title: Differential susceptibility of human T(h)1 versus T(h) 2 cells to induction of anergy and apoptosis by ECDI/antigen-coupled antigen-presenting cells.
abstract: Antigen-coupled antigen-presenting cells (APC) serve as potent tolerogens for inhibiting immune responses in vivo and in vitro, apparently by providing an antigen-specific signal through the TCR in the absence of co-stimulation. Although this approach has been well studied in rodents, little is known about its effects on human T cells. We evaluated the specificity and mechanisms of tolerization of human T cells in vitro using monocyte-enriched adherent cells that were pulsed with antigen and treated with the cross-linker, 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (ECDI). Autologous antigen-coupled APC selectively tolerized T cells of the T(h)1 but not T(h)2 lineage through a mechanism that involved both antigen-specific and antigen-non-specific elements. The tolerization process was dependent on the ECDI and antigen concentration, and the coupling time, and was reflected by initial up-regulation of CD25. However, upon re-stimulation with fresh APC and antigen, tolerized T(h)1 cells failed to proliferate or to produce T(h)1 cytokine message or secreted protein, had decreased expression of CD25, CD28 and B7 and increased expression of MHC class II molecules, and demonstrated an enhanced commitment to apoptosis. T(h)1 cell tolerization could be prevented by adding anti-CD28 antibody, IL-2 or untreated APC at the same time as the ECDI/antigen-coupled APC, or reversed by adding anti-CD28 antibody or IL-2 upon re-stimulation with fresh APC plus antigen. Thus, the tolerizing effect of ECDI/antigen-coupled APC on human T(h)1 cells appears to involve a reversible anergy mechanism leading to apoptosis, whereby the targeted T cells receive full or partial activation through the TCR, without coordinate co-stimulation. These data suggest dichotomous signaling requirements for inactivating cells of the T(h)1 and T(h)2 lineages that may have important implications for treatment of T(h)1-mediated autoimmune or inflammatory diseases.
authors.affiliation: Neuroimmunology Research R & D-31, Veterans Affairs Medical Center, Portland, OR 97201, USA. Sc.
authors.forename: A A
authors.initials: AA
authors.lastname: Vandenbark
authors.forename: D
authors.initials: D
authors.lastname: Barnes
authors.forename: T
authors.initials: T
authors.lastname: Finn
authors.forename: D N
authors.initials: DN
authors.lastname: Bourdette
authors.forename: R
authors.initials: R
authors.lastname: Whitham
authors.forename: I
authors.initials: I
authors.lastname: Robey
authors.forename: J
authors.initials: J
authors.lastname: Kaleeba
authors.forename: B F
authors.initials: BF
authors.lastname: Bebo
authors.forename: S D
authors.initials: SD
authors.lastname: Miller
authors.forename: H
authors.initials: H
authors.lastname: Offner
authors.forename: Y K
authors.initials: YK
authors.lastname: Chou
mesh_terms: D017951:Antigen Presentation; D000938:Antigen-Presenting Cells / Q000276:immunology*; D017209:Apoptosis; D018106:CD28 Antigens / Q000276:immunology; D017635:Clonal Anergy; D003432:Cross-Linking Reagents; D005022:Ethyldimethylaminopropyl Carbodiimide; D006801:Humans; D016753:Interleukin-10 / Q000096:biosynthesis / Q000235:genetics; D007376:Interleukin-2 / Q000276:immunology; D015848:Interleukin-5 / Q000096:biosynthesis / Q000235:genetics; D009103:Multiple Sclerosis / Q000276:immunology; D004676:Myelin Basic Protein / Q000276:immunology; D011948:Receptors, Antigen, T-Cell; D015398:Signal Transduction; D018139:Simplexvirus / Q000276:immunology; D013745:Tetanus Toxoid / Q000276:immunology; D018417:Th1 Cells / Q000276:immunology*; D018418:Th2 Cells / Q000276:immunology*
chemical_list: D018106:CD28 Antigens; D003432:Cross-Linking Reagents; D007376:Interleukin-2; D015848:Interleukin-5; D004676:Myelin Basic Protein; D011948:Receptors, Antigen, T-Cell; D013745:Tetanus Toxoid; D016753:Interleukin-10; D005022:Ethyldimethylaminopropyl Carbodiimide