Syk, but not Src, activation by TLR9 signals is restricted to ZAP-70–positive cells. (A) BH3 proteins expressed in purified B cells from 1 tonsil or from CLL patients stimulated with anti-IgM or costimulated with DSP30/IL-2 for the time points as indicated. (B) Expression profile of BCR-related signaling molecules in ZAP-70–negative and ZAP-70–positive CLL cells stimulated with DSP30 over a time course of 48 hours. One out of 3 independent experiments are shown. (C) Syk or ZAP-70 was immunoprecipitated from DSP30-stimulated Zap-70–positive cells at the time points as indicated. Blots were probed with P-Tyr319/T352-ZAP-70/Syk antibody or with ZAP-70/Syk antibodies, respectively. (D) Expression profile of BCR-related signaling molecules in CLL cells treated with or without DSP30 for 48 hours. Data show western blot analysis of n = 4 representative patient samples out of n = 6 tested. Samples were encrypted and anonymized by V numbers.