Fetal mononuclear cells show a comparable capacity with maternal mononuclear cells to produce IL-8 in response to lipopolysaccharide in chorioamnionitis.
IL-8 is a chemotactic and activating cytokine for neutrophils which eliminate invading bacteria by releasing bactericidal metabolites. Cord blood mononuclear cells (CBMCs) obtained from neonates born to mothers with chorioamnionitis actively produced a significantly higher amount of IL-8 than those of neonates without chorioamnionitis, suggesting that the mononuclear cells of fetuses with chorioamnionitis had been activated in utero. As lipopolysaccharide (LPS) can often be detected in the uteroplacental space in chorioamnionitis, the LPS-mediated activation mechanism of neonatal mononuclear cells was analyzed in vitro to produce IL-8. Neonatal mononuclear cells stimulated with LPS increased IL-8 production in a time- and dose-dependent manner. The ability of term or preterm neonatal mononuclear cells to produce IL-8 was comparable with that of adult (maternal) mononuclear cells, suggesting functional maturity of the neonatal or fetal mononuclear cells to produce IL-8. However, IL-8 production by neonatal CBMCs was down-regulated by dexamethasone, a glucocorticoid which is clinically administered to mothers to promote fetal lung maturity in preterm delivery. Our present study revealed a regulatory mechanism of fetal IL-8 production, suggesting that functionally mature fetal mononuclear cells produce IL-8 in response to LPS in chorioamnionitis and activate the fetal defense mechanism against infection.
Taniguchi
T
T
Department of Obstetrics and Gynecology, Osaka University Medical School, Japan.
Matsuzaki
N
N
Shimoya
K
K
Neki
R
R
Okada
T
T
Kitajima
H
H
Saji
F
F
Tanizawa
O
O
D002478:Cells, Cultured; D002821:Chorioamnionitis / Q000276:immunology*; D003907:Dexamethasone / Q000494:pharmacology; D004306:Dose-Response Relationship, Immunologic; D005260:Female; D005312:Fetal Blood / Q000166:cytology*; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D007231:Infant, Newborn; D016209:Interleukin-8 / Q000096:biosynthesis*; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000276:immunology*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D011247:Pregnancy / Q000097:blood*; D013997:Time Factors
D016209:Interleukin-8; D008070:Lipopolysaccharides; D003907:Dexamethasone