Fig. 1

TLR9 is highly expressed in B-ALL cells and an independent prognostic factor for B-ALL A. Real-time qRT-PCR results of the TLR9 expression profile in PBMC from 49 B-ALL patients and 10 healthy controls and normalized to the expression of β-actin. The expression level of TLR9 in the PBMC of B-ALL patients was significantly higher than that of healthy people (Medium: 0.004 vs. 0.067). All data are shown with medium and interquartile range. Significant difference was p < 0.001. B Cox multivariate model indicated that the expression level of TLR9 is an independent prognostic factor of B-ALL, which is related to PFS (mPFS: 29.0 months vs. 9.0 months, p = 0.005, HR: 8.091) and OS (mOS: undefined vs. 16.0 months, p = 0.018, HR: 5.799). And B-ALL patients with high TLR9 expression have a better prognosis. C CpG 685 inhibits proliferation in BLIN-1 cells. WST-1 cell viability assay results showing kinetic changes in BLIN-1 cell number after 3 day culture in media with different doses of CpG 685. Columns represent means of 5 independent experiments; bars represent SD. **p < 0.01. D CpG 685 induces apoptosis in BLIN-1 cells. Viable BLIN-1 cells cultured in media with different doses of CpG 685 after 3-day culture were examined by annexin-V/7AAD staining. The percentage of apoptotic BLIN-1 cells was calculated. CpG 685 induces BLIN-1 cells to apoptosis in a CpG 685 dose-dependent manner. E The percentage of Annexin-V⁺ cells in BLIN-1 cells (fold) with different doses of CpG 685 after 3 day culture was analyzed by flow cytometry. Columns represent means of 3 independent experiments; bars represent SEM. *p < 0.05. F CpG 685 upregulates CD40, CD80, CD86, MHC-I, and MHC-II expression, further promoting the antigen presentation function of BLIN-1 cells. G The folds of costimulatory molecules on the surface of BLIN-1 cells were upregulated after 24 h of CpG 685 stimulation compared with those without CpG 685. The red line represents no upregulation. Columns represent means of 3 independent experiments; bars represent SEM