Migratory response to N-terminal truncated CXCL12(3-68). Chemotaxis assays using Sca-1⁺c-kit⁺lin^— mBM cells (A) and Sca-1⁺c-kit⁺lin^— mBM cells (B) were performed comparing the normal CXCL12 and the N-terminal truncated form CXCL12(3-68). (A) CXCL12 induced a normal dose-dependent migratory response in Sca-1⁺c-kit⁺lin^— mBM cells (•). CXCL12(3-68) did not induce the migration of cells compared with CXCL12 (▪, P < .01, n = 8). Preincubation of cells for 15 minutes with CXCL12(3-68) (100 ng/mL) inhibits the normal CXCL12-induced migration of cells (▴, P = .04, n = 8). (B) CXCL12 again induced a normal dose-dependent migratory response in Sca-1⁺c-kit^—lin^— mBM cells (•). CXCL12(3-68) did not induce the migration of cells compared with CXCL12 (▪, P < .01, n = 8). Preincubation of cells for 15 minutes with CXCL12(3-68) (100 ng/mL) inhibits the normal CXCL12-induced migration of cells (▴, P = .02, n = 8). Error bars represent SEMs.