A new B cell epitope of pC129R protein of African swine fever virus identified by monoclonal antibodies.

African swine fever virus (ASFV) is a most important pathogen which causes huge damage in swine production in the world. pC129R protein is one of the most abundant ASFV proteins in infected Vero cells and WSL-HP cells, which consequently could be a target for ASF detection and surveillance. In this study, 5-6-week-old female BALB/c mice were immunized with rpC129R protein expressed by a prokaryotic system. And three hybridomas, 1B1, 1B4 and 4H4, steadily secreted anti-pC129R monoclonal antibodies were screened by an indirect enzyme linked immunosorbent assay (ELISA). Among them, 1B4 and 4H4 had IgG2a isotype with Kappa light chain, while 1B1 had IgG1 isotype with Kappa light chain. Western blot and indirect immunofluorescence assay showed that three monoclonal antibodies (mAbs) specifically reacted with ASFV. Epitope mapping was performed with truncated polypeptides. And a new B cell epitope, 18KHYVLIPK25 was identified by the mAbs, which was highly conserved in most genotypes of ASFV. These findings not only provide a monoclonal antibody tool for further study of the function of C129R, but also lay the foundation for serological diagnosis and vaccine development.