IL-8 causes in vivo neutrophil migration by a cell-dependent mechanism.
A dose-dependent neutrophil migration was observed following the injection of recombinant interleukin-8 (rIL-8) into rat peritoneal cavities. This finding contrasts with the inability of rIL-8 to induce neutrophil emigration into subcutaneous air-pouches. Pre-treatment of the animals with dexamethasone (0.5 mg/kg, s.c.) or depletion of the peritoneal resident cell population abolished the neutrophil migration induced by rIL-8 and by recombinant interleukin-1 beta (rIL-1 beta). Different from that which occurs with rIL-1 beta, neutrophil migration induced by rIL-8 was not enhanced by an increase in the peritoneal macrophage population. Transference of homologous total resident peritoneal cells to the air-pouch rendered this cavity responsive to the chemotactic effect of rIL-8 and potentiated the neutrophil migration induced by rIL-1. Our results show that both rIL-8 and rIL-1 beta are able to induce in vivo neutrophil migration by an indirect mechanism, dependent on resident cells. Neither macrophages nor lymphocytes seem to be involved in the rIL-8 chemotactic effect. However, peritoneal resident mast cells may be implicated in this mechanism. These cells, when stimulated in vitro by rIL-8, released a factor that when injected into peritoneal and air-pouch cavities induced neutrophil migration.
Departamento de Farmacologia, Faculdade de Medicina de Ribeirão Preto, Brasil.
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D000818:Animals; D002634:Chemotaxis, Leukocyte / Q000187:drug effects / Q000276:immunology*; D003907:Dexamethasone / Q000494:pharmacology; D007375:Interleukin-1 / Q000276:immunology; D016209:Interleukin-8 / Q000276:immunology*; D008297:Male; D008407:Mast Cells / Q000276:immunology; D009504:Neutrophils / Q000276:immunology*; D010529:Peritoneal Cavity / Q000166:cytology; D010533:Peritoneal Lavage; D051381:Rats; D011919:Rats, Inbred Strains; D011994:Recombinant Proteins / Q000276:immunology; D013864:Thioglycolates / Q000494:pharmacology
D007375:Interleukin-1; D016209:Interleukin-8; D011994:Recombinant Proteins; D013864:Thioglycolates; D003907:Dexamethasone