Leukotriene B4 stimulates human polymorphonuclear leukocytes to synthesize and release interleukin-8 in vitro.
Interleukin-8 (IL-8) is a potent chemotactic protein for polymorphonuclear leukocytes (PMN). Here we examine whether PMN synthesize and release IL-8 in response to stimulation by leukotriene B4 (LTB4). PMN isolated from normal heparinized peripheral human blood were incubated in RPMI culture medium at 37 degrees C in 5% CO2, with and without LTB4. The culture supernatants were tested for IL-8 bioactivity through chemotactic activity measurements with and without neutralizing anti-IL-8 serum. Immunoreactive IL-8 was quantified by ELISA, and de novo IL-8 synthesis was evaluated by metabolic labeling with [35S]cysteine followed by immunoprecipitation. LTB4 stimulated PMN to produce IL-8 in a dose- and time-dependent manner. The IL-8 concentrations reached maximal levels after 16 h of incubation with LTB4. Significant increases in IL-8 production occurred with LTB4 doses of 10 to 1,000 nM/ml. Immunoprecipitation of labeled IL-8 documented new synthesis of IL-8 by LTB4-treated PMN. Northern blot analysis of total RNA from PMN using a 30 mer oligonucleotide for IL-8 demonstrated increased mRNA expression in LTB4-stimulated PMN compared with untreated PMN. These data show that peripheral blood PMN can be stimulated by LTB4 to synthesize and secrete biologically active IL-8. PMN and other cells capable of producing LTB4 may induce IL-8 protein production by inflammatory PMN and thereby amplify or perpetuate the acute inflammatory response by recruiting additional PMN into an inflammatory site.
McCain
R W
RW
Department of Veterans Affairs, Nashville, Tennessee.
Holden
E P
EP
Blackwell
T R
TR
Christman
J W
JW
D000906:Antibodies; D001483:Base Sequence; D002478:Cells, Cultured; D002634:Chemotaxis, Leukocyte; D006801:Humans; D016209:Interleukin-8 / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology; D007975:Leukotriene B4 / Q000494:pharmacology*; D008969:Molecular Sequence Data; D009500:Neutralization Tests; D009504:Neutrophils / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D014158:Transcription, Genetic / Q000187:drug effects
D000906:Antibodies; D016209:Interleukin-8; D012333:RNA, Messenger; D007975:Leukotriene B4