Decreased numbers of CD8+T cells and macrophages at the sites of C protein-induced myositis (CIM) in mast cell-deficient W/Wvmice. CIM was induced in W/Wv mice and control congenic wild-type (WT) mice. Twenty-one days after the induction, specimens of muscle were stained with anti-CD8 antibody, anti-F4/80 antibody, and TO-PRO-3 (nuclear staining). Representative photomicrographs of CD8+ cells (a) and F4/80+ cells (b) in skeletal muscle in W/Wv mice and WT mice are shown. Mean ± standard deviation of the numbers of CD8+ cells (c) and F4/80+ cells (d) (per mm2) is shown. n = 6 mice in each group. *Significantly different from the mean value of WT mice (P <0.01). ND, not detectable.