Development of a neutralizing monoclonal antibody recognizing a conserved epitope of CDV-H protein and its colloidal gold test strip for antigen detection

Canine distemper virus (CDV) is currently a significant viral disease that poses a threat to the health of pets and the breeding of fur-bearing animals. It is crucial to develop a diagnostic method that can be performed on-site, is simple to execute, and yields intuitively visible results. In this study, a neutralizing monoclonal antibody(mAb) 5-8H targeting the CDV-H protein was developed and characterized. The mAb 5-8H specifically recognizes prevalent CDV strains. The minimal linear epitopes recognized by 5-8H were identified as epitopes 498-607aa, with key amino acids being 531D, 552R, 554T, and 599R. These four key antigenic sites exhibited a high degree of conservation among all CDV strains, with conservatism ranging from 94.39 % to 99.78 %. The three-dimensional structural revealed that the antigenic epitope was exposed on the surface of the CDV-H protein, making it accessible for binding with antibody. Based on mAb 5-8H, a highly sensitive and specific colloidal gold test strip for detecting CDV was developed. This method achieves a concordance rate of 96 % with RT-qPCR and is suitable for rapid detection of CDV.