A synthetic hexapeptide with an acetylated amino terminus and an amidated carboxyl terminus that inhibits the binding of CXC chemokines to the chemokine receptor CXCR2; inhibits IL-8 binding to neutrophils (Ki = 2.7-13 µM), prevents neutrophil chemotaxis and β-glucuronidase release, and blocks IL-8-induced skin edema in rabbits.