α6 blockade sensitizes leukemia cells to chemotherapy in vivo. (A) The treatment regimen used in NSG mice injected with primary B-ALL cells (LAX7R) consisted of the intraperitoneal administration of PBS (n = 5); an α6-blocking Ab (P5G10) (n = 5) (administered intraperitoneally on days 3, 10, 17, and 24 after leukemia injection as indicated by the red triangles); vincristine (10.5 mg/kg), dexamethasone (8 mg/kg), and L-asparaginase (800 IU/kg) (VDL) (n = 5) (as indicated by the gray rectangles); or VDL + P5G10 (n = 5). (B) The Kaplan-Meier survival curve was analyzed, and the MST was calculated for each group: PBS (MST = 39 days), P5G10 (MST = 31 days), VDL (MST = 71 days), VDL + P5G10 (MST = 185 days). (C) Bioluminescence imaging of mice on days 66, 92, 147, and 186 after leukemia cell transfer. A mouse with no leukemia cell injection treated only with luciferin at the time of imaging was included as a background control (Image Ctrl) (right panel). One experiment is shown. (D) Flow cytometric analysis of human (h) CD19 and murine (m) CD45 in BM mononuclear cells (MNCs) from 3 animals euthanized on day 186 after injection or found dead (FD) on day 185 after injection.