title: Chemokine (C-C Motif) Receptor 2 Mediates Dendritic Cell Recruitment to the Human Colon but Is Not Responsible for Differences Observed in Dendritic Cell Subsets, Phenotype, and Function Between the Proximal and Distal Colon.
abstract: OBJECTIVE
  Most knowledge about gastrointestinal (GI)-tract dendritic cells (DC) relies on murine studies where CD103+DC specialize in generating immune tolerance with the functionality of CD11b+/-subsets being unclear. Information about human GI-DC is scarce, especially regarding regional specifications. Here, we characterized human DC properties throughout the human colon.
  
  
  METHODS
  Paired proximal (right/ascending) and distal (left/descending) human colonic biopsies from 95 healthy subjects were taken; DC were assessed by flow cytometry and microbiota composition assessed by 16S rRNA gene sequencing.
  
  
  RESULTS
  Colonic DC identified were myeloid (mDC, CD11c+CD123-) and further divided based on CD103 and SIRPα (human analog of murine CD11b) expression. CD103-SIRPα+DC were the major population and with CD103+SIRPα+DC were CD1c+ILT3+CCR2+(although CCR2 was not expressed on all CD103+SIRPα+DC). CD103+SIRPα-DC constituted a minor subset that were CD141+ILT3-CCR2-. Proximal colon samples had higher total DC counts and fewer CD103+SIRPα+cells. Proximal colon DC were more mature than distal DC with higher stimulatory capacity for CD4+CD45RA+T-cells. However, DC and DC-invoked T-cell expression of mucosal homing markers (β7, CCR9) was lower for proximal DC. CCR2 was expressed on circulating CD1c+, but not CD141+mDC, and mediated DC recruitment by colonic culture supernatants in transwell assays. Proximal colon DC produced higher levels of cytokines. Mucosal microbiota profiling showed a lower microbiota load in the proximal colon, but with no differences in microbiota composition between compartments.
  
  
  CONCLUSIONS
  Proximal colonic DC subsets differ from those in distal colon and are more mature. Targeted immunotherapy using DC in T-cell mediated GI tract inflammation may therefore need to reflect this immune compartmentalization.
authors: Antigen Presentation Research Group, Imperial College London, Harrow, United Kingdom.
authors: David
authors: D
authors: Bernardo
authors: Antigen Presentation Research Group, Imperial College London, Harrow, United Kingdom.
authors: Lydia
authors: L
authors: Durant
authors: Antigen Presentation Research Group, Imperial College London, Harrow, United Kingdom; Centre for Immunobiology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom.
authors: Elizabeth R
authors: ER
authors: Mann
authors: Gut Health and Food Safety Programme, Institute of Food Research, Norwich, United Kingdom.
authors: Elizabeth
authors: E
authors: Bassity
authors: Mucosal Immunology Group, Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid-CSIC, Valladolid, Spain.
authors: Enrique
authors: E
authors: Montalvillo
authors: St. Mark's Hospital, North West London Hospitals NHS Trust, Harrow, United Kingdom.
authors: Ripple
authors: R
authors: Man
authors: Antigen Presentation Research Group, Imperial College London, Harrow, United Kingdom; St. Mark's Hospital, North West London Hospitals NHS Trust, Harrow, United Kingdom.
authors: Rakesh
authors: R
authors: Vora
authors: Antigen Presentation Research Group, Imperial College London, Harrow, United Kingdom.
authors: Durga
authors: D
authors: Reddi
authors: Department of Physiology, Faculty of Medicine, Yildirim Beyazit University, Ankara, Turkey; Faculty of Farmacy, Agri İbrahim Cecen University, Agri, Turkey.
authors: Fahri
authors: F
authors: Bayiroglu
authors: Gastroenterology Service, Hospital Clínico Universitario de Valladolid, Valladolid, Spain.
authors: Luis
authors: L
authors: Fernández-Salazar
authors: Antigen Presentation Research Group, Imperial College London, Harrow, United Kingdom.
authors: Nick R
authors: NR
authors: English
authors: Antigen Presentation Research Group, Imperial College London, Harrow, United Kingdom; St. Mark's Hospital, North West London Hospitals NHS Trust, Harrow, United Kingdom.
authors: Simon T C
authors: ST
authors: Peake
authors: Antigen Presentation Research Group, Imperial College London, Harrow, United Kingdom; St. Mark's Hospital, North West London Hospitals NHS Trust, Harrow, United Kingdom.
authors: Jon
authors: J
authors: Landy
authors: Antigen Presentation Research Group, Imperial College London, Harrow, United Kingdom; St. Mark's Hospital, North West London Hospitals NHS Trust, Harrow, United Kingdom.
authors: Gui H
authors: GH
authors: Lee
authors: Antigen Presentation Research Group, Imperial College London, Harrow, United Kingdom; St. Mark's Hospital, North West London Hospitals NHS Trust, Harrow, United Kingdom.
authors: George
authors: G
authors: Malietzis
authors: Antigen Presentation Research Group, Imperial College London, Harrow, United Kingdom; St. Mark's Hospital, North West London Hospitals NHS Trust, Harrow, United Kingdom.
authors: Yi Harn
authors: YH
authors: Siaw
authors: Antigen Presentation Research Group, Imperial College London, Harrow, United Kingdom; St. Mark's Hospital, North West London Hospitals NHS Trust, Harrow, United Kingdom.
authors: Aravinth U
authors: AU
authors: Murugananthan
authors: Antigen Presentation Research Group, Imperial College London, Harrow, United Kingdom; St. Mark's Hospital, North West London Hospitals NHS Trust, Harrow, United Kingdom.
authors: Phil
authors: P
authors: Hendy
authors: Antigen Presentation Research Group, Imperial College London, Harrow, United Kingdom.
authors: Eva
authors: E
authors: Sánchez-Recio
authors: St. Mark's Hospital, North West London Hospitals NHS Trust, Harrow, United Kingdom.
authors: Robin K S
authors: RK
authors: Phillips
authors: Mucosal Immunology Group, Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid-CSIC, Valladolid, Spain; Genetics and Molecular Biology Department, Clinical Laboratory Service, Hospital Universitario Rio Hortega, Valladolid, Spain.
authors: Jose A
authors: JA
authors: Garrote
authors: Pathogen Genomics Group, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridgeshire, United Kingdom.
authors: Paul
authors: P
authors: Scott
authors: Pathogen Genomics Group, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridgeshire, United Kingdom.
authors: Julian
authors: J
authors: Parkhill
authors: National Heart and Lung Institute, Imperial College London, London.
authors: Malte
authors: M
authors: Paulsen
authors: St. Mark's Hospital, North West London Hospitals NHS Trust, Harrow, United Kingdom.
authors: Ailsa L
authors: AL
authors: Hart
authors: Antigen Presentation Research Group, Imperial College London, Harrow, United Kingdom.
authors: Hafid O
authors: HO
authors: Al-Hassi
authors: St. Mark's Hospital, North West London Hospitals NHS Trust, Harrow, United Kingdom.
authors: Eduardo
authors: E
authors: Arranz
authors: Pathogen Genomics Group, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridgeshire, United Kingdom; Microbiology Group, Rowett Institute of Nutrition and Health, University of Aberdeen, Aberdeen, United Kingdom.
authors: Alan W
authors: AW
authors: Walker
authors: Gut Health and Food Safety Programme, Institute of Food Research, Norwich, United Kingdom; Norwich Medical School, University of East Anglia, Norwich, United Kingdom.
authors: Simon R
authors: SR
authors: Carding
authors: Antigen Presentation Research Group, Imperial College London, Harrow, United Kingdom.
authors: Stella C
authors: SC
authors: Knight
keywords: AMOVA, analysis of molecular variance; CCL, chemokine (C-C motif) ligand; CCR, chemokine (C-C motif) receptor; CCR2; CFSE, 5-carboxy fluorescein diacetate succinimidyl ester; DC, dendritic cells; DL, detection limit; Dendritic Cells; Distal Colon; FACS, fluorescence-activated cell sorting; FITC, fluorescein isothiocyanate; GI, gastrointestinal; Human Gastrointestinal Tract; IL, interleukin; ILT3, Ig-like transcript 3; LPMC, lamina propria mononuclear cells; Microbiota; Mφ, macrophages; PBMC, peripheral blood mononuclear cells; PCR, polymerase chain reaction; Proximal Colon; RALDH2, retinaldehyde dehydrogenase type 2; SIRPα, signal regulatory protein α; SPB, sodium phosphate buffer; Treg, regulatory T-cells; mDC, myeloid dendritic cell; pDC, plasmacytoid dendritic cell