Histology of myocardial inflammation (A) and pancreatic inflammation (B) at day 7 after CVB3 challenge. BALB/c mice were injected with Lenti-2B (1 × 108 TU/mouse) through the tail vein, at 24 h post injection, 8 × 103 pfu/mouse of CVB3 was used as the challenge, and then euthanized at day 7 post CVB3 infection. The four groups were injected with Lenti-2B or Lenti-NC or MEM but infected with CVB3 (V) or MEM only as normal control. Hematoxylin-eosin staining and immunohistochemical analysis of CVB3 or GFP were performed on the sections prepared from the hearts. Untreated Control shows the control section was treated without the first antibody in IHC staining. Green arrow shows a example of infiltration, red arrows show examples of necrosis and calcification, black arrows show examples of CVB3 infection, purple arrows show examples of GFP-expressing. Magnification, 200×.