Figure 1

Detection of PEDV PC22A infection by immunohistochemistry (IHC) staining using mouse anti-PEDV nucleocapsid monoclonal antibody (SD6-29). Signal of PEDV antigens were in brown color and detected in the entire villous epithelial cells in the middle jejunum of PEDV PC22A-inoculated CDCD piglets (A-D). Shortening and fusion of villi along with exfoliation of enterocytes were observed (C, D). Depending on the progress of PEDV infection, PEDV-infected villous epithelial cells still formed villi (B), detaching, swelling and undergoing necrosis (C), or highly attenuated (D). PEDV antigens extended to the villus/crypt border and were sporadically located in the crypt cell layer (CCL) in ileum obtained from CDCD (E) and conventional (F) piglets. The majority of the residual epithelial cells were PEDV-positive. In addition, PEDV antigens were detected in few mononuclear cells in dome area in ileum obtained from conventional, PEDV-inoculated piglets derived from two PEDV-exposed and recovered sows (G). No PEDV antigen was detected in the jejunum of a mock-inoculated CDCD piglet (H). Original magnifications: × 40 (A), × 200 (B-H).