Treatment with an anti-CD14 monoclonal antibody delays and inhibits lipopolysaccharide-induced gene expression in humans in vivo.
CD14 is a receptor important for activation of cells by lipopolysaccharide (LPS). Treatment with the CD14 antibody IC14 was previously found to attenuate the release of proinflammatory cytokines and some chemokines into the circulation of healthy humans intravenously injected with LPS. To determine the role of circulating leukocytes in CD14-dependent gene expression, 16 healthy volunteers received LPS preceded by either IC14 or placebo. At different time points, mRNA was isolated from whole blood and gene expression was determined by multiplex ligation-dependent probe amplification (MLPA). LPS induced MIP-1alpha, MIP-1beta, IL-8, IL-1beta, and IL-1Ra mRNA production, which was delayed by 1 hr and reduced twofold by IC14 treatment. TNFR1 was unresponsive, whereas other investigated cytokines remained undetectable. Further, LPS showed differential effects on NFkappaB gene expression. LPS induced IkappaBalpha production, whereas p50 was unresponsive and p65 and p49/p100 remained undetectable. LPS induced IkappaBalpha expression was delayed (1 hr) and reduced by IC14. Gene expression profiles in blood cells corresponded poorly with observed changes in plasma levels. These data suggest that peripheral blood cells are of negligible importance in LPS-induced production of inflammatory mediators in vivo and that LPS may activate genes via a CD14-independent pathway that is slower and less efficient.
Spek
C Arnold
CA
Laboratory for Experimental Internal Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands. c.a.spek@amc.uva.nl
Verbon
Annelies
A
Aberson
Hella
H
Pribble
John P
JP
McElgunn
Cathal J
CJ
Turner
Terence
T
Axtelle
Tim
T
Schouten
Jan
J
Van Der Poll
Tom
T
Reitsma
Pieter H
PH
D000328:Adult; D000911:Antibodies, Monoclonal / Q000494:pharmacology*; D016207:Cytokines / Q000235:genetics; D020869:Gene Expression Profiling / Q000379:methods; D005786:Gene Expression Regulation / Q000187:drug effects*; D006801:Humans; D007962:Leukocytes / Q000502:physiology; D018950:Lipopolysaccharide Receptors / Q000276:immunology / Q000502:physiology*; D008070:Lipopolysaccharides / Q000494:pharmacology; D016328:NF-kappa B / Q000235:genetics; D021141:Nucleic Acid Amplification Techniques / Q000379:methods; D012333:RNA, Messenger / Q000032:analysis
D000911:Antibodies, Monoclonal; D016207:Cytokines; D018950:Lipopolysaccharide Receptors; D008070:Lipopolysaccharides; D016328:NF-kappa B; D012333:RNA, Messenger