Discloses an antibody which binds to CXC chemokine receptor (4) (CXCR4) and which do not induce significant apoptosis of CXCR4 expressing cells, wherein levels of apoptosis induced in the presence of the antibody are comparable or not significantly different from levels of apoptosis induced in the absence of the antibody, and wherein said antibody is capable of inhibiting the binding of a ligand to CXCR4 or is capable of inhibiting the ligand-induced migration of CXCR4 expressing cells, or is capable of inhibiting ligand-induced calcium flux in CXCR4 expressing cells and wherein the ligand is SDF-1. Further discloses the use of said antibody in the manufacture of a medicament for treating a disease associated with CXCR4 expression or activity (such as cancer).
