title: Monophosphoryl lipid A-induced pro-inflammatory cytokine expression does not require CD14 in primary human dendritic cells.
abstract: OBJECTIVE
  To elucidate if TLR4-mediated MyD88 and TRIF signalling by the clinically applicable Lipopolysaccharide (LPS)-derivative monophosphoryl lipid A (MPLA) in primary human dendritic cells requires LPS cofactors LPS-binding protein (LBP) and CD14.
  
  
  METHODS
  Cytokine production by monocyte-derived DCs stimulated with MPLA or LPS was determined using ELISA. To investigate involvement of CD14 for action of LPS or MPLA, CD14 was inhibited using blocking antibodies or down-modulated using specific siRNA. To assess involvement of LBP monocyte-derived DCs were stimulated in serum-free culture medium in absence or presence of purified LBP.
  
  
  RESULTS
  LBP and CD14 are not required for and do not enhance the capacity of MPLA to induce MyD88- and TRIF-dependent pro-inflammatory IL-6 and TNF-α. Interestingly, although CD14 is required for TRIF-dependent downstream events in mice, we show that in human CD14 is redundant for MPLA-induced TRIF-dependent chemokine production.
  
  
  CONCLUSIONS
  These findings provide novel insight in the modes of action of MPLA in human and show that, compared to LPS, MyD88 and TRIF signalling in dendritic cells by MPLA is not mediated nor amplified by TLR4 cofactors. This gives insight why MPLA induces immune activation without provoking toxicity in human and clarifies why MPLA can be used as activating compound for clinically applicable immuno-activatory cellular products grown in serum-free regimens.
authors.affiliation: Division Research and Landsteiner Laboratory, Sanquin Blood Supply, Department of Immunopathology, Academic Medical Center, University of Amsterdam, P.O. Box 9190, 1006 AD, Amsterdam, The Netherlands.
authors.forename: Sonja T H M
authors.initials: ST
authors.lastname: Kolanowski
authors.affiliation: Division Research and Landsteiner Laboratory, Sanquin Blood Supply, Department of Immunopathology, Academic Medical Center, University of Amsterdam, P.O. Box 9190, 1006 AD, Amsterdam, The Netherlands.
authors.forename: Suzanne N
authors.initials: SN
authors.lastname: Lissenberg-Thunnissen
authors.affiliation: Division Research and Landsteiner Laboratory, Sanquin Blood Supply, Department of Immunopathology, Academic Medical Center, University of Amsterdam, P.O. Box 9190, 1006 AD, Amsterdam, The Netherlands.
authors.forename: Diba
authors.initials: D
authors.lastname: Emal
authors.affiliation: Division Research and Landsteiner Laboratory, Sanquin Blood Supply, Department of Immunopathology, Academic Medical Center, University of Amsterdam, P.O. Box 9190, 1006 AD, Amsterdam, The Netherlands.|Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: S Marieke
authors.initials: SM
authors.lastname: van Ham
authors.affiliation: Division Research and Landsteiner Laboratory, Sanquin Blood Supply, Department of Immunopathology, Academic Medical Center, University of Amsterdam, P.O. Box 9190, 1006 AD, Amsterdam, The Netherlands. a.tenbrinke@sanquin.nl.
authors.forename: Anja
authors.initials: A
authors.lastname: Ten Brinke
mesh_terms: D000209:Acute-Phase Proteins / Q000378:metabolism; D033942:Adaptor Proteins, Vesicular Transport / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism*; D003713:Dendritic Cells / Q000187:drug effects* / Q000378:metabolism; D015536:Down-Regulation; D006801:Humans; D008050:Lipid A / Q000031:analogs & derivatives* / Q000494:pharmacology; D018950:Lipopolysaccharide Receptors / Q000235:genetics / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D008562:Membrane Glycoproteins / Q000378:metabolism; D053594:Myeloid Differentiation Factor 88 / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects; D000099231:Lipopolysaccharide-Binding Protein
chemical_list: D000209:Acute-Phase Proteins; D033942:Adaptor Proteins, Vesicular Transport; D002352:Carrier Proteins; D016207:Cytokines; D008050:Lipid A; D018950:Lipopolysaccharide Receptors; D008070:Lipopolysaccharides; D008562:Membrane Glycoproteins; D053594:Myeloid Differentiation Factor 88; D034741:RNA, Small Interfering; D000099231:Lipopolysaccharide-Binding Protein; C507779:MYD88 protein, human; C470409:TICAM1 protein, human; C048436:monophosphoryl lipid A
keywords: Adjuvants; LBP; MyD88; TLR4; Vaccine