title: Bone marrow-derived dendritic cells reverse the anergic state of CD4+CD25+ T cells without reversing their suppressive function.
abstract: Dendritic cells (DC) are potent inducers of immunity to foreign Ags, but also contribute to self-tolerance by induction of regulatory T cells or deletion/anergy of self-reactive T cells. In this study, we have studied the capacity of DC to activate naturally occurring CD4+CD25+ regulatory T cells as well as the ability of CD4+CD25+ T cells to suppress the DC-mediated activation of CD4+CD25- T cells. Mature bone marrow-derived dendritic cells, but not splenic DC, were able to induce the proliferation of CD4+CD25+ T cells in the presence of a polyclonal stimulus and in the absence of exogenous IL-2. The DC-induced proliferative response of the CD4+CD25+ T cells was partially dependent on IL-2 produced by a small number of contaminating CD25+ effector cells. Because bone marrow-derived dendritic cells induce proliferation of both CD4+CD25+ and CD4+CD25- T cells in vitro, it was impossible to assay the suppressive function of the CD4+CD25+ T cells using [3H]TdR uptake or CFSE dilution. We therefore measured IL-2 production in cocultures of CD4+CD25+ and CD4+CD25- T cells using the IL-2 secretion assay. Surprisingly, CD4+CD25+ T cells markedly suppressed IL-2 secretion by the CD4+CD25- T cells without inhibiting their proliferation. Collectively, these results suggest that Ag presentation by DC can induce the expansion of CD4+CD25+ T cells while simultaneously activating their ability to suppress cytokine secretion by effector T cells.
authors.affiliation: Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Carine
authors.initials: C
authors.lastname: Brinster
authors.forename: Ethan M
authors.initials: EM
authors.lastname: Shevach
mesh_terms: D000818:Animals; D017951:Antigen Presentation / Q000276:immunology; D001854:Bone Marrow Cells / Q000166:cytology* / Q000276:immunology; D015704:CD4 Antigens / Q000276:immunology / Q000378:metabolism; D049109:Cell Proliferation; D017635:Clonal Anergy / Q000276:immunology*; D018920:Coculture Techniques; D003713:Dendritic Cells / Q000276:immunology* / Q000378:metabolism; D005260:Female; D005434:Flow Cytometry; D007376:Interleukin-2 / Q000096:biosynthesis / Q000276:immunology / Q000378:metabolism; D008213:Lymphocyte Activation / Q000276:immunology*; D051379:Mice; D020297:Mice, Congenic; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D015375:Receptors, Interleukin-2 / Q000276:immunology / Q000378:metabolism; D013154:Spleen / Q000166:cytology / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology* / Q000378:metabolism
chemical_list: D015704:CD4 Antigens; D007376:Interleukin-2; D015375:Receptors, Interleukin-2