Identification and Characterization of Three Novel B-Cell Epitopes in African Swine Fever Virus p22 Protein

African swine fever virus (ASFV) is a highly contagious pathogen causing African swine fever in wild boars, warthogs and domestic pigs. The disease leads tosubstantial economic losses to the global pork industry and poses a grave threat to biodiversity. The early-encoded structural protein p22, owing to its immunodominant characteristics and high conservation across most genotypes, represents a promising diagnostic target and subunit vaccine candidate. In this study, the soluble extracellular domain of p22 protein (aa 30–177) was successfully expressed and purified, yielding 1.220 g/L. Eleven strains of monoclonal antibodies against p22 were generated, with four selected for B-cell epitope screening. Bioinformatic prediction-guided design was employed to generate overlapping truncations and peptides for epitope mapping. Based on those strategies, three novel linear B-cell epitopes were identified to be 30KKQQPPKK37, 130WGTDDCTG137 and 150YVYNNPHH157 by monoclonal antibodies. Sequence alignment across ASFV isolates revealed 100% evolutionary conservation in genotypes I/II, with minor variation in genotypes IV/VIII/XX/XXII. This study provided valuable data for broadening the ASFV antigen spectrum and identifying immunological targets for subunit vaccine formulation strategies.