title: Autocrine activation-induced cell death of T cells by human peripheral blood monocyte-derived CD4+ dendritic cells.
abstract: Mature T cells activated by antigen (Ag)-presenting cells are subject to various downmodulatory processes designed to maintain T cell homeostasis. Here we describe experiments in which mature T cells were subjected to apoptosis following stimulation with CD4(+) dendritic cells (DCs) during Ag presentation. The proliferative response of allogeneic T cells was increased by DCs at stimulator to responder (S/R) ratios ranging from 10(-3) to 1, whereas this response was decreased at S/R ratios ranging from 2 to 10. Allogeneic T cells stimulated with DCs at an S/R ratio of 5 underwent apoptosis, whereas this event was not observed in allogeneic T cells stimulated with DCs at an S/R ratio of 0.5. Stimulation of T cells with DCs at an S/R ratio of 5 induced a higher level of expression of CD95 ligand (CD95L) than stimulation of T cells cultured with DCs at an S/R ratio of 0.5, whereas similar levels of expression of CD28 and CD154 were observed in both cells. The abortive proliferation of mature T cells stimulated with DCs was prevented by blocking the CD95-CD95L system. Our results suggest that the CD4(+) DCs play counterregulatory roles in dictating T cell responses during Ag presentation.
authors.affiliation: Department of Cell Processing, The University of Tokyo, Tokyo, 108-8639, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Sato
authors.forename: H
authors.initials: H
authors.lastname: Nagayama
authors.forename: M
authors.initials: M
authors.lastname: Enomoto
authors.forename: K
authors.initials: K
authors.lastname: Tadokoro
authors.forename: T
authors.initials: T
authors.lastname: Juji
authors.forename: T A
authors.initials: TA
authors.lastname: Takahashi
mesh_terms: D017951:Antigen Presentation / Q000276:immunology; D017209:Apoptosis / Q000276:immunology*; D019898:Autocrine Communication / Q000276:immunology*; D015704:CD4 Antigens / Q000096:biosynthesis*; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000276:immunology* / Q000378:metabolism; D015536:Down-Regulation / Q000276:immunology; D053222:Fas Ligand Protein; D006801:Humans; D016130:Immunophenotyping; D008024:Ligands; D008213:Lymphocyte Activation / Q000276:immunology; D008562:Membrane Glycoproteins / Q000502:physiology; D009000:Monocytes / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*; D019014:fas Receptor / Q000502:physiology
chemical_list: D015704:CD4 Antigens; C505661:FASLG protein, human; D053222:Fas Ligand Protein; D008024:Ligands; D008562:Membrane Glycoproteins; D019014:fas Receptor