Development of a monoclonal antibody-based competitive ELISA for serological detection of lumpy skin disease virus

Lumpy skin disease (LSD) is a transboundary viral disease of cattle caused by lumpy skin disease virus (LSDV), resulting in substantial economic losses and posing a serious threat to the global cattle industry and international trade. Effective serological surveillance is essential for disease control and for evaluating vaccination programs. However, most currently available serological assays rely on a limited number of viral structural proteins as antigens, which restricts antigen diversity and may limit their applicability, particularly in the development of DIVA-compatible diagnostic strategies, highlighting the need to explore alternative diagnostic targets. In this study, we developed a monoclonal antibody-based competitive enzyme-linked immunosorbent assay (cELISA) targeting LSDV001, a highly conserved protein among Capripoxvirus species. Although LSDV001 is not a classical structural protein, it was consistently detected in purified virions and specifically recognized by antibodies in bovine immune sera, supporting its relevance as a serological target. A high-affinity monoclonal antibody (8E5) was generated and used to establish the cELISA. Receiver-operating characteristic (ROC) curve analysis showed that the sensitivity and specificity of the assay were 96.83 and 98.00%. The assay showed good reproducibility, no detectable cross-reactivity with other bovine pathogens, and strong agreement with the virus neutralization test (VNT). Further evaluation using 148 field serum samples demonstrated an overall concordance rate of 95.3% with VNT, with a Cohen's kappa coefficient of 0.913, indicating substantial agreement between the two methods. Collectively, this LSDV001-based cELISA provides a sensitive and practical tool for large-scale serological surveillance and evaluation of vaccination responses against LSD.