title: Mannan-binding lectin regulates dendritic cell maturation and cytokine production induced by lipopolysaccharide.
abstract: BACKGROUND
  Mannan-binding lectin (MBL) is a pattern-recognition molecule present in serum, which is involved in the innate immune defense by activating complement and promoting opsonophagocytosis. Dendritic cells (DCs) are professional antigen presenting cells (APCs) that are crucial for the initiation of adaptive immunity. Lipopolysaccharide (LPS) has been shown to be a strong activator of the inflammatory response and immune regulation. We first examined whether MBL modulated LPS-induced cellular responses, then investigated possible mechanisms of its inhibitory effect.
  
  
  RESULTS
  MBL at higher concentrations (10-20 μg/ml) significantly attenuated LPS-induced maturation of monocyte-derived DCs (MDCs) and production of proinflammatory cytokines (e.g., IL-12 and TNF-α), and inhibited their ability to activate allogeneic T lymphocytes. It bound to immature MDCs at physiological calcium concentrations, and was optimal at supraphysiological calcium concentrations. MBL also bound directly to immature MDCs and attenuated the binding of LPS to the cell surfaces, resulting in decreased LPS-induced nuclear factor-κB (NF-κB) activity in these cells.
  
  
  CONCLUSIONS
  All these data suggest that MBL could affect the functions of DCs by modifying LPS-induced cellular responses. This study supports an important role for MBL in the regulation of adaptive immune responses and inflammatory responses.
authors.affiliation: Department of Immunology, Southern Medical University, Guangzhou, 510515, PR China.
authors.forename: Mingyong
authors.initials: M
authors.lastname: Wang
authors.forename: Yani
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yue
authors.initials: Y
authors.lastname: Chen
authors.forename: Liyun
authors.initials: L
authors.lastname: Zhang
authors.forename: Xiao
authors.initials: X
authors.lastname: Lu
authors.forename: Zhengliang
authors.initials: Z
authors.lastname: Chen
mesh_terms: D015153:Blotting, Western; D002118:Calcium / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects; D016207:Cytokines / Q000096:biosynthesis*; D004247:DNA / Q000378:metabolism; D003713:Dendritic Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D018664:Interleukin-12 / Q000096:biosynthesis; D008070:Lipopolysaccharides / Q000494:pharmacology*; D037601:Mannose-Binding Lectin / Q000302:isolation & purification / Q000378:metabolism*; D009000:Monocytes / Q000166:cytology; D016328:NF-kappa B / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D021381:Protein Transport / Q000187:drug effects; D013601:T-Lymphocytes / Q000166:cytology / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
chemical_list: D016207:Cytokines; D008070:Lipopolysaccharides; D037601:Mannose-Binding Lectin; D016328:NF-kappa B; D014409:Tumor Necrosis Factor-alpha; D018664:Interleukin-12; D004247:DNA; D002118:Calcium