L. intracellularis infection in epithelial cells of mouse enteroids infected by the microinjection method. A–C L. intracelularis antigen is observed on the basal region of mouse enteroids cells (black arrows). Most of the antigen is observed as amorphous clusters, instead of the typical rod-shaped morphology seen in vivo. ×400. D L. intracellularis antigen is observed on the basal region of mouse enteroids cells (black arrows) and in cellular cytoplasm (white arrows on the insert). Main image: ×100, insert: ×400. Enteroid lumens are indicated by asterisks (*).