title: The adaptation of a CTN-1 rabies virus strain to high-titered growth in chick embryo cells for vaccine development.
abstract: BACKGROUND
  Rabies virus is the causative agent of rabies, a central nervous system disease that is almost invariably fatal. Currently vaccination is the most effective strategy for preventing rabies, and vaccines are most commonly produced from cultured cells. Although the vaccine strains employed in China include CTN, aG, PM and PV, there are no reports of strains that are adapted to primary chick embryo cells for use in human rabies prevention in China.
  
  
  RESULTS
  Rabies virus strain CTN-1 V was adapted to chick embryo cells by serial passage to obtain the CTNCEC25 strain. A virus growth curve demonstrated that the CTNCEC25 strain achieved high titers in chick embryo cells and was nonpathogenic to adult mice by intracerebral inoculation. A comparison of the structural protein genes of the CTNCEC25 strain and the CTN-1 V strain identified eight amino acid changes in the mature M, G and L proteins. The immunogenicity of the CTNCEC25 strain increased with the adaptation process in chick embryo cells and conferred high protective efficacy. The inactivated vaccine induced high antibody responses and provided full protection from an intramuscular challenge in adult mice.
  
  
  CONCLUSIONS
  This is the first description of a CTNCEC25 strain that was highly adapted to chick embryo cells, and both its in vitro and in vivo biological properties were characterized. Given the high immunogenicity and good propagation characteristics of the CTNCEC25 strain, it has excellent potential to be a candidate for development into a human rabies vaccine with high safety and quality characteristics for controlling rabies in China.
authors.affiliation: Shenzhen Weiguang Biological Products Co,, Ltd, Shenzhen 518107, Guangdong province, China. gcpzxy0402@aliyun.com.
authors.forename: Caiping
authors.initials: C
authors.lastname: Guo
authors.forename: Chunhua
authors.initials: C
authors.lastname: Wang
authors.forename: Shan
authors.initials: S
authors.lastname: Luo
authors.forename: Shimao
authors.initials: S
authors.lastname: Zhu
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.forename: Yongdi
authors.initials: Y
authors.lastname: Liu
authors.forename: Lanzhen
authors.initials: L
authors.lastname: Zhou
authors.forename: Pei
authors.initials: P
authors.lastname: Zhang
authors.forename: Xin
authors.initials: X
authors.lastname: Zhang
authors.forename: Yujiang
authors.initials: Y
authors.lastname: Ding
authors.forename: Weirong
authors.initials: W
authors.lastname: Huang
authors.forename: Kaiyong
authors.initials: K
authors.lastname: Wu
authors.forename: Yanpeng
authors.initials: Y
authors.lastname: Zhang
authors.forename: Weihua
authors.initials: W
authors.lastname: Rong
authors.forename: Hua
authors.initials: H
authors.lastname: Tian
mesh_terms: D000220:Adaptation, Biological; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D002478:Cells, Cultured; D002642:Chick Embryo; D002681:China; D004195:Disease Models, Animal; D051379:Mice; D008969:Molecular Sequence Data; D017354:Point Mutation; D012367:RNA, Viral / Q000235:genetics; D011818:Rabies / Q000276:immunology / Q000517:prevention & control; D011819:Rabies Vaccines / Q000008:administration & dosage / Q000276:immunology* / Q000302:isolation & purification*; D011820:Rabies virus / Q000254:growth & development / Q000276:immunology / Q000502:physiology*; D017422:Sequence Analysis, DNA; D012692:Serial Passage; D014764:Viral Proteins / Q000235:genetics
chemical_list: D000914:Antibodies, Viral; D012367:RNA, Viral; D011819:Rabies Vaccines; D014764:Viral Proteins