A total of 213 pig blood samples were collected from Aug 2013 to Apr 2019 from local farms in Zhejiang Province. Serum was separated from blood samples by centrifugation at 1500 × g for 10 min and kept at -20 °C until use.
Previously produced mouse anti-S1 monoclonal antibody 6B4/6G1/1C11 could recognize S1T1, S1T2, S1T3, respectively. PEDV positive serum and mouse anti-His monoclonal antibody (Beyotime, China) were used as primary antibody. HRP-labeled goat anti-mouse IgG antibody (Beyotime, China). HRP-labeled goat anti-pig IgG antibody (Lifetechnology, USA), Alexa Fluor 488-conjugated goat anti-pig IgA antibody (Lifetechnology, USA) and Alexa Fluor 568-conjugated goat anti-mouse IgG antibody (Lifetechnology, USA) were used as secondary antibody.