scholarly journals Treg Therapies Revisited: Tolerance Beyond Deletion

2021 ◽  
Vol 11 ◽  
Author(s):  
Nina Pilat ◽  
Jonathan Sprent
Keyword(s):  
T Cells ◽  
Immune Tolerance ◽  
Therapeutic Potential ◽  
Tolerance Induction ◽  
Allogeneic Transplantation ◽  
Immunosuppressive Drugs ◽  
Long Term Results ◽  
Inflammatory Reactions

Induction of immune tolerance is the Holy Grail in transplantation medicine and autoimmunity. Currently, patients are required to use immunosuppressive drugs for the rest of their lives, resulting in unwanted side effects and complication from global suppression of the immune response. It is well established that regulatory T cells (Tregs) are critical for the maintenance of immune tolerance towards self-antigens by several mechanisms of immune regulation, in parallel with intrathymic deletion of self-reactive T cells during ontogeny. Therefore, approaches for increasing Treg numbers or function in vivo could provide an all-purpose solution for tolerance induction. Currently, most state-of-the-art therapeutics for treating autoimmune diseases or preventing allograft rejection work either by general immunosuppression or blocking inflammatory reactions and are non-specific. Hence, these approaches cannot provide satisfactory long-term results, let alone a cure. However, in animal models the therapeutic potential of Treg expansion for inducing effective tolerance has now been demonstrated in various models of autoimmunity and allogeneic transplantation. Here, we focus on therapies for increasing the size of the Treg pool by expanding endogenous Treg numbers in vivo or by adoptive transfer of Tregs. In particular, we discuss IL-2 based approaches (low dose IL-2, IL-2 complexes) for inducing Treg expansion in vivo as well as cell-based approaches (polyclonal, antigen specific, or cell engineered) for adoptive Treg therapy. We also mention new questions arising from the first clinical studies on Treg therapy in the fields of transplantation and autoimmunity.

scholarly journals The Crosstalk between Myeloid Derived Suppressor Cells and Immune Cells: To Establish Immune Tolerance in Transplantation

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Chao Zhang ◽  
Shuo Wang ◽  
Cheng Yang ◽  
Ruiming Rong
Keyword(s):  
T Cells ◽  
Natural Killer ◽  
Immune Cells ◽  
Tolerance Induction ◽  
Suppressor Cells ◽  
Immunosuppressive Drugs ◽  
Myeloid Derived Suppressor Cells ◽  
Immune Tolerant ◽  
Killer T Cells

Myeloid derived suppressor cells (MDSCs) are a heterogeneous population of myeloid precursor and progenitor cells and endowed with a robust immunosuppressive activity in multiple pathophysiological conditions. Recent studies have uncovered the crosstalk between MDSCs and immune cells (i.e., natural killer cells, dendritic cells, macrophages, natural killer T cells, and regulatory T cells) and its role in the establishment and maintenance of immune tolerant microenvironment in transplantation. Considering their strong immunosuppressive capability, MDSCs could become a prospective clinical regimen during transplantation tolerance induction, resulting in long-term graft survival with decreased or without immunosuppressive drugs. The review summarized recent research advances in this field and looked ahead at the research directions in the future.

102 Cord-blood derived NK cells, and CAR-T cells, an attractive improved immunotherapy treatment to be considered for hematological malignancies

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A113-A113
Author(s):  
Mireia Bachiller García ◽  
Lorena Pérez-Amill ◽  
Anthony Battram ◽  
Alvaro Urbano-Ispizua ◽  
Beatriz Martín-Antonio
Keyword(s):  
T Cells ◽  
Tumor Cell ◽  
Cord Blood ◽  
Immune Cells ◽  
In Vivo Models ◽  
Cell Clusters ◽  
Cytotoxicity Assays ◽  
Anti Tumor Activity

BackgroundMultiple myeloma (MM) remains an incurable hematological malignancy where a proportion of patients relapse or become refractory to current treatments. Administration of autologous T cells modified with a chimeric antigen receptor (CAR) against B cell maturation antigen (BCMA) has achieved high percentages of complete responses. Unfortunately, the lack of persistence of CART-BCMA cells in the patient leads to relapses. On the other side, cord-blood derived natural killer cells (CB-NK) is an off-the-shelf cellular immunotherapy option to treat cancer patients with high potential due to their anti-tumor activity. However, clinical results in patients up to date have been sub-optimal. Whereas CB-NK are innate immune cells and their anti-tumor activity is developed in a few hours, CART cells are adaptive immune cells and their activity develops at later time points. Moreover, we previously described that CB-NK secrete inflammatory proteins that promote the early formation of tumor-immune cell clusters bringing cells into close contact and thus, facilitating the anti-tumor activity of T cells. Therefore, we hypothesized that the addition of a small number of CB-NK to CART cells would improve the anti-tumor activity and increase the persistence of CART cells.MethodsT cells transduced with a humanized CAR against BCMA and CB-NK were employed at 1:0.5 (CART:CB-NK) ratio. Cytotoxicity assays, activation markers and immune-tumor cell cluster formation were evaluated by flow cytometry and fluorescence microscopy. In vivo models were performed in NSG mice.ResultsThe addition of CB-NK to CART cells demonstrated higher anti-MM efficacy at low E:T ratios during the first 24h and in long-term cytotoxicity assays, where the addition of CB-NK to CART cells achieved complete removal of tumor cells. Analysis of activation marker CD69 and CD107a degranulation from 4h to 24h of co-culturing proved differences only at 4h, where CD69 and CD107a in CART cells were increased when CB-NK were present. Moreover, CB-NK accelerated an increased formation of CART-tumor cell clusters facilitating the removal of MM cells. Of note, CB-NK addition did not increase total TNFα and IFNγ production. Finally, an in vivo model of advanced MM with consecutive challenge to MM cells evidenced that the addition of CB-NK achieved the highest efficacy of the treatment.ConclusionsOur results suggest that the addition of ‘off-the-shelf’ CB-NK to CART cells leads to a faster and earlier immune response of CART cells with higher long-term maintenance of the anti-tumor response, suggesting this combinatorial therapy as an attractive immunotherapy option for MM patients.

scholarly journals CD28 Costimulation Is Required for In Vivo Induction of Peripheral Tolerance in CD8 T Cells

2002 ◽  
Vol 197 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Melanie S. Vacchio ◽  
Richard J. Hodes
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Tolerance Induction ◽  
Peripheral Tolerance ◽  
Cd8 Cells ◽  
Costimulatory Signal ◽  
Cd28 Costimulation

Whereas ligation of CD28 is known to provide a critical costimulatory signal for activation of CD4 T cells, the requirement for CD28 as a costimulatory signal during activation of CD8 cells is less well defined. Even less is known about the involvement of CD28 signals during peripheral tolerance induction in CD8 T cells. In this study, comparison of T cell responses from CD28-deficient and CD28 wild-type H-Y–specific T cell receptor transgenic mice reveals that CD8 cells can proliferate, secrete cytokines, and generate cytotoxic T lymphocytes efficiently in the absence of CD28 costimulation in vitro. Surprisingly, using pregnancy as a model to study the H-Y–specific response of maternal T cells in the presence or absence of CD28 costimulation in vivo, it was found that peripheral tolerance does not occur in CD28KO pregnants in contrast to the partial clonal deletion and hyporesponsiveness of remaining T cells observed in CD28WT pregnants. These data demonstrate for the first time that CD28 is critical for tolerance induction of CD8 T cells, contrasting markedly with CD28 independence of in vitro activation, and suggest that the role of CD28/B7 interactions in peripheral tolerance of CD8 T cells may differ significantly from that of CD4 T cells.

scholarly journals Development of Stable Chimeric IL-15 for Trans-Presentation by the Antigen Presenting Cells

2021 ◽  
Vol 12 ◽  
Author(s):  
Manoj Patidar ◽  
Naveen Yadav ◽  
Sarat K. Dalai
Keyword(s):  
T Cells ◽  
T Cell ◽  
Half Life ◽  
Therapeutic Potential ◽  
Chimeric Protein ◽  
Antigen Presenting Cells ◽  
T Cell Response ◽  
Antigen Presenting

IL-15 is one of the important biologics considered for vaccine adjuvant and treatment of cancer. However, a short half-life and poor bioavailability limit its therapeutic potential. Herein, we have structured IL-15 into a chimeric protein to improve its half-life enabling greater bioavailability for longer periods. We have covalently linked IL-15 with IgG2 base to make the IL-15 a stable chimeric protein, which also increased its serum half-life by 40 fold. The dimeric structure of this kind of IgG based biologics has greater stability, resistance to proteolytic cleavage, and less frequent dosing schedule with minimum dosage for achieving the desired response compared to that of their monomeric forms. The structured chimeric IL-15 naturally forms a dimer, and retains its affinity for binding to its receptor, IL-15Rβ. Moreover, with the focused action of the structured chimeric IL-15, antigen-presenting cells (APC) would transpresent chimeric IL-15 along with antigen to the T cell, that will help the generation of quantitatively and qualitatively better antigen-specific memory T cells. In vitro and in vivo studies demonstrate the biological activity of chimeric IL-15 with respect to its ability to induce IL-15 signaling and modulating CD8+ T cell response in favor of memory generation. Thus, a longer half-life, dimeric nature, and anticipated focused transpresentation by APCs to the T cells will make chimeric IL-15 a super-agonist for memory CD8+ T cell responses.

scholarly journals Lack of Sprouty 1 and 2 enhances survival of effector CD8+ T cells and yields more protective memory cells

2018 ◽  
Vol 115 (38) ◽  
pp. E8939-E8947 ◽  
Author(s):  
Hesham M. Shehata ◽  
Shahzada Khan ◽  
Elise Chen ◽  
Patrick E. Fields ◽  
Richard A. Flavell ◽  
...  
Keyword(s):  
T Cells ◽  
Memory T Cells ◽  
Therapeutic Potential ◽  
Autoimmune Diabetes ◽  
Memory Cells ◽  
Double Knockout ◽  
And Function ◽  
I Cells ◽  
Better Than

Identifying novel pathways that promote robust function and longevity of cytotoxic T cells has promising potential for immunotherapeutic strategies to combat cancer and chronic infections. We show that sprouty 1 and 2 (Spry1/2) molecules regulate the survival and function of memory CD8+ T cells. Spry1/2 double-knockout (DKO) ovalbumin (OVA)-specific CD8+ T cells (OT-I cells) mounted more vigorous autoimmune diabetes than WT OT-I cells when transferred to mice expressing OVA in their pancreatic β-islets. To determine the consequence of Spry1/2 deletion on effector and memory CD8+ T cell development and function, we used systemic infection with lymphocytic choriomeningitis virus (LCMV) Armstrong. Spry1/2 DKO LCMV gp33-specific P14 CD8+ T cells survive contraction better than WT cells and generate significantly more polyfunctional memory T cells. The larger number of Spry1/2 DKO memory T cells displayed enhanced infiltration into infected tissue, demonstrating that absence of Spry1/2 can result in increased recall capacity. Upon adoptive transfer into naive hosts, Spry1/2 DKO memory T cells controlled Listeria monocytogenes infection better than WT cells. The enhanced formation of more functional Spry1/2 DKO memory T cells was associated with significantly reduced mTORC1 activity and glucose uptake. Reduced p-AKT, p-FoxO1/3a, and T-bet expression was also consistent with enhanced survival and memory accrual. Collectively, loss of Spry1/2 enhances the survival of effector CD8+ T cells and results in the formation of more protective memory cells. Deleting Spry1/2 in antigen-specific CD8+ T cells may have therapeutic potential for enhancing the survival and functionality of effector and memory CD8+ T cells in vivo.

Treatment of Cerebral Aneurysms With Flow Divertors: Long Term Results in an In Vivo Model

2007 ◽  
Author(s):  
Chander Sadasivan ◽  
Baruch B. Lieber ◽  
Liliana Cesar ◽  
Jaehoon Seong ◽  
Ajay K. Wakhloo
Keyword(s):  
Thrombus Formation ◽  
Cerebral Aneurysms ◽  
Long Term Results ◽  
In Vivo Model ◽  
Parent Artery ◽  
Momentum Exchange ◽  
Aneurysm Neck ◽  
Flow Stasis

Subarachnoid hemorrhagic stroke is a devastating illness with a 30-day mortality rate of 45% and is mostly caused due to the rupture of an intracranial aneurysm. Although these aneurysms are currently treated surgically by clipping, or, endovascularly by coiling and stent-assisted coiling, the feasibility of successfully treating aneurysms solely by the placement of an intravascular flow-diverting mesh across the aneurysm neck was established more than a decade ago [1]. Flow divertors disrupt the momentum exchange between the parent artery and aneurysm and significantly reduce intraaneurysmal hydrodynamic vorticity. The resultant flow stasis promotes thrombus formation within the aneurysm sac, which eventually matures into fibrotic tissue, leading to the exclusion of the aneurysm from the circulation. With the increased use of stents in the intracranial circulation, cases where coiling is not feasible, or is staged as a secondary procedure, are providing clinical evidence of the successful treatment of aneurysms with stents alone [2,3]. Such reports are sporadic and, moreover, the devices used are not designed to be flow divertors. Methodological evidence of the performance of appropriately designed flow divertors in treating cerebral aneurysms is currently unavailable.

The long-term course of factor VIII inhibitors in patients with congenital haemophilia A without immune tolerance induction

2011 ◽  
Vol 105 (01) ◽  
pp. 59-65 ◽  
Author(s):  
Camila Caram ◽  
Roberta Grazielle de Souza ◽  
Júlio Carepa de Sousa ◽  
Tatiana Araújo Pereira ◽  
Ana Maria do Amaral Cerqueira ◽  
...  
Keyword(s):  
Confidence Interval ◽  
Factor Viii ◽  
Immune Tolerance ◽  
Tolerance Induction ◽  
Clotting Factor ◽  
Haemophilia A ◽  
Immune Tolerance Induction ◽  
Inhibitor Titre ◽  
Very High

SummaryThe development of alloantibodies that inhibit or neutralise the function of factor VIII is considered the most serious complication of the treatment of congenital haemophilia A. In order to describe their course without immune tolerance induction (ITI), we documented data on all performed inhibitor tests with dates as well as on clotting factor infusions of all consecutive patients who were treated in our centre between 1993 and 2006. Patients were tested every 7.1 months (95% confidence interval [CI], 6.6–7.8). A ‘sustained negative inhibitor status’ was defined as consistent non-positive inhibitor measurements for two years or longer. A total of 60/486 (12%) patients tested had a positive inhibitor titre in two or more occasions. Most of the patients (56%) with a maximum inhibitor titre of < 5 Bethesda unit (BU)/ml (named “low titre inhibitor”) developed a sustained negative inhibitor status. Among patients with high (5–9.9 BU/ml) and very high (≥ 10 BU/ ml) inhibitor titres, the proportions were 50% and 3%, respectively. Our findings suggest that ITI might not be needed for all patients with non-transient inhibitors, especially when their maximum inhibitor titre is below 10 BU/ml. Further studies in countries where ITI is not available are needed to examine predictors of the natural sustained negative inhibitor status.

scholarly journals Effect of Low-Immunogenic Yogurt Drinks and Probiotic Bacteria on Immunoreactivity of Cow’s Milk Proteins and Tolerance Induction—In Vitro and In Vivo Studies

Nutrients ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3390
Author(s):  
Barbara Wróblewska ◽  
Anna Kaliszewska-Suchodoła ◽  
Ewa Fuc ◽  
Lidia Hanna Markiewicz ◽  
Anna Maria Ogrodowczyk ◽  
...  
Keyword(s):  
Therapeutic Potential ◽  
Tolerance Induction ◽  
Milk Proteins ◽  
In Vivo Studies ◽  
Cow’S Milk ◽  
Milk Allergy ◽  
Cow's Milk ◽  
Safe Product

There is no effective therapy for milk allergy. The role of lactic acid bacteria (LAB) and probiotics in protection against allergy-related outcomes is still under investigation. The aim of the study was to evaluate the immunomodulative and therapeutic potential of yogurt drinks in cow’s milk allergy (CMA) management. We compared immunoreactivity of α-casein (α-CN), β-casein (β-CN), κ-casein (κ-CN), α-lactalbumin (α-LA), and β-lactoglobulin (β-LG) in 27 yogurt drinks fermented with different basic yogurt cultures, or yogurt cultures enriched with Lactobacillus plantarum and/or Bifidobacterium lactis strains, by competitive ELISA assay. Drinks with the lowest antigenic potential were used as allergoids for CMA therapy. BALB/c mice were sensitized via intraperitoneal injection of α-CN + β-LG mixture with aluminum adjuvant, and gavaged with increasing doses of selected low-immunogenic drinks (YM—basic, or YM-LB—enriched with L. plantarum and B. lactis) to induce tolerance. Milk- or phosphate-buffered saline (PBS)-dosed mice served as controls. Compared to milk, the immunoreactivity of proteins in drinks increased or decreased, depending on the bacterial sets applied for fermentation. Only a few sets acted synergistically in reducing immunoreactivity. The selected low-immunogenic drinks stimulated allergic mice for profiling Th2 to Th1 response and acquire tolerance, and the effect was greater with YM-LB drink, which during long-lasting interventional feeding strongly increased the secretion of regulatory cytokines, i.e., IL-10 and TGF-β, and IgA and decreased IL-4, IgE, and anti-(α-CN + β-LG) IgG1. The studies revealed variations in the potency of yogurt bacteria to change allergenicity of milk proteins and the need for their strict selection to obtain a safe product for allergy sufferers. The YM-LB drink with reduced antigenic potential may be a source of allergoids used in the immunotherapy of IgE mediated CMA, but further clinical or volunteer studies are required.

scholarly journals In situ recruitment of regulatory T cells promotes donor-specific tolerance in vascularized composite allotransplantation

2020 ◽  
Vol 6 (11) ◽  
pp. eaax8429 ◽  
Author(s):  
James D. Fisher ◽  
Wensheng Zhang ◽  
Stephen C. Balmert ◽  
Ali M. Aral ◽  
Abhinav P. Acharya ◽  
...  
Keyword(s):  
T Cells ◽  
Regulatory T Cells ◽  
Immune Tolerance ◽  
Immunosuppressive Drugs ◽  
Vascularized Composite Allotransplantation ◽  
Local Enrichment ◽  
Donor Specific Tolerance ◽  
Specific Tolerance

Vascularized composite allotransplantation (VCA) encompasses face and limb transplantation, but as with organ transplantation, it requires lifelong regimens of immunosuppressive drugs to prevent rejection. To achieve donor-specific immune tolerance and reduce the need for systemic immunosuppression, we developed a synthetic drug delivery system that mimics a strategy our bodies naturally use to recruit regulatory T cells (Treg) to suppress inflammation. Specifically, a microparticle-based system engineered to release the Treg-recruiting chemokine CCL22 was used in a rodent hindlimb VCA model. These “Recruitment-MP” prolonged hindlimb allograft survival indefinitely (>200 days) and promoted donor-specific tolerance. Recruitment-MP treatment enriched Treg populations in allograft skin and draining lymph nodes and enhanced Treg function without affecting the proliferative capacity of conventional T cells. With implications for clinical translation, synthetic human CCL22 induced preferential migration of human Treg in vitro. Collectively, these results suggest that Recruitment-MP promote donor-specific immune tolerance via local enrichment of suppressive Treg.

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