title: Yeast-expressed classical swine fever virus glycoprotein E2 induces a protective immune response.
abstract: Classical swine fever (CSF) is an economically important swine disease worldwide. The glycoprotein E2 of classical swine fever virus (CSFV) is a viral antigen that can induce a protective immune response against CSF. A recombinant E2 protein was constructed using the yeast Pichia pastoris expression system and evaluated for its vaccine efficacy. The yeast-expressed E2 (yE2) was shown to have N-linked glycosylation and to form homodimer molecules. Four 6-week-old specified-pathogen-free (SPF) piglets were intramuscularly immunized with yE2 twice at 3-week intervals. All yE2-vaccinated pigs could mount an anamnestic response after booster vaccination with neutralizing antibody titers ranging from 1:96 to 1:768. Neutralizing antibody titers at 10 weeks post booster vaccination ranged from 1:16 to 1:64. At this time, the pigs were subjected to challenge infection with a dose of 1x10(5)TCID(50) (50% tissue culture infective dose) virulent CSFV strain. At 1 week post challenge infection, all of the yE2-immunized pigs were alive and without symptoms or signs of CSF. Neutralizing antibody titers at this time ranged from 1:4,800 to 1:12,800 and even to 1:51,200 one week later. In contrast, the control pigs continuously exhibited signs of CSF and had to be euthanized because of severe clinical symptoms at 6 days post challenge infection. All of the yE2-vaccinated pigs were E(rns) antibody negative and had seroconverted against E(rns) by post challenge day 11, suggesting that yE2 is a potential DIVA (differentiating infected from vaccinated animals) vaccine. The yeast-expressed E2 protein retains correct immunogenicity and is able to induce a protective immune response against CSFV infection.
authors.affiliation: Graduate Institute of Veterinary Microbiology, College of Veterinary Medicine, National Chung Hsing University, 250 Kuo Kuang Road, Taichung 40227, Taiwan, ROC.
authors.forename: Guang-Jan
authors.initials: GJ
authors.lastname: Lin
authors.forename: Ting-Yu
authors.initials: TY
authors.lastname: Liu
authors.forename: Yu-Yao
authors.initials: YY
authors.lastname: Tseng
authors.forename: Zeng-Weng
authors.initials: ZW
authors.lastname: Chen
authors.forename: Chia-Chin
authors.initials: CC
authors.lastname: You
authors.forename: Shih-Ling
authors.initials: SL
authors.lastname: Hsuan
authors.forename: Maw-Sheng
authors.initials: MS
authors.lastname: Chien
authors.forename: Chienjin
authors.initials: C
authors.lastname: Huang
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000235:genetics / Q000276:immunology; D006691:Classical Swine Fever / Q000276:immunology* / Q000517:prevention & control* / Q000821:virology; D006692:Classical Swine Fever Virus / Q000235:genetics / Q000276:immunology*; D004279:DNA, Viral / Q000235:genetics / Q000276:immunology; D010843:Pichia / Q000235:genetics; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology; D012441:Saccharomyces cerevisiae / Q000235:genetics; D013047:Specific Pathogen-Free Organisms; D034421:Sus scrofa; D022223:Vaccines, Subunit / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology; D014759:Viral Envelope Proteins / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D014765:Viral Vaccines / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*
chemical_list: D000914:Antibodies, Viral; D004279:DNA, Viral; D011994:Recombinant Proteins; D022223:Vaccines, Subunit; D014759:Viral Envelope Proteins; D014765:Viral Vaccines; C087086:glycoprotein E2, classical swine fever virus