R-848 inhibits the elicitation of CHS. Mice were sensitized with DNFB (A) and FITC (B), and challenge with the respective hapten was performed 5 and 6 days later. R-848 was injected during the challenge process. Twenty-four hours after challenge, CHS was determined as increase in ear thickness compared with the vehicle-treated ear. Immediately after measuring ear thickness, ears were harvested for immunohistochemical staining with anti-Gr-1 (C). Corresponding groups in panels B and C are labeled i-iii. Data represent means of 5 to 7 mice per group. Each experiment was repeated at least 2 times. The scale bar represents 100 μm (left column) or 50 μm (right column). Error bars indicate standard deviation. ^*Significant difference between the 2 bars.