Il-8((3-73))K11R is a high affinity agonist of the neutrophil CXCR1 and CXCR2.
In studies aimed at developing a high affinity IL-8 antagonist, our first objective was to generate a high-affinity IL-8 analogue. We targeted amino acids within the receptor-binding domain and found that IL-8((3-73))K11R induced significantly more neutrophil beta-glucuronidase release than either IL-8 or the alternate analogues and, in chemotaxis assays, induced 2-3-fold greater neutrophil responses than IL-8. Furthermore, in competitive radio- or biotinylated-ligand binding assays, IL-8((3-73))K11R was more effective than IL-8, IL-8((3-73)), or its T12S, H13F, and K11R/T12S/H13F analogues in blocking IL-8 binding to neutrophils; 1.8 pmol IL-8((3-73))K11R inhibited by 50% the binding of approximately 20 pmol (125)I-IL-8 to neutrophils. Both IL-8 (a CXCR1/CXCR2 ligand) and the CXCR2-specific ligand GROalpha differentially inhibited binding of (125)I-IL-8((3-73))K11R to neutrophils, albeit weakly, suggesting that IL-8((3-73))K11R is a high affinity ligand for both the CXCR1 and CXCR2. Thus IL-8((3-73))K11R is an excellent candidate for further studies aimed at generating a high affinity IL-8 antagonist.
Li
F
F
Department of Veterinary Microbiology, University of Saskatchewan, Saskatoon, S7N 5B4, Canada.
Gordon
J R
JR
D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D002633:Chemotaxis; D016209:Interleukin-8 / Q000031:analogs & derivatives* / Q000235:genetics; D008969:Molecular Sequence Data; D018375:Neutrophil Activation; D009504:Neutrophils / Q000276:immunology*; D010455:Peptides / Q000494:pharmacology; D023062:Receptors, Interleukin-8A / Q000378:metabolism*; D023063:Receptors, Interleukin-8B / Q000378:metabolism*
D016209:Interleukin-8; D010455:Peptides; D023062:Receptors, Interleukin-8A; D023063:Receptors, Interleukin-8B