Mapping of Epitope and Determination of cDNA Sequences of Variable Region of MAbs Against E2 Protein of Classical Swine Fever Virus

Structural and envelope glycoprotein E2 (gp55) of Classical swine fever virus (CSFV) is the most antigenic protein being responsible for eliciting neutralizing antibodies and conferring protective immunity. Infection of cells with CSFV is mediated by the interaction of E2 and Erns with the cell surface receptor. In this paper we report the analysis of E2 epitope by screening a 12-mer random peptide phage display library using the monoclonal antibodies (MAbs), c2410 and a18, raised against CSFV strain alfort Tübingen and reacted with the E2 structural protein. MAbs, c2410 and a18 recognized the same linear epitope, located at aa832- aa 837 (SPTTLR) of E2 protein, but showed some different reactivities with the mimotopes by ELISA and Western blot analysis. Sequencing both cDNA of light chain and heavy chain variable regions of the two MAbs from total RNA of the hybridoma cells was carried out. The results showed that MAb c2410 and MAb a18 are different monoclonal antibodies, though both MAbs derived from the same fusion and recognized the same epitope.