title: CD4+CD25+Foxp3+IFN-γ+ human induced T regulatory cells are induced by interferon-γ and suppress alloresponses nonspecifically.
abstract: Interferon-γ (IFN-γ)-producing CD3(+)CD4(+)CD25(+)Foxp3(+) peripheral blood lymphocytes (PBL) are more frequently detectable in patients with good than in patients with impaired long-term kidney graft function, suggesting an immunoregulatory role of this induced T regulatory (iTreg) subtype. Herein, the in vitro function of separated CD3(+)CD4(+)CD25(+)Foxp3(+)IFN-γ(+) PBL that were induced by phorbol 12-myristate 13-acetate (PMA)/ionomycin or alloantigenic stimulation was investigated using cell coculture techniques and flow cytometry. CD4(+)CD25(+)Foxp3(+) PBL with intracellular IFN-γ production increased to 26% in cell cultures stimulated with PMA/ionomycin for 6 hours. Recombinant IFN-γ augmented and anti-IFN-γ monoclonal antibody blocked induction of CD4(+)CD25(+)Foxp3(+)IFN-γ(+) PBL, suggesting their IFN-γ-dependent induction. In addition, CD4(+)CD25(+)Foxp3(+)IFN-γ(+) PBL produced immunosuppressive interleukin (IL)-10, transforming growth factor-β, and IL-4 intracellularly and expressed both IFN-γ and IFN-γ receptors (CD119) on the cell surface, allowing separation of CD4(+)CD25(+)IFN-γ(+) PBL with 98% purity. Addition of enriched CD4(+)CD25(+)IFN-γ(+) PBL to autologous PMA/ionomycin stimulated PBL decreased blast formation (p < 0.05), indicating suppression of cell proliferation by CD4(+)CD25(+)IFN-γ(+) PBL. CD4(+)CD25(+)IFN-γ(+) PBL separated from primary mixed leukocyte cultures (MLC) and added to autologous or third-party secondary MLC suppressed allogeneic T-cell activation nonspecifically (p < 0.05). We conclude that CD4(+)CD25(+)Foxp3(+)IFN-γ(+) PBL are induced by IFN-γ, making them sensors for IFN-γ and initial immune responses. Circulating CD4(+)CD25(+)Foxp3(+)IFN-γ(+) PBL could suppress allogeneic T-cell responses in patients and may be involved in inhibition of the posttransplant alloresponse.
authors.affiliation: Department of Transplantation Immunology, Institute of Immunology, University of Heidelberg, Heidelberg, Germany. Volker.Daniel@med.uni-heidelberg.de
authors.forename: Volker
authors.initials: V
authors.lastname: Daniel
authors.forename: Mahmoud
authors.initials: M
authors.lastname: Sadeghi
authors.forename: Haihao
authors.initials: H
authors.lastname: Wang
authors.forename: Gerhard
authors.initials: G
authors.lastname: Opelz
mesh_terms: D015704:CD4 Antigens / Q000096:biosynthesis; D002469:Cell Separation; D002478:Cells, Cultured; D018920:Coculture Techniques; D005434:Flow Cytometry; D051858:Forkhead Transcription Factors / Q000096:biosynthesis; D006084:Graft Rejection / Q000276:immunology* / Q000517:prevention & control; D006706:Homeostasis; D006801:Humans; D007108:Immune Tolerance; D007371:Interferon-gamma / Q000276:immunology / Q000378:metabolism*; D053645:Interleukin-2 Receptor alpha Subunit / Q000096:biosynthesis; D007519:Isoantigens / Q000276:immunology*; D016030:Kidney Transplantation; D008213:Lymphocyte Activation; D037182:T-Cell Antigen Receptor Specificity / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D023001:Transplantation Tolerance
chemical_list: D015704:CD4 Antigens; C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; D053645:Interleukin-2 Receptor alpha Subunit; D007519:Isoantigens; D007371:Interferon-gamma