CXCL8((3-73))K11R/G31P antagonizes the neutrophil chemoattractants present in pasteurellosis and mastitis lesions and abrogates neutrophil influx into intradermal endotoxin challenge sites in vivo.
The ELR(+) CXC chemokines are critical for protective neutrophil responses to most bacterial infections, but nevertheless can contribute importantly to the pathogenic effects of many inflammatory responses. We recently engineered a series of high affinity CXCL8/IL-8 antagonists, one of which, CXCL8((3-73))K11R/G31P, binds very strongly to neutrophils via the CXCR1 and CXCR2. Herein we show in competitive 125I-ligand binding assays that bovine CXCL8((3-73))K11R/G31P has an affinity for neutrophils that is 2-3 orders of magnitude higher than that of CXCL8/IL-8. Furthermore, when used at approximately 0.5 nM, CXCL8((3-73))K11R/G31P inhibited by 50% the chemotactic responses of neutrophils to 129 nM CXCL8/IL-8, but it also blocked chemotactic responses to the alternate ELR-CXC chemokines CXCL1/GRO alpha and CXCL5/ENA-78. Furthermore, CXCL8((3-73))K11R/G31P could inhibit by 93-97% the spectrum of neutrophil chemotactic activities present within wash fluids from clinical bacterial pneumonia or experimental endotoxin-induced mastitis lesions. Finally, intramuscular or subcutaneous application of CXCL8((3-73))K11R/G31P (75 micro g/kg) reduced by up to 97% neutrophil infiltration into intradermal endotoxin challenge sites in cattle, and prevented their circulating neutrophils from responding to CXCL8/IL-8 or ENA-78 in vitro. This data thus encourages further investigation of the potential impact of this novel antagonist on ELR-CXC chemokine-driven inflammatory disorders.
Li
Fang
F
Department of Veterinary Microbiology, University of Saskatchewan, SK, S7N 5B4, Saskatoon, Canada.
Zhang
Xiaobei
X
Mizzi
Chris
C
Gordon
John R
JR
D000818:Animals; D002417:Cattle; D019743:Chemokines, CXC / Q000494:pharmacology*; D002630:Chemotactic Factors / Q000037:antagonists & inhibitors* / Q000276:immunology / Q000302:isolation & purification; D002634:Chemotaxis, Leukocyte / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004731:Endotoxins / Q000008:administration & dosage / Q000276:immunology*; D016209:Interleukin-8 / Q000276:immunology; D008414:Mastitis, Bovine / Q000276:immunology*; D009504:Neutrophils / Q000166:cytology / Q000187:drug effects*; D012766:Pasteurellosis, Pneumonic / Q000276:immunology*; D010446:Peptide Fragments / Q000494:pharmacology*; D012882:Skin Tests / Q000662:veterinary; D013997:Time Factors
C457773:CXCL8(3-73)K11R,G31P, bovine; D019743:Chemokines, CXC; D002630:Chemotactic Factors; D004731:Endotoxins; D016209:Interleukin-8; D010446:Peptide Fragments