Identification of antigen-specific residues on E2 glycoprotein of classical swine fever virus.
Envelope glycoprotein E2 of classical swine fever virus (CSFV) is the major antigen that induces neutralizing antibodies in infected pigs. Our previous study revealed that N-terminal 90 residues (domains B/C) of E2 play key roles in differentiating vaccine strain LPC/AHRI (subgroup 1.1) from the two field strains TD/96/TWN (subgroup 2.1) and 94.4/IL/94/TWN (subgroup 3.4) (Chang et al., 2010). This study further analyzed the reaction patterns between monoclonal antibodies (mAbs) and expressed hybrid N-terminal of E2 of the above-mentioned viruses, revealing that mAbs T33 and C2, mAbs V8 and T23, and mAbs L7 and L150 required binding sites specifically at residues 690-714 in domain B, residues 715-740 in domain C, and residues 741-765 in domain C, respectively. Site-directed mutagenesis further demonstrated that residues (713)E and (729)D were critical for antigenic specificity of field strain (94.4/IL/94/TWN), while residues (705)D and (761)K were specific for vaccine strain (LPC/AHRI). These specific residues likely mediated in determining the topography of mAb binding sites of E2 to allow for differentiation between strains based on the premise that the structural integrity of the conformational epitope is maintained.
Chang
Chia-Yi
CY
Animal Health Research Institute, Council of Agriculture, 376 Chung-Cheng Road, Tansui, Taipei, Taiwan.
Huang
Chin-Cheng
CC
Lin
Yu-Ju
YJ
Deng
Ming-Chung
MC
Tsai
Chiung-Hui
CH
Chang
Wei-Ming
WM
Wang
Fun-In
FI
D000595:Amino Acid Sequence; D000818:Animals; D000956:Antigens, Viral / Q000737:chemistry* / Q000235:genetics / Q000276:immunology*; D002460:Cell Line; D006691:Classical Swine Fever / Q000276:immunology / Q000821:virology*; D006692:Classical Swine Fever Virus / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D018604:Epitope Mapping; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D018411:Spodoptera; D013552:Swine; D014759:Viral Envelope Proteins / Q000737:chemistry* / Q000235:genetics / Q000276:immunology*
D000956:Antigens, Viral; D014759:Viral Envelope Proteins; C087086:glycoprotein E2, classical swine fever virus