title: Ethylenecarbodiimide-coupled allogeneic antigen presenting cells induce human CD4+ regulatory T cells.
abstract: Adoptive transfer of naturally occurring CD4(+)CD25(+) regulatory T cells can tolerize transplantation alloresponses in animal models. However isolation of these cells in sufficient numbers from humans is cumbersome and prone to contamination with alloreactive CD25(+) T cells. Incubation of ethylenecarbodiimide-coupled antigen presenting cells (APC) with naïve T cells and antigen has been shown to induce tolerance in various experimental models. We therefore investigated whether ECDI-coupled allogeneic APC were able to induce an expandable human CD4(+) Treg population. CD4(+) and CD4(+) CD25(-) cells cultured for 5 days with ECDI-treated human PBMC exhibited potent suppressive capacity in a mixed lymphocyte reaction. Induction of these ECDI-Tregs was associated with up-regulation of Foxp3 mRNA and protein expression and they maintained high expression of CD62L and CD27 as well as low CD127 expression. ECDI-treated APC displayed reduced expression of the co-stimulatory signaling molecules CD40 and CD80, and failed to stimulate proliferation and cytokine secretion in co-cultured CD4(+) T cells. Restimulation in the presence of rapamycin and hrIL-2 led to expansion of ECDI-Tregs with increasing Foxp3 levels and suppressive activity significantly higher than expanded naturally occurring CD4(+)CD25(+) Tregs. In summary these findings support the hypothesis that ECDI-coupled APC can convert naïve CD4(+) T cells into functional Tregs with different phenotypic characteristics than naturally occurring CD4(+)CD25(+) Tregs. These inducible Tregs could provide a novel approach that might facilitate the translation of ex vivo generated and expanded Tregs into clinical settings.
authors.affiliation: Department of Pediatric Hematology/Oncology, Dr. von Haunersches Children's Hospital, Ludwig-Maximilians-University, Lindwurmstr. 4, 80337 Munich, Germany. michael.albert@med.uni-muenchen.de
authors.forename: Michael H
authors.initials: MH
authors.lastname: Albert
authors.forename: Xue-Zhong
authors.initials: XZ
authors.lastname: Yu
authors.forename: Thomas
authors.initials: T
authors.lastname: Magg
mesh_terms: D000938:Antigen-Presenting Cells / Q000187:drug effects / Q000276:immunology*; D002234:Carbodiimides / Q000494:pharmacology*; D018920:Coculture Techniques; D016207:Cytokines / Q000276:immunology; D005434:Flow Cytometry; D051858:Forkhead Transcription Factors / Q000096:biosynthesis / Q000235:genetics; D006801:Humans; D007108:Immune Tolerance / Q000276:immunology; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000276:immunology; D007959:Lymphocyte Culture Test, Mixed; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D020123:Sirolimus / Q000494:pharmacology; D050378:T-Lymphocytes, Regulatory / Q000187:drug effects / Q000276:immunology* / Q000502:physiology; D015854:Up-Regulation
chemical_list: D002234:Carbodiimides; D016207:Cytokines; C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; D012333:RNA, Messenger; D020123:Sirolimus