title: Antigenic mimicking with cysteine-based cyclized peptides reveals a previously unknown antigenic determinant on E2 glycoprotein of classical swine fever virus.
abstract: Envelope glycoprotein E2 of classical swine fever virus (CSFV) is the major antigen that induces neutralizing antibodies in infected pigs. The conformational epitope(s) on B/C domains were mapped to the N-terminal 90 residues of E2 between amino acids 690 and 779 (Chang et al., 2010a). To mimic the conformational epitopes, a set of synthetic cyclized peptides spanning the B/C domains of E2 were used to react with monoclonal antibodies (mAbs) against E2 and with swine anti-CSFV polyclonal sera. All antibodies recognized a highest common element, (753)RYLASLHKKALPTSV(767), on the double-looped peptides. This epitope region has not been revealed previously in the literature. Both substitution-scanning of residues (753)RYLASLHKKALPTSV(767) on a double-looped peptide and site-directed mutagenesis of expressed E2 demonstrated that residues (761)K, (763)L and (764)P were critical for the reactivity with mAbs. In addition, the up- and downstream residues (753)R, (754)Y, (755)L and (765)T were also crucial. Alignment showed that this stretch of amino acids was relatively conserved among various CSFVs. Thus, we identified a motif (753)RYLASLHKKALPT(765), which may be part of group-specific antigen and important for the structural integrity of conformational epitope recognition.
authors.affiliation: Animal Health Research Institute, Council of Agriculture 376 Chung-Cheng Road, Tansui, New Taipei City 25158, Taiwan.
authors.forename: Chia-Yi
authors.initials: CY
authors.lastname: Chang
authors.forename: Chin-Cheng
authors.initials: CC
authors.lastname: Huang
authors.forename: Ming-Chung
authors.initials: MC
authors.lastname: Deng
authors.forename: Yeou-Liang
authors.initials: YL
authors.lastname: Huang
authors.forename: Yu-Ju
authors.initials: YJ
authors.lastname: Lin
authors.forename: Hsin-Meng
authors.initials: HM
authors.lastname: Liu
authors.forename: Yeou-Liang
authors.initials: YL
authors.lastname: Lin
authors.forename: Fun-In
authors.initials: FI
authors.lastname: Wang
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000914:Antibodies, Viral / Q000276:immunology; D000956:Antigens, Viral / Q000276:immunology*; D006692:Classical Swine Fever Virus / Q000276:immunology*; D003545:Cysteine / Q000737:chemistry; D004252:DNA Mutational Analysis; D018604:Epitope Mapping; D000939:Epitopes / Q000276:immunology*; D010456:Peptides, Cyclic / Q000737:chemistry / Q000276:immunology*; D013552:Swine; D014759:Viral Envelope Proteins / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral; D000956:Antigens, Viral; D000939:Epitopes; D010456:Peptides, Cyclic; D014759:Viral Envelope Proteins; C087086:glycoprotein E2, classical swine fever virus; D003545:Cysteine