Development and characterization of monoclonal antibodies against p30 protein of African swine fever virus

Among the structural proteins that compose the virion of African swine fever virus (ASFV), p30 is one of the most immunogenic proteins and is produced during early stage of ASFV infection. These two characteristics make p30 a good target for diagnostic assays to detect ASFV infection. In this study, we describe a panel of newly generated p30-specific monoclonal antibodies (mAbs). The reactivity of these mAbs was confirmed by immunoprecipitation and Western blot analysis in Vero cells infected with alphavirus replicon particles that express p30 (RP-p30). Furthermore, this panel of mAbs recognized ASFV strains BA71 V (Genotype I) and Georgia/2007 (Genotype II) in immunofluorescence assays on virus-infected Vero cells and swine macrophages, respectively. These mAbs also detected p30 expression by immunohistochemistry in tissue samples from ASFV-infected pigs. Epitope mapping revealed that a selected mAb from the panel recognized a linear epitope within the 32-amino acid region, 61–93. In contrast, two of the mAbs recognize the C-terminal region of the protein, which is highly hydrophilic, enriched in glutamic acid residues, and predicted to contain an intrinsically disordered protein region (IDPR). This panel of mAbs and mAb-based diagnostic assays potentially represent valuable tools for ASFV detection, surveillance and disease control.