Figure 1. miR-155^−/− mice develop attenuated CVB3-induced VM.

miR-155^−/− and WT mice received 1 × 10⁵ PFU of CVB3 or PBS i.p. on day 0 and the heart samples were isolated on day 7. (A) miR-155 expression was determined by real-time PCR in hearts or heart infiltrating cells from CVB3 or PBS injected WT mice. (B) Heart sections of CVB3-infected WT and miR-155^−/− KO mice were stained with H&E, and the severity of myocarditis was assessed as the percentage of the heart section with inflammation compared with the overall size of the heart section, with the aid of a microscope eyepiece grid. Scale bar = 100 μm. (C) Myocardial infiltration of CD45⁺ cells was determined by FACS. (D) Viral titers were measured using plaque assay. Experiments were repeated three times in triplicate with 8 mice per group. Bar graph data are presented as mean ± SD; *P < 0.05 and **P < 0.01 as compared with WT. WT: wildtype mice; KO: knockout mice; NS: no significance. Similar data presentation will appear in the subsequent figures.