Fig. 2

CXCL11 and CXCL12 synergistically promote migration of A549 and A767 cells. To define whether CXCL11 and CXCL12 additively or synergistically affect cell migration, chemotactic responses of A549 and A767 cells were determined in the presence of a constant concentration of one chemokine (10 ng/ml) and increasing concentrations of the respective other chemokine (1 ng/ml – 100 ng/ml). Migration index was assessed as described in Fig. 1. Data represent average migration index (+SD) as determined in 4–10 experiments. Addition of the respective other chemokine at concentrations as low as 1 ng/ml already increased migration by 1.6-fold to 2.3-fold, indicative for synergistic effects of chemokines on cell migration