Identification of a linear epitope on the capsid protein of classical swine fever virus

Zhang, Xin; Xu, Jia; Sun, Yuan; Li, Su; Li, Na; Yang, Shuo; He, Fan; Huang, Jun-Hua; Ling, Li-Jun; Qiu, Hua-Ji

The capsid (C) protein of Classical swine fever virus (CSFV) is proposed to play an essential role in the replication and translation of the viral RNA. In this study, a monoclonal antibody (mAb) directed against the C protein was generated with the recombinant C protein expressed in Escherichia coli as immunogen. IFA and IPMA analysis showed that the native C protein of CSFV virions was reactive to the mAb. By truncating the C protein, we identified a linear epitope recognized by the mAb, corresponding to amino acids (61)TQDGLYHNKN(70) of the CSFV C protein, which is well conserved among pestiviruses. Laser confocal analysis showed that the C protein mainly locates in the cellular nucleoplasm and nucleolus of PK-15 cells. The results have implications for further study of CSFV replication.