title: Seven major genomic deletions of vaccinia virus Tiantan strain are sufficient to decrease pathogenicity.
abstract: Attenuated strain TTVAC7, as a multi-gene-deleted vaccinia virus Tiantan strain (VTT), was constructed by knocking out parts of non-essential genes related to virulence, host range and immunomodulation of VTT, and by combining double marker screening with exogenous selectable marker knockout techniques. In this study, shuttle vector plasmids pTC-EGFP, pTA35-EGFP, pTA66-EGFP, pTE-EGFP, pTB-EGFP, pTI-EGFP and pTJ-EGFP were constructed, which contained seven pairs of recombinant arms linked to the early and late strong promoter pE/L, as well as to enhanced green fluorescent protein (EGFP) as an exogenous selectable marker. BHK cells were co-transfected/infected successively with the above plasmids and VTT or gene-deleted VTT, and homologous recombination and fluorescence plaque screening methods were used to knock out the gene fragments (TC: TC7L ∼ TK2L; TA35: TA35L; TA66: TA66R; TE: TE3L ∼ TE4L; TB: TB13R; TI: TI4L; TJ: TJ2R). The Cre/LoxP system was then applied to knock out the exogenous selectable marker, and ultimately the gene-deleted attenuated strain TTVAC7 was obtained. A series of in vivo and in vitro experiments demonstrated that not only the host range of TTVAC7 could be narrowed and its toxicity weakened significantly, but its high immunogenicity was maintained at the same time. These results support the potential of TTVAC7 to be developed as a safe viral vector or vaccine.
authors.affiliation: Institute of Military Veterinary Medicine, Academy of Military Medical Science, Changchun 130122, PR China; Jiang su Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, PR China.
authors.forename: Yiquan
authors.initials: Y
authors.lastname: Li
authors.affiliation: Institute of Military Veterinary Medicine, Academy of Military Medical Science, Changchun 130122, PR China; Jiang su Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, PR China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Sheng
authors.affiliation: Institute of Military Veterinary Medicine, Academy of Military Medical Science, Changchun 130122, PR China; The Affiliated Hospital of Changchun University of Traditional Chinese Medicine, Changchun 130021, PR China.
authors.forename: Yunjie
authors.initials: Y
authors.lastname: Chu
authors.affiliation: Institute of Military Veterinary Medicine, Academy of Military Medical Science, Changchun 130122, PR China; Department of Gastroenterology, The First Hospital of Jilin University, Changchun 130021, PR China.
authors.forename: Huifan
authors.initials: H
authors.lastname: Ji
authors.affiliation: Institute of Military Veterinary Medicine, Academy of Military Medical Science, Changchun 130122, PR China; Jiang su Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, PR China.
authors.forename: Shuang
authors.initials: S
authors.lastname: Jiang
authors.affiliation: Institute of Military Veterinary Medicine, Academy of Military Medical Science, Changchun 130122, PR China; Jiang su Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, PR China.
authors.forename: Tian
authors.initials: T
authors.lastname: Lan
authors.affiliation: Institute of Military Veterinary Medicine, Academy of Military Medical Science, Changchun 130122, PR China; Jiang su Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, PR China.
authors.forename: Min
authors.initials: M
authors.lastname: Li
authors.affiliation: Institute of Military Veterinary Medicine, Academy of Military Medical Science, Changchun 130122, PR China; Jiang su Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, PR China.
authors.forename: Shuang
authors.initials: S
authors.lastname: Chen
authors.affiliation: Institute of Military Veterinary Medicine, Academy of Military Medical Science, Changchun 130122, PR China; Jiang su Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, PR China.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Fan
authors.affiliation: Institute of Military Veterinary Medicine, Academy of Military Medical Science, Changchun 130122, PR China; The Affiliated Hospital of Changchun University of Traditional Chinese Medicine, Changchun 130021, PR China.
authors.forename: Wenjie
authors.initials: W
authors.lastname: Li
authors.affiliation: Institute of Military Veterinary Medicine, Academy of Military Medical Science, Changchun 130122, PR China; Jiang su Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, PR China. Electronic address: lixiao06@mails.jlu.edu.cn.
authors.forename: Xiao
authors.initials: X
authors.lastname: Li
authors.affiliation: Institute of Military Veterinary Medicine, Academy of Military Medical Science, Changchun 130122, PR China; Department of Head and Neck Surgery, Tumor Hospital of Jilin Province, Changchun 130012, PR China. Electronic address: linjiaxiaoya@163.com.
authors.forename: Lili
authors.initials: L
authors.lastname: Sun
authors.affiliation: Institute of Military Veterinary Medicine, Academy of Military Medical Science, Changchun 130122, PR China; Jiang su Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, PR China; Department of Head and Neck Surgery, Tumor Hospital of Jilin Province, Changchun 130012, PR China. Electronic address: skylee6226@163.com.
authors.forename: Ningyi
authors.initials: N
authors.lastname: Jin
mesh_terms: D000818:Animals; D002460:Cell Line; D002522:Chlorocebus aethiops; D004274:DNA, Recombinant; D004285:Dogs; D017353:Gene Deletion; D005822:Genetic Vectors / Q000235:genetics; D016679:Genome, Viral; D057809:HEK293 Cells; D006801:Humans; D061985:Madin Darby Canine Kidney Cells; D051379:Mice; D009500:Neutralization Tests; D011817:Rabbits; D014162:Transfection; D014616:Vaccinia virus / Q000235:genetics* / Q000276:immunology / Q000472:pathogenicity* / Q000502:physiology; D014709:Vero Cells; D014774:Virulence; D014779:Virus Replication
chemical_list: D004274:DNA, Recombinant
keywords: Attenuated vaccinia virus vector; Immunogenicity; Tiantan strain; Virulence