scholarly journals Recent advances with Treg depleting fusion protein toxins for cancer immunotherapy

Immunotherapy ◽  
2019 ◽  
Vol 11 (13) ◽  
pp. 1117-1128 ◽  
Author(s):  
Pankaj Kumar ◽  
Amit Kumar ◽  
Sadiya Parveen ◽  
John R Murphy ◽  
William Bishai
Keyword(s):  
Diphtheria Toxin ◽  
Antitumor Immunity ◽  
T Regulatory Cells ◽  
Treg Cells ◽  
Clinical Development ◽  
Bacterial Toxins ◽  
Regulatory Cells ◽  
Protein Toxins ◽  
Cancer Immunotherapies ◽  
Pseudomonas Aeruginosa Exotoxin

T regulatory cells (Tregs) are an important T cell population for immune tolerance, prevention of autoimmune diseases and inhibition of antitumor immunity. The tumor-promoting role played by Tregs in cancer has prompted numerous approaches to develop immunotherapeutics targeting Tregs. One approach to depletion of Treg cells is retargeting the highly potent cytotoxic activity of bacterial toxins. These agents capitalize on the well-characterized bacterial toxins, diphtheria toxin and Pseudomonas aeruginosa exotoxin A–both of which harbor membrane translocation domains and enzymatic domains that catalytically halt protein synthesis within intoxicated eukaryotic cells and act at picomolar or subpicomolar concentrations. In this review, we summarize the preclinical and clinical development of several Treg-depleting cancer immunotherapies based on these two bacterial toxins.

Endogenous IL-β Selectively Converts T Regulatory Cells Into IL-17 Producers During Antigen Stimulation

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 586-586
Author(s):  
Lequn Li ◽  
Jin sub Kim ◽  
Vassiliki A Boussiotis
Keyword(s):  
T Cells ◽  
T Regulatory Cells ◽  
Neutralizing Antibody ◽  
Treg Cells ◽  
Conversion Process ◽  
Regulatory Cells ◽  
Antigen Stimulation ◽  
Tnf Α ◽  
Treg Population

Abstract Abstract 586 A major challenge of the immune system is to fight pathogens and tumor antigens while preserving tolerance to self-antigen. T regulatory cells (Treg) are critical extrinsic regulators of immune tolerance and maintenance of lymphoid homeostasis. Recently it was determined that, when used as cell-based immunosuppressive therapy, Treg have a potent effect in preventing GvHD in patients undergoing allogeneic stem cell transplantation. However, several studies suggest that the Treg phenotype is not at end stage of differentiation. Treg can express and produce effector cytokines including IFN-γ and IL-17 under certain conditions, particularly in the context of inflammatory milieu, suggesting that Treg may convert into inflammatory mediators. IL-1β and TNF-α are critical inflammatory cytokines that have been implicated in GvHD. The precise role and the mechanism(s) via which these cytokines may affect development of GvHD remain unclear. In the presence study, we sought to determine whether IL-1β and TNF-α regulate the properties of Treg and specifically whether these cytokines affect Treg expansion and/or conversion into IL-17 producing cells. CD4+CD25+Treg cells were isolated from B6 mice and were stimulated with anti-CD3-plus-anti-CD28 mAbs in the presence of either media, IL-1β or TNF-α. Addition of either cytokine induced Treg proliferation as determined by CFSE. Assessment of intracellular IL-17 expression by flow cytometry and IL-17 production by ELISA revealed that IL-1β but not TNF-α induced conversion of Treg into IL-17 producing cells, suggesting that conversion was mediated via pathways distinct from those that regulate cell cycle progression. To evaluate conversion of Treg to IL-17 producers during antigen stimulation and to determine the role of IL-1β in this process, we used neutral culture conditions in which no exogenous cytokines were supplied. Treg cells isolated from Foxp3GFP-KI mouse were added to cultures of naive conventional CD4+ T cells (Tc) in the presence of APC and anti-CD3 mAb. We found that these conditions preferentially induced conversion of Treg to IL-17 producing cells. To determine the role of IL-1β in this conversion process, we used IL-1β neutralizing antibody. Addition of anti-IL-1β neutralizing antibody reduced IL-17 production to almost undetectable levels. Because it has exogenous IL-6 can induce IL-17 production by both Treg and Tc, we evaluated whether endogenous IL-6 was involved in the conversion of Treg into IL-17 producing cells in our system. Addition of a combination of IL-6 neutralizing and IL-6 receptor blocking antibodies did not affect IL-17 production, suggesting that the conversion process of Treg into IL-17 producing cells was dependent on endogenous IL-1β rather than IL-6. To determine whether IL-1β was mandatory for this process, we used T cells from IL-1R deficient mice. Individual culture of IL−1R−/− Tc or IL-1R−/− Treg with wild type (wt) APC and co-culture of IL-1R−/− Tc and IL-1R−/− Treg with wt APC did not result in detectable IL-17 production. Similarly, no IL-17 production was observed when wt instead of IL-1R−/− Tc were used. In contrast, substitution of IL-1R−/− Treg with wt Treg resulted in abundant IL-17 production. To investigate the in vivo biological relevance of our findings we adoptively transferred Treg cells from either congenic B6.PL mice or IL-1R1−/− mice into IL-1R1−/− recipients, which were then immunized with KLH in IFA. Three days after immunization both IL-1R−/− Treg and IL-1R−/− Tc cells were incapable of producing detectable levels of IL-17 or expressing RORγt, the key transcriptional factor of IL-17. In contrast, a significant percentage of IL-17 and RORγt positive cells were detected within the adoptively transferred Thy1.1+ Treg population. Mechanistic analysis revealed that IL-1β induced activation of p38 and JNK in Treg and addition of pharmacologic inhibitors specific for these MAPKs abrogated IL-17 production. Our studies reveal that although Treg have primarily immunosuppressive functions they may also facilitate pro-inflammatory responses as they can be converted into IL-17 producing cells by IL-1β. These observations may have significant implications on clinical strategies that employ Treg for control of GvHD and suggest that further intervention might be required to prevent attainment of pro-inflammatory properties by Treg while maintaining their suppressive function. Disclosures: No relevant conflicts of interest to declare.

Generation of T Regulatory Cells in Children with Newly Diagnosed Type 1 Diabetes Mellitus

2011 ◽  
Vol 120 (02) ◽  
pp. 101-109 ◽  
Author(s):  
W. Łuczyński ◽  
N. Wawrusiewicz-Kurylonek ◽  
A. Szypowska ◽  
E. Iłendo ◽  
A. Bossowski ◽  
...  
Keyword(s):  
Gene Expression ◽  
Diabetes Mellitus ◽  
T Regulatory Cells ◽  
Mrna Level ◽  
Treg Cells ◽  
Newly Diagnosed ◽  
Regulatory Cells ◽  
Proliferation Assays ◽  
And Control

AbstractThere is increasing evidence that T-regulatory (Treg) cells could be used to prevent or cure autoimmune diseases including type 1 diabetes mellitus (T1DM). The aim of the present study was to verify the hypothesis that functional Treg cells can be generated from conventional T-cells separated from a small amount of peripheral blood of children with newly diagnosed T1DM (N=25).CD4+CD25- cells were cultured with Treg expander (CD3/CD28) and IL-2 for generating de novo Treg cells. The assessment of the expression of selected genes and proteins critical to Treg function and the proliferation assays were performed with the use of real-time RT-PCR and flow cytometry.After a 4-week stimulation with Treg expander and IL-2, the percentage of T-regulatory cells was significantly higher compared to the cells treated with medium alone (with no difference between diabetic and control children). However, we found some disturbances in the gene expression at mRNA level for molecules crucial for T-reg function. The induced Tregs from diabetic and control children were fully functional as assessed in proliferation assays.despite some disturbances at mRNA level in the critical gene expression, the suppressive properties of induced Treg cells from diabetic and control children were effective.

scholarly journals A Biological Circuit Involving Mef2c, Mef2d, and Hdac9 Controls the Immunosuppressive Functions of CD4+Foxp3+ T-Regulatory Cells

2021 ◽  
Vol 12 ◽  
Author(s):  
Eros Di Giorgio ◽  
Liqing Wang ◽  
Yan Xiong ◽  
Lanette M. Christensen ◽  
Tatiana Akimova ◽  
...  
Keyword(s):  
Antitumor Immunity ◽  
T Regulatory Cells ◽  
Transcriptional Repressor ◽  
Regulatory Elements ◽  
Treg Cells ◽  
Loss Of Function ◽  
Anti Cancer ◽  
Physiological Feedback ◽  
Control Tumor

The Mads/Mef2 (Mef2a/b/c/d) family of transcription factors (TFs) regulates differentiation of muscle cells, neurons and hematopoietic cells. By functioning in physiological feedback loops, Mef2 TFs promote the transcription of their repressor, Hdac9, thereby providing temporal control of Mef2-driven differentiation. Disruption of this feedback is associated with the development of various pathologic states, including cancer. Beside their direct involvement in oncogenesis, Mef2 TFs indirectly control tumor progression by regulating antitumor immunity. We recently reported that in CD4+CD25+Foxp3+ T-regulatory (Treg) cells, Mef2d is required for the acquisition of an effector Treg (eTreg) phenotype and for the activation of an epigenetic program that suppresses the anti-tumor immune responses of conventional T and B cells. We now report that as with Mef2d, the deletion of Mef2c in Tregs switches off the expression of Il10 and Icos and leads to enhanced antitumor immunity in syngeneic models of lung cancer. Mechanistically, Mef2c does not directly bind the regulatory elements of Icos and Il10, but its loss-of-function in Tregs induces the expression of the transcriptional repressor, Hdac9. As a consequence, Mef2d, the more abundant member of the Mef2 family, is converted by Hdac9 into a transcriptional repressor on these loci. This leads to the impairment of Treg suppressive properties in vivo and to enhanced anti-cancer immunity. These data further highlight the central role played by the Mef2/Hdac9 axis in the regulation of CD4+Foxp3+ Treg function and adds a new level of complexity to the analysis and study of Treg biology.

scholarly journals Diminished expression of ICOS, GITR and CTLA-4 at the mRNA level in T regulatory cells of children with newly diagnosed type 1 diabetes.

2009 ◽  
Vol 56 (2) ◽  
Author(s):  
Włodzimierz Łuczyński ◽  
Natalia Wawrusiewicz-Kurylonek ◽  
Anna Stasiak-Barmuta ◽  
Remigiusz Urban ◽  
Elzbieta Iłendo ◽  
...  
Keyword(s):  
Type 1 Diabetes ◽  
T Regulatory Cells ◽  
Mrna Level ◽  
Flow Cytometric Analysis ◽  
Treg Cells ◽  
Future Research ◽  
Mrna Levels ◽  
Newly Diagnosed ◽  
Regulatory Cells

Diabetes mellitus is one of the most common chronic diseases in children. T regulatory cells (Tregs) modulate response to autoantigens and probably play a role in pathogenesis of type 1 diabetes (T1DM). The aim of the present study was the assessment of T regulatory cells including their percentages and expression of critical genes in these cells in children with newly diagnosed type 1 diabetes. The examined group consisted of 50 children with T1DM. A flow cytometric analysis of T-cell subpopulations was performed using the following markers: anti-CD4, anti-CD25 and anti-CD127 (=IL-7R). Additionally, T regulatory cells were isolated for assessment of mRNA levels for chosen genes with the real-time RT-PCR technique. The percentages of CD4(+)CD25(high)CD127(dim/-) were very low and did not differ between T1DM and control children. We did not observe any statistically significant differences between healthy and diabetic children in mRNA expression for FoxP3, IL-7R (CD127), IL-8RA, IL-10RA, IL-12A, IL-2RA (CD25), IL-21, STAT1, STAT3, SOCS2, SOCS3, TGF-beta1-R1, TGF-beta-R2 and TBX-21 genes. Interestingly the mRNA level for CTLA-4, ICOS1, IL-23, IL-27, SMAD3 and GITR were lower in Treg cells of children with diabetes compared to the control patients. No disturbances in the percentages of T regulatory cells in patients with diabetes but diminished expression of some elements important in Treg function could be the result of an immunologic imbalance accompanying the onset of the diabetes. The results of our study should be used in future research in the field of immunotherapy in pediatric diabetes.

scholarly journals Critical role of Bcl11b in suppressor function of T regulatory cells and prevention of inflammatory bowel disease

2011 ◽  
Vol 208 (10) ◽  
pp. 2069-2081 ◽  
Author(s):  
Jeffrey VanValkenburgh ◽  
Diana I. Albu ◽  
Chandra Bapanpally ◽  
Sarah Casanova ◽  
Danielle Califano ◽  
...  
Keyword(s):  
Gene Expression ◽  
T Cells ◽  
Cd4 T Cells ◽  
T Regulatory Cells ◽  
Critical Role ◽  
Foxp3 Expression ◽  
Treg Cells ◽  
Regulatory Cells ◽  
Genes Encoding ◽  
Inflammatory Bowel

Dysregulated CD4+ T cell responses and alterations in T regulatory cells (Treg cells) play a critical role in autoimmune diseases, including inflammatory bowel disease (IBD). The current study demonstrates that removal of Bcl11b at the double-positive stage of T cell development or only in Treg cells causes IBD because of proinflammatory cytokine-producing CD4+ T cells infiltrating the colon. Provision of WT Treg cells prevented IBD, demonstrating that alterations in Treg cells are responsible for the disease. Furthermore, Bcl11b-deficient Treg cells had reduced suppressor activity with altered gene expression profiles, including reduced expression of the genes encoding Foxp3 and IL-10, and up-regulation of genes encoding proinflammatory cytokines. Additionally, the absence of Bcl11b altered the induction of Foxp3 expression and reduced the generation of induced Treg cells (iTreg cells) after Tgf-β treatment of conventional CD4+ T cells. Bcl11b bound to Foxp3 and IL-10 promoters, as well as to critical conserved noncoding sequences within the Foxp3 and IL-10 loci, and mutating the Bcl11b binding site in the Foxp3 promoter reduced expression of a luciferase reporter gene. These experiments demonstrate that Bcl11b is indispensable for Treg suppressor function and for maintenance of optimal Foxp3 and IL-10 gene expression, as well as for the induction of Foxp3 expression in conventional CD4+ T cells in response to Tgf-β and generation of iTreg cells.

Modulation of Tryptophan Catabolism by Acute Myeloid Leukemia Cells Acts as a General Mechanism of Immune Tolerance Via the Induction of T Regulatory Cells.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 1345-1345
Author(s):  
Antonio Curti ◽  
Valentina Salvestrini ◽  
Michela Aluigi ◽  
Sara Trabanelli ◽  
Emanuela Ottaviani ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
T Cell ◽  
Myeloid Leukemia ◽  
T Regulatory Cells ◽  
Treg Cells ◽  
T Cell Proliferation ◽  
Regulatory Cells ◽  
Tryptophan Catabolism ◽  
Acute Myeloid

Abstract Indoleamine 2,3-dioxygenase (IDO) enzyme, which catalyzes the conversion of tryptophan into kynurenine, has been identified as a novel immunosuppressive agent by inhibiting T-cell proliferation and is involved in tolerance induction to tumors. We have recently shown that IDO protein is constitutively expressed in a significant subset of newly diagnosed acute myeloid leukemia (AML) patients, resulting in tryptophan catabolism along the kynurenine pathway and in the inhibition of allogeneic T-cell proliferation. Moreover, we demonstrated that IDO-expressing AML cells are capable to promote the differentiation of new CD4+CD25+Foxp3+ T regulatory cells (Treg cells). AML cells may be differentiated into leukemic dendritic cells (AML-DCs) which have increased immunogenicity and may be used as vaccine against leukemia. We in vitro generated DCs from 7 AML samples according to standard procedures and tested IDO expression and activity. At baseline, 5/7 AML samples expressed IDO, whereas 2/7 did not. After differentiation into DCs, IDO+ AML samples showed an up-regulation of IDO mRNA and protein, and IDO− AML cells turned positive. IDO-expressing AML-DCs were capable to catabolize tryptophan into kynurenine metabolite and, functionally, they inhibited allogeneic T-cell proliferation through an IDO-dependent mechanism. Similarly to undifferentiated IDO+ AML blasts, IDO-expressing AML-DCs induced a population of CD4+CD25+Foxp3+ Treg cells, which were capable to suppress in vitro allogeneic naïve T-cell proliferation. These data identify IDO-mediated catabolism as a general tolerogenic mechanism in AML cells, including AML-DCs and raise several concerns for the use of AML-DCs as cellular vaccine against leukemia.

Altered activation of AKT is required for the suppressive function of human CD4+CD25+ T regulatory cells

Blood ◽  
2006 ◽  
Vol 109 (5) ◽  
pp. 2014-2022 ◽  
Author(s):  
Natasha K. Crellin ◽  
Rosa V. Garcia ◽  
Megan K. Levings
Keyword(s):  
T Regulatory Cells ◽  
Ex Vivo ◽  
Active Form ◽  
Suppressor Cells ◽  
Cell Receptor ◽  
Treg Cells ◽  
Regulatory Cells ◽  
Suppressive Function ◽  
Major Mechanism ◽  
Foreign Proteins

Abstract Suppression by T regulatory cells (Treg cells) is a major mechanism by which the immune system controls responses to self and nonharmful foreign proteins. Although there are many different types of Treg cells, the best characterized are those that constitutively express cell-surface IL-2Rα (CD25). We investigated whether altered T-cell–receptor (TCR)–mediated signaling in pure populations of ex vivo human CD4+CD25+ Treg cells might underlie their unique phenotype, including hyporesponsiveness to TCR–mediated activation and lack of cytokine production. CD4+CD25+ Treg cells displayed a consistent defect in phosphorylation of AKT at serine 473 and reduced phosphorylation of the AKT substrates FOXO and S6. Restoration of AKT activity via lentiviral-mediated expression of an inducibly active form of the kinase revealed that reduced activity of this pathway was necessary for the suppressive function of CD4+CD25+ Treg cells. These data represent the first demonstration of a causal association between altered signaling and the function of CD4+CD25+ Treg cells. Moreover, we have created the first system allowing inducible abrogation of suppression through manipulation of the suppressor cells. This system will be a powerful tool to further study the mechanism(s) of suppression by CD4+CD25+ Treg cells.

scholarly journals Subsets of T regulatory cells in patients with IgE-mediated allergy

2019 ◽  
pp. 65-71
Author(s):  
G. S. Nikolov ◽  
Y. D. Todorova ◽  
M. H. Nikolova ◽  
R. G. Emilova ◽  
D. M. Hristova ◽  
...  
Keyword(s):  
T Regulatory Cells ◽  
Clinical Manifestations ◽  
Allergic Diseases ◽  
Treg Cells ◽  
Respiratory Allergy ◽  
Relative Importance ◽  
Regulatory Cells ◽  
Absolute Count ◽  
Ige Mediated ◽  
Healthy Persons

Background. It is presently known that several subsets of T-regulatory (Treg) cells, both natural and inducible maintain tolerance to environmental allergens. But the relative importance of distinct phenotypically defined Treg subsets for the clinical manifestations of IgE-mediated allergy has not been elucidated yet.The aim of the study was to investigate the phenotype and number of different Treg subpopulations from patients with IgE-mediated allergy compared with healthy non-allergic individuals.Materials and methods. A group of 20 patients with clinically manifested IgE allergy and a group of 10 healthy no allergic controls were included in the study. Peripheral blood samples were taken after informed consent. Percentage and absolute count (AC) of the following regulatory subsets: naive (CD45RO-FoxP3lo), memory (RO+FoxP3+), effector (Treg eff, RO+FoxP3hi), induced (CD39+CD134+), Thl7/Treg (CD196+FoxP3+CD4Treg); Tr1 (IL-10+FoxP3-), were determined using standard 8-parameter flow cytometry (BD FACSCanto II).Results and discussion. The share and AC of FoxP3+CD4 Treg was significantly decreased in sensitized patients as compared to controls (mean 0,6% vs. 3,3%, p<0.05 and 8,7 vs. 55 cells/μl p<0.001). In addition, a significantly decreased level of Tr1 cells was observed in the patients with allergy, 0,4% vs. 2,1 % in healthy controls (p<0,05) as well for subset of Thl7/Treg (mean 7,7% vs. 28,4% in healthy persons, p<0.01).Conclusion. The significantly decreased number of FoxP3+CD4 Treg as well as periphery induced Tr1 and Thl7/Treg cells in patients with respiratory allergy lead to dysregulation and loss of peripheral immune tolerance, which is the pathophysiological basis for development of widely spread allergic diseases like allergic rhinitis and bronchial asthma.

scholarly journals Alopecia areata patients show deficiency of FOXP3+CD39+ T regulatory cells and clonotypic restriction of Treg TCR?-chain, which highlights the immunopathological aspect of the disease

2018 ◽  
Author(s):  
Annika Birgitta Margareta Åstrand ◽  
Fatma N Hamed ◽  
Marta Bertolini ◽  
Alfredo Rossi ◽  
Afsaneh Maleki-Dizaji ◽  
...  
Keyword(s):  
Hair Loss ◽  
Alopecia Areata ◽  
T Regulatory Cells ◽  
Treg Cells ◽  
Hair Follicles ◽  
Regulatory Cells ◽  
T Helper 1 ◽  
Autoimmune Reaction ◽  
Lesional Skin ◽  
Pcr Products

Alopecia areata (AA) is a hair loss disorder resulting from an autoimmune reaction against hair follicles. T-helper 1 cells are a major contributor to this disorder, but little is known about the role of T-regulatory cells (Tregs) in AA. Here, we analysed the distribution of circulating Treg subsets in twenty AA patients with active hair loss and fifteen healthy subjects by flow cytometry. The Treg suppressor HLA-DR+ subpopulation was significantly reduced in the patients (P<0.001) and there were significantly fewer cells expressing CD39 among the CD4+CD25+Foxp3+ Treg subpopulation in patients (P=0.001). FOXP3 CD39 Treg cells were also reduced in hair follicles; by 75% in non-lesional skin and 90% in lesional skin, when compared to control healthy skin. To further characterise Treg cells in AA; Tregs (CD4+CD25+FOXP3+) were investigated for their TCR? sequence. PCR products analysed by Next Generation Sequencing techniques, showed that all frequent public clonotypes in AA Tregs were also present in controls at relatively similar frequencies, excepting two public clonotypes: CATSRDEGGLDEKLFF (V15 D1 J1-4) and CASRDGTGPSNYGYTF (V2 D1 J1-2), which were exclusively present in controls. This suggests that these Treg clonotypes may have a protective effect and that they may be an exciting subject for future therapeutic applications.

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