The Novel Antigenic Epitopes of African Swine Fever Virus Inner Membrane p54 Protein Revealed by Monoclonal Antibodies.

African swine fever (ASF) is caused by the African swine fever virus (ASFV); infection in domestic pigs and wild boars leads to a highly contagious, hemorrhagic disease. The p54 protein is encoded by the ASFV E183L gene and is an important structural protein located on the inner envelope of the virus. It is involved in processes of virus assembly, apoptosis induction, and neutralizing antibody production. In this study, three specific monoclonal antibodies (mAbs) against ASFV p54 protein were generated, namely 6B11, 3E3, and 3C10, from mice who were immunized with recombinant prokaryotic p54-truncated protein. Three novel linear B cell epitopes, recognized by the mAbs, were revealed: ⁶⁰AAIEEEDIQFINP⁷², ¹²⁸MATGGPAAAPAAASAPAHPAE¹⁴⁸, and ¹⁶³MSAIENLRQRNTY¹⁷⁵. The epitopes ⁶⁰AAIEEEDIQFINP⁷² and ¹⁶³MSAIENLRQRNTY¹⁷⁵ were highly conserved in genotype I and II ASFV strains. In addition, the epitope peptide ELISA can be used for the detection of ASFV antibodies. Our work provides new insights for p54 antigenicity and an alternative tool for serological diagnosis of ASF.