Therapeutic effect of local radiation therapy combined with CpG-Stat3 siRNA treatment on TLR9⁺ BCL in mice. (A) Stat3 is constitutively activated in TLR9⁺ A20 BCL cells. Shown are results from the Western blot analysis of TLR9, activated and total Stat3 compared with β-actin used as a loading control; TLR9⁺ RAW264.7 macrophages and TLR9⁻ CD4 T cells were used for reference. (B) Mice with established SC growing A20 BCL were injected IT using CpG(B)-Stat3 siRNA, control CpG(B)-Luc siRNA, or PBS only twice daily (on days 16 and 17) before radiotherapy and then 6 hours after radiotherapy and 2 more times every other day (on days 20 and 22). Local tumor irradiation at a single 20-Gy dose on day 18 is indicated by an arrow. Shown is the A20 tumor growth kinetics in the experiment using 5 mice per each treatment group. Data are shown as means ± SEM. Statistically significant differences between groups treated with CpG(B)-Stat3 siRNA and controls treated with CpG(B)-Luc siRNA are indicated with asterisks.