title: Immune reactions of lymphocytes and macrophages against PEG-grafted pancreatic islets.
abstract: Graft rejection is the major limiting factor in islet transplantation and is closely related with the recruitment and activation of T cells and macrophages against the graft. To reduce the immunogenicity of islets, we have grafted biocompatible polyethylene glycol (PEG) onto the collagen capsule of islets without changing the morphology and function of islets. In this study, we evaluated whether the grafted PEG molecules on the collagen capsule of islet could prevent the activation of immune cells, and investigated factors that are mainly related to the immune reaction in vitro. During the co-culture with lymphocytes, the morphology and viability of PEG-grafted islets were not damaged, and the amounts of IL-2 and TNF-alpha secreted from lymphocytes co-cultured with PEG-grafted islets were significantly lower than that of free islets. However, when both kinds of islets were cultured with macrophages, there were no significant differences in morphology, viability and the secreted amounts of cytokines and nitric oxide. In conclusion, the grafted PEG could inhibit activation of lymphocytes, which are essential in initiating the graft rejection process. However, the grafted PEG molecules could not completely prevent the infiltration of cytotoxic molecules into the islets.
authors.affiliation: Department of Materials Science and Engineering, Kwangju Institute of Science and Technology, 1 Oryong-dong, Puk-gu, Gwangju 500-712, South Korea.
authors.forename: Ji Yeon
authors.initials: JY
authors.lastname: Jang
authors.forename: Dong Yun
authors.initials: DY
authors.lastname: Lee
authors.forename: Sang Jin
authors.initials: SJ
authors.lastname: Park
authors.forename: Youngro
authors.initials: Y
authors.lastname: Byun
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry; D018929:Cell Culture Techniques / Q000379:methods*; D002478:Cells, Cultured; D018920:Coculture Techniques / Q000379:methods; D006084:Graft Rejection / Q000276:immunology / Q000517:prevention & control; D007515:Islets of Langerhans / Q000276:immunology*; D016381:Islets of Langerhans Transplantation / Q000009:adverse effects / Q000276:immunology / Q000379:methods; D008213:Lymphocyte Activation / Q000276:immunology*; D008214:Lymphocytes / Q000276:immunology* / Q000473:pathology; D008264:Macrophages / Q000276:immunology* / Q000473:pathology; D008297:Male; D008422:Materials Testing; D011092:Polyethylene Glycols / Q000737:chemistry*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D001672:Biocompatible Materials; D011092:Polyethylene Glycols