title: Functional interaction of cockroach allergens and mannose receptor (CD206) in human circulating fibrocytes.
abstract: BACKGROUND
  The innate pattern recognition C-type-lectin receptors (CLRs), including mannose receptor (MRC1; CD206), have been suggested to functionally interact with allergens and are critical in controlling immune response. Fibrocytes have been considered to play a role in allergic asthma. Here we sought to investigate the functional interaction of cockroach allergens with CD206 in fibrocytes.
  
  
  METHODS
  Profiling of N-linked glycans from natural purified cockroach allergen Bla g 2 was accomplished by MALDI-MS. The binding activity of cockroach allergens to CD206 was determined by solid-phase binding assays. Levels of CD206 expression on human fibrocytes and CD206 mediated signaling and cytokine production in Bla g 2 treated fibrocytes were determined.
  
  
  RESULTS
  Profiling of N-linked glycans from Bla g 2 revealed a predominance of small, mannose-terminated glycans with and without fucose. Significant binding of Bla g 2 to CD206 was observed, which was inhibited by yeast mannan (a known CD206 ligand), free mannose, and a blocking antibody (anti-hMR). Flow cytometric analyses of human fibrocytes (CD45(+) and collagen-1(+)) showed selective expression of CD206 on fibrocytes. Functionally, a concentration-dependent uptake of FITC labeled Bla g 2 by fibrocytes was observed, but was significantly inhibited by anti-hMR. Bla g 2 can stimulate up-regulation of inflammatory cytokines including TNF-alpha and IL-6 and activation of nuclear factor kappa B (NF-kB/p65), p38 mitogen-activated protein kinase (p38), ERK, and JNK in cultured fibrocytes. This increased secretion of TNF-alpha and IL-6 and activation of NF-kB, ERK, and JNK was significantly inhibited by the addition of either mannan or mannose. Furthermore, Bla g 2 induced increase in TNF-alpha and IL-6 production was also inhibited by the use of NF-kB, ERK, and JNK inhibitors.
  
  
  CONCLUSIONS
  These results provide evidence supporting the existence of a functional cockroach allergen-CD206 axis in human fibrocytes, suggesting a role for CD206 in regulating allergen induced allergic responses in asthma.
authors.affiliation: Johns Hopkins Asthma and Allergy Center, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
authors.forename: Ying-Ming
authors.initials: YM
authors.lastname: Tsai
authors.forename: Shih-Chang
authors.initials: SC
authors.lastname: Hsu
authors.forename: Jian
authors.initials: J
authors.lastname: Zhang
authors.forename: Yu-Feng
authors.initials: YF
authors.lastname: Zhou
authors.forename: Beverly
authors.initials: B
authors.lastname: Plunkett
authors.forename: Shau-Ku
authors.initials: SK
authors.lastname: Huang
authors.forename: Pei-Song
authors.initials: PS
authors.lastname: Gao
mesh_terms: D000485:Allergens / Q000276:immunology* / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D016282:Aspartic Acid Endopeptidases / Q000276:immunology / Q000378:metabolism / Q000494:pharmacology; D015153:Blotting, Western; D002478:Cells, Cultured; D003058:Cockroaches / Q000276:immunology* / Q000378:metabolism; D016207:Cytokines / Q000276:immunology / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D006801:Humans; D037181:Lectins, C-Type / Q000276:immunology* / Q000378:metabolism; D008351:Mannans / Q000378:metabolism / Q000494:pharmacology; D008358:Mannose / Q000378:metabolism / Q000494:pharmacology; D000090323:Mannose Receptor; D037241:Mannose-Binding Lectins / Q000276:immunology* / Q000378:metabolism; D059630:Mesenchymal Stem Cells / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000276:immunology / Q000378:metabolism; D011134:Polysaccharides / Q000276:immunology / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects / Q000276:immunology; D011956:Receptors, Cell Surface / Q000276:immunology* / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D051996:Transcription Factor RelA / Q000276:immunology / Q000378:metabolism
chemical_list: D000485:Allergens; D016207:Cytokines; D037181:Lectins, C-Type; D008351:Mannans; D000090323:Mannose Receptor; D037241:Mannose-Binding Lectins; D011134:Polysaccharides; D011956:Receptors, Cell Surface; D051996:Transcription Factor RelA; D020928:Mitogen-Activated Protein Kinases; D016282:Aspartic Acid Endopeptidases; C094699:allergen Bla g 2; D008358:Mannose