title: Pancreatic islets engineered with SA-FasL protein establish robust localized tolerance by inducing regulatory T cells in mice.
abstract: Allogeneic islet transplantation is an important therapeutic approach for the treatment of type 1 diabetes. Clinical application of this approach, however, is severely curtailed by allograft rejection primarily initiated by pathogenic effector T cells regardless of chronic use of immunosuppression. Given the role of Fas-mediated signaling in regulating effector T cell responses, we tested if pancreatic islets can be engineered ex vivo to display on their surface an apoptotic form of Fas ligand protein chimeric with streptavidin (SA-FasL) and whether such engineered islets induce tolerance in allogeneic hosts. Islets were modified with biotin following efficient engineering with SA-FasL protein that persisted on the surface of islets for >1 wk in vitro. SA-FasL-engineered islet grafts established euglycemia in chemically diabetic syngeneic mice indefinitely, demonstrating functionality and lack of acute toxicity. Most importantly, the transplantation of SA-FasL-engineered BALB/c islet grafts in conjunction with a short course of rapamycin treatment resulted in robust localized tolerance in 100% of C57BL/6 recipients. Tolerance was initiated and maintained by CD4(+)CD25(+)Foxp3(+) regulatory T (Treg) cells, as their depletion early during tolerance induction or late after established tolerance resulted in prompt graft rejection. Furthermore, Treg cells sorted from graft-draining lymph nodes, but not spleen, of long-term graft recipients prevented the rejection of unmodified allogeneic islets in an adoptive transfer model, further confirming the Treg role in established tolerance. Engineering islets ex vivo in a rapid and efficient manner to display on their surface immunomodulatory proteins represents a novel, safe, and clinically applicable approach with important implications for the treatment of type 1 diabetes.
authors: Institute for Cellular Therapeutics, University of Louisville, Louisville, KY 40202, USA.
authors: Esma S
authors: ES
authors: Yolcu
authors: Hong
authors: H
authors: Zhao
authors: Laura
authors: L
authors: Bandura-Morgan
authors: Chantale
authors: C
authors: Lacelle
authors: Kyle B
authors: KB
authors: Woodward
authors: Nadir
authors: N
authors: Askenasy
authors: Haval
authors: H
authors: Shirwan
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D003922:Diabetes Mellitus, Type 1 / Q000276:immunology / Q000601:surgery; D053222:Fas Ligand Protein / Q000276:immunology*; D006084:Graft Rejection / Q000276:immunology / Q000517:prevention & control; D007108:Immune Tolerance / Q000276:immunology*; D007150:Immunohistochemistry; D007202:Indicators and Reagents; D007515:Islets of Langerhans / Q000276:immunology*; D016381:Islets of Langerhans Transplantation / Q000276:immunology* / Q000379:methods; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D011993:Recombinant Fusion Proteins / Q000276:immunology*; D019809:Streptavidin / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D014184:Transplantation, Homologous
chemical_list: D053222:Fas Ligand Protein; D007202:Indicators and Reagents; D011993:Recombinant Fusion Proteins; D019809:Streptavidin