The transcription factor T-bet controls the Th1 genetic program in T cells for effective antitumor responses. Anti-CTLA-4 immunotherapy elicits dramatic antitumor responses in mice and in human patients; however, factors that regulate T-bet expression during an antitumor response mediated by anti-CTLA-4 remain to be elucidated. We were the first to report that treatment with anti-CTLA-4 led to ...

Previous mouse studies have shown that IL-4 increases the expression of ICOS on activated Th cells, resulting in enhanced ICOS expression on Th2 cells. In this study, we show that ICOS expression on human Th cells is not increased by IL-4, but by IL-12 and by IL-23 instead. Consequently, ICOS expression during IL-12-driven Th1 cell polarization was transiently increased compared with the levels...

The functions of NK cells are regulated by the balance of activating and inhibitory signals. The inhibitory NK cell receptors are well understood; however, less is known about the activating signaling pathways. To explore whether a costimulatory receptor, inducible costimulator (ICOS), is involved in NK cell function, we assessed the role of ICOS in NK cell-mediated cytotoxicity and cytokine pr...

Inducible co-stimulator (ICOS) is the third member of the CD28/cytotoxic T-lymphocyte associated antigen-4 family and is involved in the proliferation and activation of T cells. A detailed functional analysis of ICOS on peripheral blood T cells from patients with systemic lupus erythematosus (SLE) has not yet been reported. In the present study we developed a fully human anti-human ICOS mAb (JT...

The CD28 family molecules, CD28, and inducible costimulator (ICOS) all provide positive costimulatory signals. However, unlike CD28, ICOS does not costimulate IL-2 secretion. The YMNM motif that exists in the CD28 cytoplasmic domain is a known binding site for phosphatidylinositol 3-kinase (PI3-K) and Grb2. ICOS possesses the YMFM motif in the corresponding region of CD28 that binds PI3-K but n...

The anti-CTL-associated antigen 4 (anti-CTLA-4) antibody ipilimumab is the first agent to show improved survival in a randomized phase III trial that enrolled patients with metastatic melanoma. Studies are ongoing to identify mechanisms that elicit clinical benefit in the setting of anti-CTLA-4 therapy. We previously reported that treated patients had an increase in the frequency of T cells exp...

ICOS is an important regulator of T cell effector function. ICOS-deficient patients as well as knockout mice show severe defects in T cell-dependent B cell responses. Several in vitro and in vivo studies attributed this phenomenon to impaired up-regulation of cell surface communication molecules and cytokine synthesis by ICOS-deficient T cells. However, we now could show with Ag-specific T cell...

Background Inducible costimulator (ICOS) is rapidly upregulated with T-cell stimulation and may represent an escape pathway for T-cell costimulation in the setting of CD40/CD154 costimulation blockade. Induction treatment exhibited no efficacy in a primate renal allograft model, but rodent transplant models suggest that the addition of delayed ICOS/ICOS-L blockade may prolong allograft survival...

Vascular endothelial cells (ECs) and several cancer cells express B7h, which is the ligand of the ICOS T cell costimulatory molecule. We have previously shown that B7h triggering via a soluble form of ICOS (ICOS-Fc) inhibits the adhesion of polymorphonuclear and tumor cell lines to HUVECs; thus, we suggested that ICOS-Fc may act as an anti-inflammatory and antitumor agent. Because cancer cell m...

PURPOSE Inducible costimulator (ICOS) is an important costimulatory molecule involved in T-cell activation. In this study, the role of ICOS in the pathogenesis of uveitis in Behçet's disease (BD) was investigated. METHODS Peripheral blood mononuclear cells (PBMCs) were obtained from BD patients with uveitis in the active or remission phase and in healthy subjects. Total RNA was isolated from ...