Ca-074Me, a cathepsin B inhibitor, rescues C. muridarum from macrophage inhibition. (A) RAW macrophages were infected at an MOI of 0.5 (black bar) or 10 (gray bar). Some cells infected at an MOI of 10 were treated with IL-1Ra at 50 μg/ml (white bar) or 100 μg/ml (crosshatched bar), Ac-YVAD-CHO (horizontally hatched bar), or Z-WEHD-FMK (obliquely hatched bar). (B) Treatment of macrophages infected at an MOI of 10 with CA-074Me. Shown are means and SD. (C to F) Representative live-microscopy images of cells at 10 h p.i. treated with the cathepsin B indicator dye MR-(RR)2 (red channel) and the nuclear stain Hoechst 33342 (blue channel). (C) Mock infected. (D) MOI = 0.5. (E) MOI = 10. (F) MOI = 10 with Ca-074Me. ****, P < 0.0001; ***, P < 0.001.