Fig. 6

CpG 685 treatment reduces B-ALL burden systemically in vivo. A CpG 685 treatment reduces BLIN-1 cell engraftment in NCG mouse xenograft models. Cohorts of mice were i.v. injected with 5 × 10⁶ BLIN-1 cells, which led to the development of a lethal leukemia that killed all BLIN-1 mice within 6 weeks. After 15 days, cohorts of mice were also i.p. injected with 2 mg/kg CpG 685 or PBS control for the next 5 days. On day 30, flow cytometry was used to detect the percentage of hCD19⁺hCD45⁺/mCD45⁺ cells in peripheral blood, spleen and bone marrow. The percentage of hCD19⁺hCD45⁺/mCD45⁺ cells represent BLIN-1 cells infiltrating in peripheral blood, spleen and bone marrow. The infiltration degree of BLIN-1 cells in bone marrow, spleen and peripheral blood of mice was different, mainly in bone marrow, followed by spleen. Compared with PBS, CpG 685 could significantly inhibit the infiltration of BLIN-1 cells in bone marrow, spleen and peripheral blood, especially the infiltration of BLIN-1 cells in bone marrow. (left panel) Aggregated results detected from 5 BLIN-1 mice of each group and are presented as the mean ± SD (right panel). *p < 0.05, **p < 0.01. B Survival curve of BLIN-1 mice of each group (7 mice per group). CpG 685 significantly prolonged the survival of BLIN-1 mice compared with PBS (median survival: 32 days vs. 47 days, HR: 0.206). p = 0.0005. C Survival curve of B-ALL PDX mice of each group (7 mice per group). CpG 685 significantly prolonged the survival of B-ALL PDX mice compared with PBS (median survival: 20 days vs. 30 days, HR: 0.228). P = 0.0002. D CpG 685 treatment on B-ALL PDX model. Cohorts of mice were i.v. injected with 1 × 10⁶ B-ALL cells. At days 10, blood is taken through the tail vein to check the tumor burden. According to the proportion of hCD19⁺hCD45⁺/mCD45⁺ cells in peripheral blood, PDX model mice were divided into two groups. Each cohort of mice were also i.p. injected with 2 mg/kg CpG 685 or PBS control for the next 5 days. On day 22, flow cytometry was used to detect the percentage of hCD19⁺hCD45⁺/mCD45⁺ cells in peripheral blood, spleen and bone marrow. The percentage of hCD19⁺hCD45⁺/mCD45⁺ cells represent B-ALL cells infiltrating in peripheral blood, spleen and bone marrow. The infiltration degree of B-ALL cells in bone marrow, spleen and peripheral blood of mice was different. Compared with PBS, CpG 685 could significantly inhibit the infiltration of B-ALL cells in bone marrow, spleen and peripheral blood, especially the infiltration of B-ALL cells in bone marrow (left panel). Aggregated results detected from 5 B-ALL PDX mice of each group and are presented as the mean ± SD (right panel). *p < 0.05, **p < 0.01. E Combination therapy with CpG 685 and imatinib prolonged the survival of Sup-B15 cell egraftment in NCG mouse xenograft models. Survival curve of Sup-B15 mice of each group (7 mice per group). F The percentage of hCD19⁺hCD34⁺/mCD45⁺ cells represent Sup-B15 cells infiltrating in peripheral blood, spleen and bone marrow. Although Sup-B15 was resistant to CpG 685 alone in vitro, CpG 685 could inhibit the infiltration of Sup-B15 cells in mouse bone marrow, spleen, and peripheral blood in vivo. Besides, combined application of imatinib and CpG 685 could significantly inhibit the infiltration of Sup-B15 cells in spleen and peripheral blood, especially in bone marrow. (left panel) Aggregated results detected from 5 Sup-B15 mice of each group and are presented as the mean ± SD (right panel). *p < 0.05, **p < 0.01