors.lastname: Wang
authors.forename: Changjun
authors.initials: C
authors.lastname: Liu
authors.forename: Yunfeng
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000818:Animals; D001717:Birds; D002642:Chick Embryo; D002645:Chickens; D019084:Fluorescent Antibody Technique, Indirect; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000276:immunology*; D026002:Herpesvirus 1, Meleagrid; D008381:Herpesvirus 2, Gallid; D053124:Influenza A Virus, H5N1 Subtype; D008380:Marek Disease / Q000517:prevention & control*; D008856:Microscopy, Fluorescence; D016366:Open Reading Frames; D011401:Promoter Regions, Genetic; D011994:Recombinant Proteins / Q000276:immunology; D014765:Viral Vaccines / Q000627:therapeutic use*
chemical_list: D019267:Hemagglutinin Glycoproteins, Influenza Virus; D011994:Recombinant Proteins; D014765:Viral Vaccines; C109963:hemagglutinin, avian influenza A virus