title: Efficacy evaluation of the C-strain-based vaccines against the subgenotype 2.1d classical swine fever virus emerging in China.
abstract: Classical swine fever (CSF) is a devastating infectious disease of pigs caused by classical swine fever virus (CSFV). The disease has been controlled following extensive vaccination with the lapinized attenuated vaccine C-strain for decades in China. However, frequent CSF outbreaks occurred recently in a large number of C-strain-vaccinated pig farms in China and a new subgenotype 2.1d of CSFV has been reported to be responsible for the outbreaks. Here we analyzed the molecular variations and antigenic differences among the C-strain-based commercial vaccines of different origins from different manufacturers in China, and reevaluated the vaccines against the emerging subgenotype 2.1d strain of CSFV. The results showed that the C-strain adapted to the continuous ST cell line (CST) contain a unique M290K variation on the E2 protein, compared to those of primary BT cells (CBT) or rabbit origin (CRT) and the traditional C-strain sequences available in the GenBank database. Serum neutralization test revealed the antigenic differences between CSTand CBTor CRT. Notably, the neutralizing titers of porcine anti-C-strain sera against the CSFV isolate of subgenotype 2.1d were significantly lower than those against C-strain or Shimen strain. The C-strain-vaccinated, subgenotype 2.1d HLJZZ2014 strain-challenged pigs did not show any clinical signs and all survived. However, these pigs displayed mild pathological and histological lesions, and the CSFV viral RNA was detected in the various tissue and blood samples. Taken together, the C-strain-based vaccines of different origins showed molecular variations and antigenic differences, and could provide clinical but not pathological and virological protection against the subgenotype 2.1d CSFV emerging in China. Further investigation is needed to comprehensively assess the efficacy of C-strain of different doses against the subgenotype 2.1d CSFV.
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Road, Harbin 150069, PR China.
authors.forename: Yuzi
authors.initials: Y
authors.lastname: Luo
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Road, Harbin 150069, PR China.
authors.forename: Shengwei
authors.initials: S
authors.lastname: Ji
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Road, Harbin 150069, PR China.
authors.forename: Jian-Lin
authors.initials: JL
authors.lastname: Lei
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Road, Harbin 150069, PR China.
authors.forename: Guang-Tao
authors.initials: GT
authors.lastname: Xiang
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Road, Harbin 150069, PR China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Road, Harbin 150069, PR China.
authors.forename: Yao
authors.initials: Y
authors.lastname: Gao
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Road, Harbin 150069, PR China.
authors.forename: Xing-Yu
authors.initials: XY
authors.lastname: Meng
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Road, Harbin 150069, PR China.
authors.forename: Guanglai
authors.initials: G
authors.lastname: Zheng
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Road, Harbin 150069, PR China.
authors.forename: En-Yu
authors.initials: EY
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Road, Harbin 150069, PR China.
authors.forename: Yimin
authors.initials: Y
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Road, Harbin 150069, PR China.
authors.forename: Ming-Liang
authors.initials: ML
authors.lastname: Du
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Road, Harbin 150069, PR China.
authors.forename: Yongfeng
authors.initials: Y
authors.lastname: Li
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Road, Harbin 150069, PR China.
authors.forename: Su
authors.initials: S
authors.lastname: Li
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Road, Harbin 150069, PR China. Electronic address: hexijun@caas.cn.
authors.forename: Xi-Jun
authors.initials: XJ
authors.lastname: He
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Road, Harbin 150069, PR China. Electronic address: sunyuan@hvri.ac.cn.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Sun
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Road, Harbin 150069, PR China. Electronic address: huajiqiu@hvri.ac.cn.
authors.forename: Hua-Ji
authors.initials: HJ
authors.lastname: Qiu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood*; D000940:Antigenic Variation; D002681:China; D006691:Classical Swine Fever / Q000276:immunology / Q000473:pathology / Q000517:prevention & control* / Q000821:virology; D006692:Classical Swine Fever Virus / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D005838:Genotype; D016415:Sequence Alignment / Q000662:veterinary; D013552:Swine; D014611:Vaccination / Q000662:veterinary*; D014613:Vaccines, Attenuated; D014765:Viral Vaccines / Q000235:genetics / Q000276:immunology*
chemical_list: D000914:Antibodies, Viral; D014613:Vaccines, Attenuated; D014765:Viral Vaccines
keywords: C-strain vaccines; Classical swine fever virus; Efficacy; Subgenotype 2.1d