Fig. 4. FcγRIIb mediates malignant BTK activation in Bcr-Abl-positive cells.
a Western blot analyses of immortalized FcγRIIb+/+ and FcγRIIb−/− Bcr-Abl and ev (empty vector) BM cells were performed using the indicated antibodies. b FcγRIIb was retrovirally introduced into FcγRIIb−/−:Bcr-Abl cells and protein lysates were analyzed for BTK and ERK1/2 activation. c CFU assay using FcγRIIb+/+:ev, FcγRIIb−/−:ev, FcγRIIb+/+:Bcr-Abl, FcγRIIb−/−:Bcr-Abl, or FcγRIIb−/−:Bcr-Abl:FcγRIIb cells. Colony numbers were counted 7 days after seeding. Data are shown as mean ± SD. **p < 0.001 and ***p < 0.0001.