Project description:The role of ICOS in anti-tumor T cell responses and overall tumor progression has been controversial. Here, we compared tumor progression in mice lacking ICOS only in Treg cells or in all T cells. We found that Treg-specific ICOS knockout reduces the overall tumor burden compared to Cre control mice with increased T effector/Treg ratios in the tumor. In contrast, there was no difference in the tumor burden in mice lacking ICOS in all the T cell compartments. This suggests a dual role of ICOS costimulation in promoting pro- and anti-tumor T cell responses. Consistent with reduced tumor burden, we found that Treg-specific deletion of ICOS leads to an increase of CD8+ CTLs that express high levels of granzyme B and perforin. Moreover, single-cell transcriptome analysis revealed an increase of Ly108hiEomeshi CD8+ T cell subset at the cost of Ly108hiT-bethi subset in Treg-specific knockout mice. These results suggest that ICOS-expressing Treg cells suppress CTL maturation process at the level of Eomes upregulation, a critical step known to drive perforin expression and cytotoxicity. Collectively, our data imply that cancer immunotherapies using ICOS agonist antibodies would work better in Treg-low tumors or when they are combined with regimens that deplete tumor-infiltrating Treg cells.
Project description:ICOS is induced in activated T cells and its main role is to boost differentiation and function of effector T cells. ICOS is also constitutively expressed in a subpopulation of Foxp3+ regulatory T cells under steady-state condition. Studies using ICOS germline knockout mice or ICOS-blocking reagents suggested that ICOS has supportive roles in regulatory T (Treg) cell homeostasis, migration, and function. To avoid any compounding effects that may arise from ICOS-deficient non-Treg cells, we generated a conditional knockout system in which ICOS expression is selectively abrogated in Foxp3-expressing cells (ICOS FC mice). Compared to Foxp3-Cre control mice, ICOS FC mice showed a minor numerical deficit of steady-state Treg cells but did not show any signs of spontaneous autoimmunity, indicating that tissue-protective Treg populations do not heavily rely on ICOS costimulation. However, ICOS FC mice showed more severe inflammation in oxazolone-induced contact hypersensitivity, a model of atopic dermatitis. This correlated with elevated numbers of inflammatory T cells expressing IFN-γ and/or TNF-α in ICOS FC mice compared with the control group. In contrast, elimination of ICOS in all T cell compartments negated the differences, confirming that ICOS has a dual positive role in effector and Treg cells. Single-cell transcriptome analysis suggested that ICOS-deficient Treg cells fail to mature into T-bet+CXCR3+ “Th1-Treg” cells in the draining lymph node. Our results suggest that regimens that preferentially stimulate ICOS pathways in Treg cells might be beneficial for the treatment of Th1-driven inflammation.
Project description:ICOS (Inducible Costimulator) is a T cell costimulatory molecule. We found that the cloned T-cell hybridoma 6-13-64 consists of two populations, ICOS expressing and non-expressing. The aim of this study is to screen for candidate genes that regulate ICOS gene expression by transcriptional profiling and comparison of the ICOS-positive and ICOS-negative subpopulations isolated from the 6-13-64 T-cell hybridoma. One-condition experiment, ICOS(-) vs. ICOS(+) cells. Independently grown and harvested. One replicate per array.
Project description:ICOS (Inducible Costimulator) is a T cell costimulatory molecule. We found that the cloned T-cell hybridoma 6-13-64 consists of two populations, ICOS expressing and non-expressing. The aim of this study is to screen for candidate genes that regulate ICOS gene expression by transcriptional profiling and comparison of the ICOS-positive and ICOS-negative subpopulations isolated from the 6-13-64 T-cell hybridoma.
Project description:ICOS is a T cell costimulatory receptor critical for Tfh cell generation and function. However, the role of ICOS in Tfr cell differentiation remains unclear. Using Foxp3-Cre-mediated ICOS knockout (ICOS FC) mice, we show that ICOS deficiency in Treg-lineage cells drastically reduces the number of Tfr cells during GC reactions but has a minimal impact on conventional Treg cells. Single-cell transcriptome analysis of Foxp3+ cells at an early stage of the GC reaction suggests that ICOS normally inhibits Klf2 expression to promote follicular features including Bcl6 upregulation. Further, ICOS costimulation promotes nuclear localization of NFAT2, a known driver of CXCR5 expression. Notably, ICOS FC mice had an unaltered overall GC B cell output but showed signs of expanded autoreactive B cells along with elevated autoantibody titers. Thus, our study demonstrates that ICOS costimulation is critical for Tfr cell differentiation and highlights the importance of Tfr cells in maintaining humoral immune tolerance during GC reactions.
Project description:Analysis of TH17 cells redirected with chimeric antigen receptors (CAR) expressing various signaling domains (including CD28, 4-1BB and ICOS) after surrogate antigen stimulation. Our results showed that T cells redirected with an ICOS-based CAR specifically retained a genotype of TH17 cells with expression of Il17a, Il17f, Il1r1, Ccl20, Rorc, and in the absence of Foxp3
Project description:Analysis of TH17 cells redirected with chimeric antigen receptors (CAR) expressing various signaling domains (including CD28, 4-1BB and ICOS) after surrogate antigen stimulation. Our results showed that T cells redirected with an ICOS-based CAR specifically retained a genotype of TH17 cells with expression of Il17a, Il17f, Il1r1, Ccl20, Rorc, and in the absence of Foxp3 CAR-redirected TH17 cells from three different human normal donors were stimulated with immobilized recombinant mesothelin. Gene expression levels were determined prior to stimulation (day 0) and 4, 8, 24 and 96 hours upon antigen recognition.
Project description:Co-stimulatory molecules of the CD28 family on T lymphocytes integrate cues from innate immune system sensors, and modulate activation responses in conventional CD4+ T cells (Tconv) and their FoxP3+ regulatory counterparts (Treg). To better understand how costimulatory and co-inhibitory signals might be integrated, we profiled the changes in gene expression elicited in the hours and days after engagement of Treg and Tconv by anti-CD3 and either anti-CD28, -CTLA4, -ICOS, -PD1, -BTLA or -CD80. Total CD4+ T cells were stimulated by anti-CD3 and either anti-CD28, -CTLA4, -ICOS, -PD1, -BTLA or -CD80 antibodies for 1, 4, 20 and 48 hrs and Tconv and Treg were separated by flowcytometry. The 1 and 4 hr lysates were pooled [the 'early' samples] before RNA purification and profiling, as were the 20 and 48 hr samples [the 'late' samples] (note; for Treg cells, only the 20 hr sample was used). RNA was amplified, labeled and hybridized to Mouse Gene 1.0 ST arrays with the data generation and quality control pipeline of 19 the Immunological Genome Project (www.immgen.org), in biological triplicates (duplicates only for ICOS and CD80). Raw data were background-corrected and normalized using the RMA algorithm.
Project description:Gene expression analysis of WT and IL-2Ra-deficient CTL (P14) isolated 8 days after inffection with LCMV. The goals of the study are to assess the impact of IL-2 signals on effector and memory CTL differentiation.