Microfilament changes observed by fluorescence microscopy. IPEC-J2 cells were infected with PCV2 at 3×102.5 TCID50/ml. For actin staining at 1, 24, 48 and 72 h p.i., cells were fixed with paraformaldehyde and permeabilized with Triton X-100. F-actin was detected by phalloidin-FITC. DAPI was used as a nuclear counterstain. Images were obtained using a fluorescence microscope (ZEISS Observer.Z1). Magnification 400x.