Prokaryotic expression of porcine deltacoronavirus S gene truncated segment and establishment of indirect ELISA detection method.

Porcine deltacoronavirus (PDCoV) is an emerging discovered coronavirus that causes significant losses in the global swine industry. This study aimed to establish an indirect ELISA method for detecting PDCoV antibodies using the truncated gene of PDCoV spike protein (S). The purified S protein was used as the coating antigen for the polyclonal antibody. The conditions were optimized to establish an indirect ELISA detection method for PDCoV based on the S protein, which showed good specificity and no cross-reaction with SVV-VP1, ASFV-P72, GETV-E2, PRV-gE, etc. The method has high repeatability, with coefficients of variation within and between batches less than 10%. Compared with the commercial kit, the positive coincidence rate is 86.40%, the negative coincidence rate is 89.43%, and the total coincidence rate is 91.76%. This ELISA can be used for PDCoV serological investigation and antibody evaluation. It can also lay the foundation for further research and development of PDCoV S protein ELISA antibody detection kit.