Figure 3.

The CXC chemokine ligand 12 (CXCL12)–CXCR4 axis mediates chronic lymphocytic leukemia (CLL)-induced T-cell suppression. T cells were cocultured with CLL cells at a 1:10 ratio for 48 h, with or without 250 ng/ml CXCL12. The T cells were then isolated and stimulated with anti-CD3/CD28 beads for 6 h and stained for IFNγ, TNFα, IL-2, and CD107a. The addition of CXCL12 to the coculture induced T cell dysfunction by the CLL cells. Blocking mAbs to CXCR4 inhibited CXCL12–CLL-induced suppression of T cells (n = 6). FACS plots are gated on live CD3+ cells.