Figure 4.

CD4- and CXCR4-mediated apoptosis does not involve G_iα activation. Binding of GTP[γ-³⁵S] to membranes of HPB-ALL cells and CD4⁺CXCR4⁺ transfectants was assayed in the absence (Ctrl) or presence of SDF-1 (200 nM), anti-CXCR4 (10 μg/ml), or anti-CD4 mAbs (10 μg/ml). The experiment shown was done in triplicate and is a representative of three experiments done.