title: Improved coating of pancreatic islets with regulatory T cells to create local immunosuppression by using the biotin-polyethylene glycol-succinimidyl valeric acid ester molecule.
abstract: BACKGROUND
  We showed that T regulatory (Treg) cells can be attached to the surface of pancreatic islets providing local immunoprotection. Further optimization of the method can improve coating efficiency, which may prolong graft survival. In this study, we compared the effectiveness of two different molecules used for binding of the Tregs to the surface of pancreatic islets. Our aim was to increase the number of Treg cells attached to islets without compromising islets viability and function.
  
  
  METHODS
  The cell surface of human Treg cells and pancreatic islets was modified using biotin-polyethylene glycol-N-hydroxylsuccinimide (biotin-PEG-NHS) or biotin-PEG-succinimidyl valeric acid ester (biotin-PEG-SVA). Then, islets were incubated with streptavidin as islet/Treg cells binding molecule. Treg cells were stained with CellTracker CM-DiL dye and visualized using a Laser Scanning Confocal Microscope. The number of Treg cells attached per islets surface area was analyzed by Imaris software. The effect of coating on islet functionality was determined using the glucose-stimulated insulin response (GSIR) assay.
  
  
  RESULTS
  The coating procedure with biotin-PEG-SVA allowed for attaching 40% more Treg cells per 1 μm(2) of islet surface. Although viability was comparable, function of the islets after coating using the biotin-PEG-SVA molecule was better preserved than with NHS molecule. GSIR was 62% higher for islets coated with biotin-PEG-SVA compared to biotin-PEG-NHS.
  
  
  CONCLUSIONS
  Coating of islets with Treg cells using biotin-PEG-SVA improves effectiveness with better preservation of the islet function. Improvement of the method of coating pancreatic islets with Treg cells could further facilitate the effectiveness of this novel immunoprotective approach and translation into clinical settings.
authors.affiliation: Department of Surgery, The University of Chicago, Chicago, IL, USA.
authors.forename: K
authors.initials: K
authors.lastname: Gołąb
authors.affiliation: Department of Chemical and Biological Engineering, College of Engineering, Koç University, Istanbul, Turkey.
authors.forename: S
authors.initials: S
authors.lastname: Kizilel
authors.affiliation: Department of Chemical and Biological Engineering, College of Engineering, Koç University, Istanbul, Turkey.
authors.forename: T
authors.initials: T
authors.lastname: Bal
authors.affiliation: Department of Medicine, University of Chicago, Chicago, IL, USA.
authors.forename: M
authors.initials: M
authors.lastname: Hara
authors.affiliation: Department of Medicine, University of Chicago, Chicago, IL, USA.
authors.forename: M
authors.initials: M
authors.lastname: Zielinski
authors.affiliation: Department of Surgery, The University of Chicago, Chicago, IL, USA.
authors.forename: R
authors.initials: R
authors.lastname: Grose
authors.affiliation: Department of Surgery, The University of Chicago, Chicago, IL, USA.
authors.forename: O
authors.initials: O
authors.lastname: Savari
authors.affiliation: Department of Surgery, The University of Chicago, Chicago, IL, USA.
authors.forename: X-J
authors.initials: XJ
authors.lastname: Wang
authors.affiliation: Department of Surgery, The University of Chicago, Chicago, IL, USA.
authors.forename: L-J
authors.initials: LJ
authors.lastname: Wang
authors.affiliation: Department of Surgery, The University of Chicago, Chicago, IL, USA.
authors.forename: M
authors.initials: M
authors.lastname: Tibudan
authors.affiliation: Department of Clinical Immunology and Transplantology, Medical University of Gdansk, Gdansk, Poland.
authors.forename: A
authors.initials: A
authors.lastname: Krzystyniak
authors.affiliation: Department of Clinical Immunology and Transplantology, Medical University of Gdansk, Gdansk, Poland.
authors.forename: N
authors.initials: N
authors.lastname: Marek-Trzonkowska
authors.affiliation: Department of Surgery, The University of Chicago, Chicago, IL, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Millis
authors.affiliation: Department of Clinical Immunology and Transplantology, Medical University of Gdansk, Gdansk, Poland.
authors.forename: P
authors.initials: P
authors.lastname: Trzonkowski
authors.affiliation: Department of Surgery, The University of Chicago, Chicago, IL, USA. Electronic address: pwitkowski@surgery.bsd.uchicago.edu.
authors.forename: P
authors.initials: P
authors.lastname: Witkowski
mesh_terms: D000818:Animals; D001710:Biotin; D002232:Carbocyanines; D002448:Cell Adhesion / Q000502:physiology; D006801:Humans; D007165:Immunosuppression Therapy; D007515:Islets of Langerhans / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D010421:Pentanoic Acids; D011092:Polyethylene Glycols; D019809:Streptavidin; D013388:Succinimides; D013501:Surface-Active Agents; D050378:T-Lymphocytes, Regulatory / Q000502:physiology*; D046509:Tissue Culture Techniques; D014022:Tissue Survival
chemical_list: C434385:3,3'-dioactadecyl-5,5'-di(4-sulfophenyl)oxacarbocyanine; D002232:Carbocyanines; D010421:Pentanoic Acids; D013388:Succinimides; D013501:Surface-Active Agents; D011092:Polyethylene Glycols; D001710:Biotin; D019809:Streptavidin; C038780:n-pentanoic acid