Many chemokines including CCL20/MIP-3α display antimicrobial activity

Previous studies have demonstrated that β‐defensins exhibit chemotactic activity by sharing the chemokine receptor CCR6 with the CC chemokine ligand CCL20/macrophage‐inflammatory protein‐3α (MIP‐3α). Structural analysis of CCL20/MIP‐3α revealed that most of the positively charged residues are concentrated at one area of its topological surface, a characteristic considered to be important for the antimicrobial activity of defensins. Here, we report that similar to defensins, CCL20/MIP‐3α has antimicrobial effects on Escherichia coli, Pseudomonas aeruginosa, Moraxella catarrhalis, Streptococcus pyogenes, Enterococcus faecium, Staphylococcus aureus, and Candida albicans. Additionally, by screening a total of 30 human chemokines, we have identified an additional 17 human chemokines, which exhibit antimicrobial activity in vitro. Collectively, about two‐thirds of the chemokines investigated so far has the capacity to kill microorganisms in vitro, suggesting that antimicrobial activity may be another host‐defense function for certain chemokines. Comparison of the structural characteristics between antimicrobial and nonantimicrobial chemokines suggests that topological formation of a large, positively charged electrostatic patch on the surface of the molecule is likely to be a common structural feature of antimicrobial chemokines.