Thymic hypocellularity upon triggering TLR7. Mice were treated with PBS or 1 mg/kg per day of R848 for 7 days. (A) Thymus was hypocellular in C57BL/6 mice but not in knockout mice upon treatment with R848. Thymocytes were counted manually and normalized to total thymocyte counts of the corresponding mock-treated animals. Error bars indicate 95% confidence intervals. (B) Relative cell numbers in each thymocyte subset were measured in C57BL/6 mice by staining for CD4 and CD8, followed by flow cytometric analysis. Error bars indicate standard error. For C57BL/6 animals data from 3 independent experiments, each with N = 3, were pooled; N = 3 for knockout mice.