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Expression and antigenicity characterization for truncated capsid protein of porcine circovirus type 2

Lou, Zhongzi, Li, Xuerui, Li, Zhiyong, Yin, Xiangping, Li, Baoyu, Lan, Xi, Yang, Bin, Zhang, Yun, Liu, Jixing
Canadian journal of veterinary research 2011 v.75 no.1 pp. 61-64
B-lymphocytes, Escherichia coli, Porcine circovirus-2, amino acids, antiserum, coat proteins, epitopes, genes, mice, monoclonal antibodies
Three pairs of specific primers were designed to amplify F2-1, F2-2, and XF2-2 truncated capsid protein genes of porcine circovirus type 2 (PCV-2). Amplified sequences were subcloned to pET-32a(+) vectors and expressed in Rosetta (DE3) Escherichia coli by induction of isopropy-β-D-thiogalactoside (IPTG). All of the fusion proteins had positive reactions to PCV-2 antiserum and His-XF2-2 showed the best reactivity. Proteins were used to immunize BALB/c mice to produce monoclonal antibodies (mAbs), and 7 mAbs were selected. Capsid protein N-terminal parts 55 to 96 amino acid (aa), 97 to 141 aa, and 143 to 211 aa were confirmed as binding regions of the 7 mAbs. Reactivity between His-XF2-2 and the 7 mAbs was detected, FmAb-8 showed the best reactivity. The dominant B-cell epitope was located at 97 to 141 aa. The PEPSCAN indicated that the P122–136 peptide contained the dominant B-cell epitope.