Figure 5. IL-20 inhibits neutrophil migration in vitro.

(A) 1.5×10⁶ peripheral blood neutrophils were placed in the upper chamber of transwell plates. After 3 hours, the number of cells that migrated across the transwell insert to lower chambers was counted using a hemacytometer. The lower chambers contained media or supernatants from human bronchial epithelial (BEAS2b) cells that had been infected with S. aureus (MOI 2) for 4 hours, sterile-filtered, and then subjected to immunoprecipitation with isotype control or IL-20 antibody. Under some conditions (αIL-20+IL-20), recombinant IL-20 (10 ng/mL) was added back to supernatant after IL-20 immunoprecipitation. (B) Neutrophils were treated with indicated inhibitors and stimulated to migrate across a transwell chamber as in (A). (C) Neutrophils untreated or treated with indicated inhibitors and stimulated to migrate across transwell inserts for 1 hour to wells containing S. aureus (2×10⁶ CFU/well) + IL-8 (100 ng/mL) alone or with IL-20 (10 ng/mL). (D) Western blot of lysates from neutrophils, untreated or treated with indicated inhibitors, infected with S. aureus (MOI 1) and stimulated with IL-8 alone or with IL-20 for 10 minutes. For A–C, data shown reflect mean +/− SEM of results from three donors, and *p<0.05, **p<0.01 by t test.