scholarly journals 711 HBM1022, a novel anti-CCR8 antibody depletes tumor-infiltrating regulatory T cells via enhanced ADCC activity, mediates potent anti-tumor activity with Keytruda

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A753-A753
Author(s):  
Shuang Lu ◽  
Shaoping Hu ◽  
Xin Gan ◽  
Yongqiang Wang ◽  
Chuchu Zhao ◽  
...  
Keyword(s):  
Breast Cancer ◽  
T Cells ◽  
Regulatory T Cells ◽  
Treg Cells ◽  
Functional Assay ◽  
List Type ◽  
Adcc Activity ◽  
Dependent Cell ◽  
Tumor Types

BackgroundCCR8-expressing CD4 and Foxp3 positive Treg (CCR8+ Treg) has been demonstrated to be a major driver for immunosuppression in solid tumors1 <1> Superscript. Clinical studies have shown that CCR8 is selectively up-regulated by tumor resident Tregs in several tumor types including clear cell renal cell carcinoma (ccRCC)2 <2> Superscript and breast cancer3 <3> Superscript. In these tumor types, CCR8 exhibit strong expression on tumor resident Tregs while it is rarely observed on Tregs in peripheral blood mononuclear cells (PBMCs). High expression of the CCR8 in tumor-infiltrating lymphocytes-Treg cells (TIL-Tregs) was associated with poor prognosis in breast cancer patients. These results suggest CCR8 as a promising therapeutic target; and anti-CCR8 mAbs could selectively inhibit a subpopulation of tumor resident Tregs in the tumor microenvironment (TME), to augment antitumor immunity.MethodsIn vitro assay:HBM1022 binding on human, cynomolgus CCR8 and TIL-Tregs are evaluated via flow cytometry. Blocking and ADCC functional assay are all based on CCR8 overexpressing cell lines.In vivo efficacy study:HBM1022 anti-CCR8 antibody was administered after implantation (≈ 100 mm3 <3>Superscript tumor volume) alone and in combination with anti−PD-1.ResultsAnti-CCR8 antibody HBM1022 specifically binds to cell lines that over-express human or cynomolgus CCR8, as well as TIL-Tregs in multiple cancer types with the high affinity. HBM1022 potently blocks CCL1 binding to both human and cynomolgus CCR8. HBM1022 inhibits CCL1-induced migration and related GPCR signaling pathways. Furthermore, with enhanced antibody-dependent cell-mediated cytotoxicity (eADCC) activity, HBM1022 exhibits potent in vitro killing activity on CCR8-expressing cells. HBM1022 shows tumor growth inhibition as monotherapy in preclinical mouse syngeneic and humanized models. Moreover, HBM1022 shows enhanced antitumor activity with the combination of Keytruda® in preclinical efficacy models.ConclusionsOur finding reveals HBM1022 as an innovative immunotherapy targeting intra-tumoral suppressive Treg cells to change suppressive tumor to hot tumor. HBM1022 presents its great potential as exciting mono or combo anti-tumor therapies.ReferencesYiftah B, Gizi W, Eran L, et al. CCR8+FOXp3+ Treg cells as master drivers of immune regulation. Proc Natl Acad Sci U S A 2017;114 (23):6086–6091.Tetsuya Y, Yujiro K, Mitsunobu M, et al. Method of treating cancer with an anti-CCR8 having antibody-dependent cell-mediated cytotoxicity (ADCC) activity against cells expressing CCR8. US10550191B2. 2020.George P, Catherine K, Kenmin W, et al. Regulatory T cells exhibit distinct features in human breast cancer. Immunity 2016;45:1122–1134.

scholarly journals Trichostatin A Promotes the Generation and Suppressive Functions of Regulatory T Cells

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Cristian Doñas ◽  
Macarena Fritz ◽  
Valeria Manríquez ◽  
Gabriela Tejón ◽  
María Rosa Bono ◽  
...  
Keyword(s):  
T Cells ◽  
Regulatory T Cells ◽  
Trichostatin A ◽  
Gene Promoter ◽  
Treg Cells ◽  
Specific Subset ◽  
Global Increase ◽  
And Function ◽  
H3 Acetylation

Regulatory T cells are a specific subset of lymphocytes that suppress immune responses and play a crucial role in the maintenance of self-tolerance. They can be generated in the thymus as well as in the periphery through differentiation of naïve CD4+T cells. The forkhead box P3 transcription factor (Foxp3) is a crucial molecule regulating the generation and function of Tregs. Here we show that thefoxp3gene promoter becomes hyperacetylated inin vitrodifferentiated Tregs compared to naïve CD4+T cells. We also show that the histone deacetylase inhibitor TSA stimulated thein vitrodifferentiation of naïve CD4+T cells into Tregs and that this induction was accompanied by a global increase in histone H3 acetylation. Importantly, we also demonstrated that Tregs generated in the presence of TSA have phenotypical and functional differences from the Tregs generated in the absence of TSA. Thus, TSA-generated Tregs showed increased suppressive activities, which could potentially be explained by a mechanism involving the ectonucleotidases CD39 and CD73. Our data show that TSA could potentially be used to enhance the differentiation and suppressive function of CD4+Foxp3+Treg cells.

scholarly journals P01.02 TLR-mediated suppression of the CCL22-CCR4 axis as a new target for tumor immunotherapy

2021 ◽  
Vol 9 (Suppl 1) ◽  
pp. A3.2-A4
Author(s):  
J Grün ◽  
I Piseddu ◽  
C Perleberg ◽  
N Röhrle ◽  
S Endres ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
B Cells ◽  
Regulatory T Cells ◽  
Type I ◽  
List Type ◽  
Gm Csf

BackgroundUnmethylated CpG-DNA is a potent ligand for the endosomal Toll-like-receptor-9, important for the immune activation to pathogen-associated molecules.1 CpG and other TLR-ligands show effective immunotherapeutic capacities in cancer treatment by inducing an antitumorigenic immunity.2 They are able to reduce tumor progression by reduction of intratumoral secretion of the immunoregulating chemokine CCL223 and subsequent recruitment of immunosuppressive regulatory T cells (Treg), which express CCR4 the only so far known receptor for CCL22.4 Our recent work has shown that CCL22 secretion by dendritic cells (DC) in the lymph node, mediates tolerance by inducing DC-Treg contacts.5 Indeed, in the absence of CCL22, immune responses to vaccination were stronger and resulted in tumor rejection.6 Therefore, we are aiming to investigate the effects of TLR-ligands on systemic CCL22 levels, elucidating all involved mechanisms to identify new targets for cancer immunotherapy.Materials and MethodsT, B and CD11c+ DCs of wildtype (wt) and RAG1-/- mice were isolated from splenocytes by magnetic-activated cell sorting for in vitro assays. Different co-cultures were incubated with CpG and GM-CSF, known as an CCL22 inducer.5 For in vivo experiments, wt mice were treated with CpG, R484 or poly(I:C) alone and in combination with GM-CSF. CCL22-levels in a number of organs were analyzed.ResultsAnalyzing the different immune cell compartments in vitro, we found that DCs in whole splenocytes secrete CCL22 during culture while DC cultured alone showed no CCL22 secretion. When treated with CpG, CCL22-levels were reduced in splenocytes, while it was induced in DC culture alone. The same results were seen when RAG splenocytes, that lack functional B and T cells, were cultured with CpG. CpG treated B cells were able to suppress CCL22 secretion by DC unlike T cells alone. Co-cultures of T and B cells treated with CpG, however, induced the strongest CCL22 suppression in DC. In vivo, we could show that all TLR ligands tested reduced CCL22 in a number of organs significantly. Furthermore, CpG showed the strongest suppression of CCL22 even in the presence of the CCL22 inducer GM-CSF.5ConclusionsWe could show that B cells with T cells mediate CCL22 suppression by TLR ligands. The fact that CpG was able to reduce CCL22 levels even in the presence of the inducer GM-CSF demonstrates the potent CCL22 suppressive capacity of TLR ligands.ReferencesO’Neill LA, et al. The history of toll-like receptors – redefining innate immunity. Nat Rev Immunol 2013;13(6):453–60.Rothenfusser S, et al. Recent advances in immunostimulatory CpG oligonucleotides. Curr Opin Mol Ther 2003;5(2):98–106.Wang S, et al. Intratumoral injection of a CpG oligonucleotide reverts resistance to PD-1 blockade by expanding multifunctional CD8+ T cells. Proc Natl Acad Sci U S A 2016;113(46): E7240–E7249.Rapp M, et al. CCL22 controls immunity by promoting regulatory T cell communication with dendritic cells in lymph nodes. J Exp Med 2019;216(5):1170–1181.Piseddu I, et al. Constitutive expression of CCL22 is mediated by T cell-derived GM-CSF. J Immunol 2020;205(8):2056–2065.Anz D, et al. Suppression of intratumoral CCL22 by type i interferon inhibits migration of regulatory T cells and blocks cancer progression. Cancer Res 2015;75(21):4483–93.Disclosure InformationJ. Grün: None. I. Piseddu: None. C. Perleberg: None. N. Röhrle: None. S. Endres: None. D. Anz: None.

scholarly journals Toll-Like Receptor 4 Signaling Leads to Severe Fungal Infection Associated with Enhanced Proinflammatory Immunity and Impaired Expansion of Regulatory T Cells

2009 ◽  
Vol 78 (3) ◽  
pp. 1078-1088 ◽  
Author(s):  
Flávio V. Loures ◽  
Adriana Pina ◽  
Maíra Felonato ◽  
Eliseu F. Araújo ◽  
Katia R. M. Leite ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
T Cells ◽  
Regulatory T Cells ◽  
Treg Cells ◽  
Interleukin 12 ◽  
Necrosis Factor Alpha ◽  
Tlr4 Signaling ◽  
Inflammatory Reactions ◽  
Cell Immunity

ABSTRACT Toll-like receptors (TLRs) present in innate immune cells recognize pathogen molecular patterns and influence immunity to control the host-parasite interaction. The objective of this study was to characterize the involvement of TLR4 in the innate and adaptive immunity to Para co c cidioides brasiliensis, the most important primary fungal pathogen of Latin America. We compared the responses of C3H/HeJ mice, which are naturally defective in TLR4 signaling, with those of C3H/HePas mice, which express functional receptors, after in vitro and in vivo infection with P. brasiliensis. Unexpectedly, we verified that TLR4-defective macrophages infected in vitro with P. brasiliensis presented decreased fungal loads associated with impaired synthesis of nitric oxide, interleukin-12 (IL-12), and macrophage chemotactic protein 1 (MCP-1). After intratracheal infection with 1 million yeasts, TLR4-defective mice developed reduced fungal burdens and decreased levels of pulmonary nitric oxide, proinflammatory cytokines, and antibodies. TLR4-competent mice produced elevated levels of IL-12 and tumor necrosis factor alpha (TNF-α), besides cytokines of the Th17 pattern, indicating a proinflammatory role for TLR4 signaling. The more severe infection of TLR4-normal mice resulted in increased influx of activated macrophages and T cells to the lungs and progressive control of fungal burdens but impaired expansion of regulatory T cells (Treg cells). In contrast, TLR4-defective mice were not able to clear their diminished fungal burdens totally, a defect associated with deficient activation of T-cell immunity and enhanced development of Treg cells. These divergent patterns of immunity, however, resulted in equivalent mortality rates, indicating that control of elevated fungal growth mediated by vigorous inflammatory reactions is as deleterious to the hosts as low fungal loads inefficiently controlled by limited inflammatory reactions.

Efficient Treatment of Murine Acute Graft-Versus-Host Disease with In Vitro Expanded CD4+CD25+ Regulatory T Cells

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2987-2987
Author(s):  
Tina J Boeld ◽  
Kristina Doser ◽  
Corinna Lang-Schwarz ◽  
Elisabeth Huber ◽  
Reinhard Andreesen ◽  
...  
Keyword(s):  
T Cells ◽  
B Cells ◽  
Regulatory T Cells ◽  
Graft Versus Host Disease ◽  
Acute Gvhd ◽  
Treg Cells ◽  
Host Disease ◽  
Graft Versus Host ◽  
Acute Graft

Abstract Abstract 2987 Acute graft-versus-host disease (GVHD) is a frequent complication after allogeneic bone marrow transplantation (BMT). We previously showed that the adoptive transfer of donor-type CD4+CD25+ regulatory T cells (Treg) at the time of BMT prevents acute GVHD in murine models. However, the therapeutic potential of donor-derived Treg cells for the treatment of established acute GVHD has not yet been examined in detail. In analogy to potential clinical applications we now tested the capacity of in vitro expanded Treg cells to ameliorate acute GVHD after haploidentical BMT (BALB/c→CB6F1). CD4+CD25highCD62L+ Treg cells were purified by FACS and stimulated polyclonally using anti-CD3/CD28-coated beads. Cells expanded on average 130±19-fold (n=7) within 2 wks and maintained high levels of FoxP3 expression (96, 8±0, 8% FoxP3+ cells; n=7) as well as potent immunosuppressive activity in vitro. For the induction of acute GVHD CB6F1 recipients were lethally irradiated and transplanted with 2.5×106 BM cells in combination with 5×106 splenocytes. All animals developed severe GVHD by d11, as revealed by an increase of the GVHD severity score (2.3±0.4 in GVHD animals vs 0±0 in BM controls, p<0.001, n=1–11) and by histological analyses of the gut (score: 7.8±0.4 for the GVHD group vs 0.2±0.2 for BM controls, p =0.046, n=3). When animals with acute GVHD were treated with 5×106 expanded CD4+CD25highCD62L+ Treg cells on d11 after BMT, they initially developed progressive GVHD comparable to non-treated GVHD animals, as indicated by weight loss and an increase of the GVHD score. However from d44 post BMT onwards, Treg-treated GVHD animals regained body weight (d44: 75±3% vs 67±2% of initial weight; p <0.05; n=9–10) and their clinical GVHD score (d44: 6±0 vs 4.3±0.4; p <0.05; n=9–10) decreased. While all non-treated GVHD animals succumbed to disease by d67 after transplantation, 50% of Treg-treated GVHD animals survived for at least 100d (p =0, 002; n=16–21). As immune reconstitution and in particular reconstitution of the lymphocyte compartment is impaired in animals with GVHD, we analyzed the effect of Treg therapy on the reconstitution of the lymphoid and myeloid compartment. At d21 after BMT spleen and BM of non-treated as well as Treg-treated GVHD animals were completely lymphopenic as compared to control mice and both organs contained exceptionally high numbers of granulocytes. Unlike non-treated GVHD animals, however, Treg-treated recipients by d60 showed a recovery of the lymphocyte compartment in spleen (10±2.6×106 T cells and 23.5±12.5×106 B cells in Treg-treated vs 3.0±0.6×106 T cells and 1.5±0.4×106 B cells in non-treated GVHD animals vs 26.25±2.6×106 T cells and 63.9±9.1×106 B cells in BM controls) and BM (0.7±0.1×106 T cells and 8.6±4×106 B cells in Treg-treated vs 0.3±0.01×106 T cells and 0.7±0.4 ×106 B cells in non-treated GVHD animals vs 0.4±0.03×106 T cells and 11.2±0.6×106 B cells in BM controls), while the number of granulocytes decreased constantly. Successful treatment with Treg cells was finally accompanied by a reconstitution of the lymphatic system comparable to control mice. Furthermore, successfully treated mice showed only mild histological signs of gut GVHD at d100 that was significantly lower then those in non-treated GVHD animals with end-stage disease (score: 4.2±1 vs 9.9±1.5 in treated vs non-treated animals, p =0.006, n=4–6). Taken together, these results indicate that in vitro expanded natural Treg cells may not only be effective for the prevention, but also for the treatment of acute GVHD after allogeneic BMT. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Characterization of immunoactive and immunotolerant CD4+ T cells in breast cancer by measuring activity of signaling pathways that determine immune cell function

2020 ◽  
Author(s):  
Yvonne Wesseling-Rozendaal ◽  
Arie van Doorn ◽  
Karen Willard-Gallo ◽  
Anja van de Stolpe
Keyword(s):  
Breast Cancer ◽  
Signal Transduction ◽  
Immune Response ◽  
T Cells ◽  
Cd4 T Cells ◽  
Treg Cells ◽  
Cd4 T Cell ◽  
Cancer Tissue ◽  
Pathway Activity

AbstractCancer immunotolerance can be reversed by checkpoint blockade immunotherapy in some patients, but response prediction remains a challenge. CD4+ T cells play an important role in activating adaptive immune responses against cancer. Conversion to an immune suppressive state impairs the anti-cancer immune response and is mainly effected by CD4+ Treg cells. A number of signal transduction pathways activate and control functions of CD4+ T cell subsets. As previously described, assays have been developed which enable quantitative measurement of the activity of signal transduction pathways (e.g. TGFβ, NFκB, PI3K-FOXO, JAK-STAT1/2, JAK-STAT3, Notch) in a cell or tissue sample. Using these assays, pathway activity profiles for various CD4+ T cell subsets were defined and cellular mechanisms underlying breast cancer-induced immunotolerance investigated in vitro. Results were used to measure the immune response state in a clinical breast cancer study.MethodsSignal transduction pathway activity scores were measured on Affymetrix expression microarray data of resting, immune-activated, and immune-activated CD4+ T cells incubated with breast cancer tissue supernatants, and of CD4+ Th1, Th2, and Treg cells, and in a clinical study in which CD4+ T cells were derived from blood, lymph node and cancer tissue from primary breast cancer patients (n=10).ResultsIn vitro CD4+ T cell activation induced PI3K, NFκB, JAK-STAT1/2, and JAK-STAT3 pathway activity. Simultaneous incubation with primary cancer supernatant reduced PI3K and NFκB, and partly reduced JAK-STAT3, pathway activity, while simultaneously increasing TGFβ pathway activity; characteristic of an immune tolerant state. CD4+ Th1, Th2, and Treg cells all had a specific pathway activity profile, with activated immune suppressive Treg cells characterized by NFκB, JAK-STAT3, TGFβ, and Notch pathway activity. An immune tolerant pathway profile was identified in CD4+ T cells from tumor infiltrate of a subset of primary breast cancer patients which could be contributed to activated Treg cells. A Treg pathway profile was also identified in blood samples.ConclusionSignaling pathway assays can be used to quantitatively measure the functional immune response state of lymphocyte subsets in vitro and in vivo. Clinical results suggest that in primary breast cancer the adaptive immune response of CD4+ T cells has frequently been replaced by immunosuppressive Treg cells, potentially causing resistance to checkpoint inhibition. In vitro study results suggest that this effect is mediated by soluble factors from cancer tissue (e.g. TGFβ). Signaling pathway activity analysis on TIL and/or blood samples is expected to improve predicting and monitoring response to checkpoint inhibitor immunotherapy.

scholarly journals The relationship between human thymus-derived regulatory T cells, TGF-β-induced regulatory T cells and conventional CD4+ T cells as revealed by proteomics

2021 ◽  
Author(s):  
Mark Mensink ◽  
Ellen Schrama ◽  
Maartje van den Biggelaar ◽  
Derk Amsen ◽  
Jannie Borst ◽  
...  
Keyword(s):  
T Cells ◽  
Regulatory T Cells ◽  
Protein Expression ◽  
Treg Cell ◽  
Ex Vivo ◽  
Foxp3 Expression ◽  
Treg Cells ◽  
Cell Populations ◽  
The Relationship

The CD4+ regulatory T (Treg) cell lineage, as defined by FOXP3 expression, comprises thymus-derived (t)Treg cells and peripherally induced (p)Treg cells. In human, naive tTreg cells can be purified from blood, but occur in low abundance, while effector pTreg and tTreg cell populations cannot be purified for lack of discriminating cell surface markers. Therefore, studies often employ TGF-β-induced (i)Treg cells that are generated from CD4+ conventional T (Tconv) cells in vitro. Here, we describe the relationship of iTreg cells to tTreg and Tconv cells, as optimally purified from human blood. Global proteomic analysis revealed that iTreg, tTreg and Tconv cell populations each have a unique protein expression pattern. We next used as a benchmark a previously defined proteomic signature that discerns ex vivo naive and effector phenotype Treg cells from Tconv cells and reflects unique Treg cell properties. This Treg cell core signature was largely absent from iTreg cells, while clearly present in simultaneously analyzed tTreg cells. In addition, we used a proteomic signature that distinguishes ex vivo effector Treg cells from Tconv cells and naive Treg cells. This effector Treg cell signature was partially present in iTreg cells. Thus, iTreg cells are distinct from tTreg cells and largely lack the common Treg cell proteomic signature. However, they do have certain protein expression features in common with ex vivo effector Treg cells. These data demonstrate the utility of the core and effector Treg cell signatures as tools to define Treg cell populations and encourage the use of ex vivo Treg cells for functional analyses.

scholarly journals MicroRNA-21 Regulates Diametrically Opposed Biological Functions of Regulatory T Cells

2021 ◽  
Vol 12 ◽  
Author(s):  
Jijun Sun ◽  
Ruiling Liu ◽  
Xiaozhen He ◽  
Jiang Bian ◽  
Wenbo Zhao ◽  
...  
Keyword(s):  
T Cells ◽  
Autoimmune Disease ◽  
Regulatory T Cells ◽  
Cell Activation ◽  
Treg Cells ◽  
Mechanistic Study ◽  
Dendritic Cell Activation ◽  
Adenoviral Delivery

Regulatory T cells (Tregs) are considered important for controlling the onset and development of autoimmune disease. Although studies have shown that miR-21 is expressed at higher levels in Treg cells, it remains largely elusive whether miR-21 regulates the immune-suppressive function of Tregs. In the current study, we generated mice lacking miR-21 specifically in their Tregs and investigated the role of miR-21 in regulating Treg function both in vitro and in vivo. Our study revealed that Tregs lacking miR-21 exhibit normal phenotype and unaltered function in suppressing T cell proliferation and dendritic cell activation in vitro. However, compared with miR-21-sufficient Tregs, they produce significant more IL-17 and IL-10 when under pathogenic Th17-priming condition. Adenoviral delivery of miR-21 into Treg cells is able to reduce the expression of both IL-17 and IL-10. Mechanistic study revealed that miR-21 down-regulates IL-10 expression through direct targeting of IL-10, and suppresses reprogramming of Tregs into IL-17-secreting cells through down-regulating Stat3 activity. However, we detected no significant or marginal difference in the development of various autoimmune diseases between wild type mice and mice with Treg-specific deletion of miR-21. In conclusion, our study demonstrated that miR-21 in Tregs regulates diametrically opposed biological Treg functions and is largely dispensable for the development of autoimmune disease.

Role of regulatory T-cells in autoimmunity

2009 ◽  
Vol 116 (8) ◽  
pp. 639-649 ◽  
Author(s):  
Richard J. Mellanby ◽  
David C. Thomas ◽  
Jonathan Lamb
Keyword(s):  
T Cells ◽  
T Cell ◽  
Regulatory T Cells ◽  
Treg Cell ◽  
Cell Function ◽  
Cell Subset ◽  
Treg Cells ◽  
Self Tolerance

There has been considerable historical interest in the concept of a specialist T-cell subset which suppresses over-zealous or inappropriate T-cell responses. However, it was not until the discovery that CD4+CD25+ T-cells had suppressive capabilities both in vitro and in vivo that this concept regained credibility and developed into one of the most active research areas in immunology today. The notion that in healthy individuals there is a subset of Treg-cells (regulatory T-cells) involved in ‘policing’ the immune system has led to the intensive exploration of the role of this subset in disease resulting in a number of studies concluding that a quantitative or qualitative decline in Treg-cells is an important part of the breakdown in self-tolerance leading to the development of autoimmune diseases. Although Treg-cells have subsequently been widely postulated to represent a potential immunotherapy option for patients with autoimmune disease, several studies of autoimmune disorders have demonstrated high numbers of Treg-cells in inflamed tissue. The present review highlights the need to consider a range of other factors which may be impairing Treg-cell function when considering the mechanisms involved in the breakdown of self-tolerance rather than focussing on intrinsic Treg-cell factors.

scholarly journals Regulatory T cells are less sensitive to glucocorticoid hormone induced apoptosis than CD4+ T cells

APOPTOSIS ◽  
2020 ◽  
Vol 25 (9-10) ◽  
pp. 715-729 ◽  
Author(s):  
Lilla Prenek ◽  
Tímea Litvai ◽  
Noémi Balázs ◽  
Réka Kugyelka ◽  
Ferenc Boldizsár ◽  
...  
Keyword(s):  
T Cells ◽  
Regulatory T Cells ◽  
Treg Cells ◽  
High Dose ◽  
Apoptosis Resistance ◽  
Apoptotic Pathway ◽  
Glucocorticoid Hormone ◽  
Induced Apoptosis

Abstract Earlier we have reported that thymic regulatory T cells (Treg) are resistant to in vivo glucocorticoid hormone (GC)-induced apoptosis, while the most GC-sensitive DP thymocytes died through the activation of mitochondrial apoptotic pathway. Here we analyzed the apoptosis-inducing effect of high dose (10–6 M) in vitro dexamethasone (DX) treatment in mouse thymic- and splenic Tregs and CD4+ T cells. Activation of both extrinsic and intrinsic apoptotic pathways started after 2 h of DX treatment in CD4 SP thymocytes and was 3 × higher than in CD4+ splenocytes, while in Treg cells, weak activation of the extrinsic apoptotic pathway started only after 3 h. We also investigated the expression of 21 apoptosis-related molecules using a protein array and found higher level of both pro-and anti-apoptotic molecules in Tregs compared to CD4+ T cells. 4 h in vitro DX treatment induced upregulation of most apoptosis-related molecules both in Tregs and CD4+ T cells, except for the decrease of Bcl-2 expression in CD4+ T cells. We found high basal cytosolic Ca2+ levels in untreated Treg cells, which further increased after DX treatment, while the specific TCR-induced Ca2+ signal was lower in Tregs than in CD4+ T cells. Our results suggest that in the background of the relative apoptosis resistance of Treg cells to GCs might be their high basal cytosolic Ca2+ level and upregulated Bcl-2 expression. In contrast, downregulation of Bcl-2 expression in CD4+ T cells can explain their higher, DX-induced apoptosis sensitivity.

scholarly journals CD70 expression determines the therapeutic efficacy of expanded human regulatory T cells

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Rebeca Arroyo Hornero ◽  
Christos Georgiadis ◽  
Peng Hua ◽  
Dominik Trzupek ◽  
Li-Zhen He ◽  
...  
Keyword(s):  
T Cells ◽  
Regulatory T Cells ◽  
Human Peripheral Blood ◽  
Significant Proportion ◽  
Treg Cells ◽  
Regulatory Function ◽  
Ligand Interaction ◽  
Genetic Deletion

AbstractRegulatory T cells (Tregs) are critical mediators of immune homeostasis. The co-stimulatory molecule CD27 is a marker of highly suppressive Tregs, although the role of the CD27-CD70 receptor-ligand interaction in Tregs is not clear. Here we show that after prolonged in vitro stimulation, a significant proportion of human Tregs gain stable CD70 expression while losing CD27. The expression of CD70 in expanded Tregs is associated with a profound loss of regulatory function and an unusual ability to provide CD70-directed co-stimulation to TCR-activated conventional T cells. Genetic deletion of CD70 or its blockade prevents Tregs from delivering this co-stimulatory signal, thus maintaining their regulatory activity. High resolution targeted single-cell RNA sequencing of human peripheral blood confirms the presence of CD27−CD70+ Treg cells. These findings have important implications for Treg-based clinical studies where cells are expanded over extended periods in order to achieve sufficient treatment doses.

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