Fig. 4.

The pseudo-(E)LR motif is crucial for the monocyte recruitment activity of MIF in vitro. (A) Effect on CXCR2-mediated monocyte arrest. HAoECs were preincubated with WT MIF, pseudo-(E)LR mutants, or buffer before the HAoEC monolayer was perfused with calcein AM-stained MonoMac6 cells. Adherent cells were quantified by counting multiple high-power fields; data (means ± SEM of 7 to 9 independent experiments) are represented as relative increase of adherent monocytes over control. (B) Effect on CXCR2-mediated monocyte chemotaxis. THP-1 monocytes were added to the upper compartment of a Transwell chamber and allowed to migrate in response to WT MIF or pseudo-(E)LR mutants in the lower chamber. The plot represents the chemotactic index at a protein concentration of 100 ng/ml. Data represent means ± SEM of 5 to 6 independent experiments.