title: Attenuation of bovine herpesvirus type 1 by deletion of its glycoprotein G and tk genes and protection against virulent viral challenge.
abstract: To develop a novel vaccine against infectious bovine rhinotracheitis (IBR), a bovine herpesvirus-1 (BoHV-1) mutant was constructed by deleting the genes for glycoprotein G (gG) and thymidine kinase (tk) through homologous recombination. The resulting sequences for both genes were shown to be correct and a gG expression defect was also confirmed. A parallel study of the BoHV-1 gG(-)/tk(-), gE(-)/tk(-) mutants and wild type (wt) in 31 calves was performed at three different doses, 4×10(5)PFU, 4×10(6)PFU and 4×10(7)PFU. Compared to wt BoHV-1, inoculation of BoHV-1 gG(-)/tk(-) and gE(-)/tk(-) produced no clinical signs and the virus was not reactivated by dexamethasone (dex). Inoculation of BoHV-1 gG(-)/tk(-) at the doses of 4×10(6) and 4×10(7)PFU provided full clinical protection for the cattle against wt BoHV-1 challenge at 4×10(7)PFU/calf. Although the mutants were associated with significantly lower levels of serum neutralizing antibody, interferon gamma (IFN-γ) and tumor necrosis factor alpha (TNF-α) than wt BoHV-1 on days 3, 5 and 7 after immunization, stimulation of IFN-β by BoHV-1 gG(-)/tk(-) was significantly higher than that of wt BoHV-1 and gE(-)/tk(-) on days 3 and 5. We conclude that BoHV-1 gG(-)/tk(-) was attenuated adequately and that it maintains the ability to stimulate immune protection. Therefore, it may be a promising candidate for a marker vaccine against IBR.
authors.affiliation: The State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Minmin
authors.initials: M
authors.lastname: Zhang
authors.forename: Shulin
authors.initials: S
authors.lastname: Fu
authors.forename: Mingliang
authors.initials: M
authors.lastname: Deng
authors.forename: Qian
authors.initials: Q
authors.lastname: Xie
authors.forename: Haiyang
authors.initials: H
authors.lastname: Xu
authors.forename: Zhengfei
authors.initials: Z
authors.lastname: Liu
authors.forename: Changmin
authors.initials: C
authors.lastname: Hu
authors.forename: Huanchun
authors.initials: H
authors.lastname: Chen
authors.forename: Aizhen
authors.initials: A
authors.lastname: Guo
mesh_terms: D000818:Animals; D057134:Antibodies, Neutralizing / Q000097:blood; D000914:Antibodies, Viral / Q000097:blood; D002417:Cattle; D002460:Cell Line; D005260:Female; D017353:Gene Deletion; D007242:Herpesvirus 1, Bovine / Q000235:genetics / Q000472:pathogenicity*; D007241:Infectious Bovine Rhinotracheitis / Q000276:immunology / Q000517:prevention & control*; D007371:Interferon-gamma / Q000276:immunology; D008297:Male; D011817:Rabbits; D013937:Thymidine Kinase / Q000235:genetics*; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology; D014764:Viral Proteins / Q000235:genetics*; D014765:Viral Vaccines / Q000235:genetics / Q000276:immunology*; D017201:Virus Shedding
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D014409:Tumor Necrosis Factor-alpha; D014764:Viral Proteins; D014765:Viral Vaccines; C046998:bovine herpesvirus type-1 glycoproteins; D007371:Interferon-gamma; D013937:Thymidine Kinase