scholarly journals Novel Multi-Target Immunosuppressive Approach for Treatment of Severe Aplastic Anemia

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 3611-3611 ◽  
Author(s):  
Kyle Blaine Russell ◽  
Brandon P Theall ◽  
Lisandra Hernandez ◽  
Hannah M Wavering ◽  
Vesna Jurecic ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Regulatory T Cells ◽  
Autoimmune Diseases ◽  
Aplastic Anemia ◽  
Effector T Cells ◽  
Prolonged Treatment ◽  
Effector T Cell ◽  
New Therapy

Abstract Aplastic Anemia (AA) is an immune-mediated form of acquired bone marrow failure (BMF), which is life-threatening in its severe form (SAA). Fundamental pathological features of AA include development and expansion of auto-reactive effector T cells, effector T cell-mediated apoptosis of all hematopoietic cells (including progenitors and hematopoietic stem cells (HSCs)), BM aplasia, pancytopenia, depletion of HSCs, and severe reduction and functional impairment of regulatory T cells (Tregs). Current standard treatments for AA include: (1) immuno-suppressive therapy (IST) with cyclosporine A (CyA) and anti-thymocyte globulin (ATG) which targets all T cells, and (2) allogeneic or matched unrelated donor BM transplant. While IST remains a standard treatment modality, it is not very effective in treating already ongoing and relapsed AA or SAA. There is really no effective therapy for patients with refractory and relapsed AA who are ineligible for BMT. Among different pathophysiological features of AA, IST targets only the effector T cells, and is much more effective in the early than later stages of AA. Moreover, the combination of IST with other immunosuppressive agents (mycophenolate mofetil, sirolimus etc.) or growth factors does not improve the response or survival of AA patients. Since the incidence of AA is on the rise, there is an urgent need for more efficient new therapies that can attenuate the progression and severity of AA in patients with refractory and relapsed AA who are waiting for or are not candidates for BMT. The complex immune and hematological pathophysiology of AA requires new multipurpose treatment approaches. Accumulating evidence shows that β2 integrin CD11b/CD18 (Mac-1) negatively regulates T cell responses and activation, attenuates inflammation, and facilitates the maintenance of tolerance to self-antigens. For example, activated Mac-1 significantly reduces the T cell-activating capacity of dendritic cells (DCs), represses DC cross-priming of cytotoxic T cells, negatively regulates NK cell activation and function, suppresses differentiation of Th17 T cells which are associated with AA and other autoimmune diseases, ameliorates experimental autoimmune hepatitis, and negatively regulates BCR signaling and maintains autoreactive B cell tolerance. For that reason, Mac-1 is an attractive molecular target for new immune-modulating therapies of autoimmune diseases. Using the clinically relevant mouse SAA model we have evaluated the therapeutic efficacy of Leukadherins (LA1-LA3), novel small molecule agonists and activators of Mac-1, as a novel multipurpose immunosuppressive and anti-inflammatory approach to treat AA. The present studies have demonstrated that administration of LA1 safely and significantly (1) suppresses expansion of effector T cells, (2) decreases effector T cell-mediated apoptosis of target BM cells, (2) reduces BM aplasia, (3) minimalizes the loss of HSCs and progenitors, and (4) attenuates the severity of SAA. Furthermore, prolonged treatment of developing SAA with LA1 has therapeutic effects since it not only attenuates the progression and severity of SAA, but also converts otherwise fatal SAA into a survivable disease in mouse SAA models. To begin to address mechanism for these findings we found that LA1 treatment significantly reduces the antigen presenting capacity and T cell activating capacity of DCs. Importantly, in vivo LA1 treatment significantly increases the population of regulatory T cells (Tregs) which may also contribute to the above effects of LA1 on SAA. Simultaneous targeting of multiple pathophysiological features of AA underscores the clinically relevant potential of LA1 treatment as a novel promising multi-target immunosuppressive therapy that can safely and efficiently attenuate the severity of AA and reduce the need for BMT. We are also further evaluating the potential of LA1 treatment combined with IST or in vivo Treg expansion approaches (low dose rIL-2 therapy) to safely and more effectively attenuate the progression and severity of AA in pre-clinical mouse SAA models. These studies will provide an important platform for further translational and clinical testing of LAs as: (1) New therapy to manage ongoing AA in patients who are not responding to IST and are not candidates for BMT, (2) New therapy for relapsed AA, and/or (3) Adjuvant therapy for AA patients who are undergoing IST and are awaiting BM transplant. Disclosures Levy: Allergan: Consultancy.

Tumor-Targeted Human CD4+ CD25hi Regulatory T Cells Effectively Inhibit T Cell –mediated Rejection of CD19+ Tumors in An in Vivo xenotransplant Tumor Model

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 3901-3901
Author(s):  
James Lee ◽  
Michel Sadelain ◽  
Renier J. Brentjens
Keyword(s):  
T Cells ◽  
T Cell ◽  
Regulatory T Cells ◽  
B Cell ◽  
Clinical Setting ◽  
Effector T Cells ◽  
Effector T Cell ◽  
Human T Cells ◽  
Anti Tumor Activity

Abstract The genetic targeting of human T cells to selected tumor antigens offers a novel means to investigate human immunobiology and treat cancer. T cells may be genetically modified to target specific antigens through the introduction of genes encoding chimeric antigen receptors (CARs). We have previously demonstrated that human T cells targeted in this manner to the CD19 antigen, expressed on normal B cells as well as most B cell tumors, eradicate systemic human CD19+ B cell malignancies in SCID-Beige mice. However, in the clinical setting, the anti-tumor efficacy of these T cells may be impaired by endogenous suppressive elements of the host immune system, including CD4+ CD25hi Foxp3+ regulatory T cells (Tregs). Significantly, Tregs are often increased in the blood and infiltrate the tumor of cancer patients which has been correlated with poor patient outcome and ineffective anti-tumor immunity. In order to study the in vivo impact of Tregs on adoptive therapy with CD19 targeted effector T cells, we developed a murine model wherein human Tregs, similarly targeted to the tumor, are infused prior to adoptive transfer of targeted cytotoxic T cells. To do so, we initially isolated natural Tregs from healthy donor peripheral blood mononuclear cells. Isolated Tregs were subsequently modified to express CARs through retroviral gene transfer. Subsequently, CAR+ Tregs were rapidly expanded either by activation on NIH-3T3 fibroblasts modified to express CD19 and the CD80 costimulatory ligand (3T3(CD19/CD80)), or non-specifically using CD3/CD28 antibodycoated magnetic beads. Expanded CAR+ Tregs exhibited potent suppressive function in vitro inhibiting both effector T cell proliferation as well as cytotoxicity. In vivo, CAR+ Tregs specifically traffic to established tumor in SCID-Beige mice. Significantly, injection of CD19-targeted Tregs into SCID-Beige mice bearing established human CD19+ tumors at 24 hours prior to infusion with CD19-targeted effector T cells, completely abrogated effector T cell function even at Treg:Teff ratios as low as 1:8. We further found that full suppression was dependant both on Treg localization to the tumor site as well as in vivo activation through the CAR. Finally, we show that a pre-conditioning regimen with low-dose cyclophosphamide, which failed to eradicate tumor, was able to reverse the CAR+ Treg mediated inhibition and restore the anti-tumor activity by the targeted effector T cells. In conclusion, we have developed a robust model ideally suited to the study of in vivo Treg-Teff interactions. Furthermore, the data generated from this model to date have significant implications with respect to the application of adoptive T cell therapies in the clinical setting. Namely, the presence of endogenous Tregs at the site of tumor is likely to significantly compromise the anti-tumor activity of adoptively transferred tumor targeted T cells. This inhibition may be reversed by preconditioning regimens designed to eradicate endogenous Tregs. The findings presented here should be considered in the design of future clinical trials utilizing T cell-based adoptive therapies of cancer.

Juzentaihoto Exerts Anti-Allergic Effects by Inhibiting Effector T-Cell Activation and Inducing and/or Activating Regulatory T Cells in a Murine Model of Contact Hypersensitivity

2021 ◽  
pp. 1-13
Author(s):  
Atsushi Tsuge ◽  
Sho Yonekura ◽  
Satomi Watanabe ◽  
Yuta Kurosaki ◽  
Shinsuke Hisaka ◽  
...  
Keyword(s):  
T Cells ◽  
Monoclonal Antibodies ◽  
T Cell ◽  
Regulatory T Cells ◽  
T Cell Activation ◽  
Cell Activation ◽  
Effector T Cells ◽  
Contact Hypersensitivity ◽  
Dependent Manner ◽  
Effector T Cell

<b><i>Background:</i></b> Juzentaihoto (JTT) is a Kampo prescription that has been used clinically for treating skin diseases such as atopic dermatitis in Japan. We have previously studied the anti-allergic effects of JTT on 2,4,6-trinitrochlorobenzene (TNCB)-induced contact hypersensitivity (CHS) in mice and demonstrated that it significantly suppresses ear swelling in a dose-dependent manner. However, the mechanism underlying the anti-allergic actions of JTT is obscure. <b><i>Methods:</i></b> We investigated the mechanism underlying the anti-allergic effects of JTT using a TNCB-induced murine CHS model and adoptive cell transfer experiments. <b><i>Results:</i></b> We showed that the anti-allergic effects of JTT are due to inhibition of effector T-cell activation and induction and/or activation of regulatory T cells. Furthermore, ex vivo experiments confirmed the effect of JTT on the activation of effector T cells and regulatory T cells, as interferon-γ production decreased, whereas interleukin (IL)-10 production increased, in the cultured lymphocytes obtained from 5% TNCB-sensitized mice treated with anti-CD3ε and anti-CD28 monoclonal antibodies. Flow cytometry showed that the CD4<sup>+</sup>CD25<sup>+</sup>Foxp3<sup>+</sup>, CD4<sup>+</sup>CD25<sup>+</sup>Foxp3<sup>−</sup>, and CD8<sup>+</sup>CD122<sup>+</sup> cell population increased after oral administration of JTT. Finally, the anti-allergic effect of JTT by inducing and/or activating regulatory T cells (Tregs) was confirmed to be mediated by IL-10 through in vivo neutralization experiments with anti-IL-10 monoclonal antibodies. <b><i>Conclusion:</i></b> We suggested that JTT exerts anti-allergic effects by regulating the activation of effector T cells and Tregs involved in murine CHS model.

Impact of Regulatory T Cells on Antigen Specific T Cell Response Using Recombinant Chimeric T Cell Receptors In Vivo.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 5475-5475
Author(s):  
David M. Kofler ◽  
Markus Chmielewski ◽  
Heike Koehler ◽  
Tobias Riet ◽  
Patrick Schmidt ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Regulatory T Cells ◽  
Tumor Cells ◽  
T Cell Receptors ◽  
Cell Response ◽  
Effector T Cells ◽  
T Cell Response ◽  
Cell Receptors

Abstract Recombinant T cell receptors with defined specificity against tumor cells are a promising experimental approach in the elimination of residual leukemia and lymphoma cells. It is so far unresolved whether regulatory T cells with suppressor activities impair the efficiency of cytolytic T cells grafted with a recombinant immunoreceptor. The frequency of regulatory T cells is highly increased in tumor patients and their suppressive function seems to play a role in the fail of an autologous T cell response against the malignant cells. In this study we analyzed the antigen-triggered, specific activation of receptor grafted T cells in the presence or absence of regulatory CD4+CD25high T cells. CD3+ T cells were grafted with CEA-specific immunoreceptors containing the CD3-zeta signaling domain for T cell activation. Co-cultivation of receptor grafted effector T cells together with regulatory T cells repressed proliferation of the effector cells and decreased IL-2 secretion. Secretion of IFN-gamma and IL-10 was not impaired. Interestingly, the cytotoxicity of grafted effector T cells towards CEA-expressing tumor cells was not impaired by regulatory T cells in vitro. To evaluate the relevance in vivo, we used a Crl:CD1 Nu/Nu mouse model to assess growth of CEA+ tumor cells in the presence of receptor grafted effector T cells and of regulatory T cells. Mice inoculated with tumor cells together with CD3+ effector T cells without immunoreceptor and regulatory T cells developed earlier tumors with faster growth kinetics compared to mice that were inoculated with tumor cells, CD3+ T cells and CD4+CD25- control T cells. Using effector T cells that were equipped with a recombinant CEA-specific CD3-zeta immunoreceptor, 2 of 5 mice developed a tumor in the presence of regulatory T cells while none of the mice developed a tumor in the absence of regulatory T cells. Taken together, regulatory T cells obviously impair an antigen-specific, anti-tumor T cell attack in vivo. This seems to be due to repression of proliferation of the effector T cells and not to diminished cytotoxicity. These findings have major impact on the design of clinical studies involving adoptively transferred effector T cells.

scholarly journals Direct demonstration of cytokine synthesis heterogeneity among human memory/effector T cells by flow cytometry

Blood ◽  
1995 ◽  
Vol 86 (4) ◽  
pp. 1408-1419 ◽  
Author(s):  
LJ Picker ◽  
MK Singh ◽  
Z Zdraveski ◽  
JR Treer ◽  
SL Waldrop ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Subset ◽  
Human Memory ◽  
Effector T Cells ◽  
Accessory Cell ◽  
Effector T Cell ◽  
Cytokine Synthesis

The array of cytokines produced by T cells in effector sites is a primary means by which these cells mediate host defense. It is well recognized that cloned T cells are heterogeneous with regard to cytokine synthesis and, thus, in their ability to mediate specific immune responses, but the extent to which the patterns of cytokine secretion observed in cloned cells reflect actual populations of memory/effector T cells existing in vivo is largely unknown. Here, we report our findings using a multiparameter flow cytometric assay that allows simultaneous determination of an individual T-cell' ability to produce multiple cytokines and its phenotype after only short (4 to 8 hours) in vitro incubation with an activating stimulus and the secretion inhibitor Brefeldin A. This assay shows a rapid accumulation of interleukin-2 (IL-2), IL-4, and gamma-interferon (gamma-IFN) in the cytoplasm of CD4+ cells after stimulation with either accessory cell- independent (phorbol 12-myristate 13-acetate [PMA] + ionomycin [I]) or accessory cell-dependent (staphylococcal enterotoxins [SE] A and B) T- cell-activating stimuli. Further analysis showed that production of gamma-IFN and IL-4 is predominantly, if not exclusively, restricted to the CD45ROhigh memory/effector T-cell subset, whereas IL-2 may be produced by both the CD45ROhigh and CD45ROlow subsets. Simultaneous determination of IL-2 and gamma-IFN production among CD45ROhigh/CD4+ T cells showed distinct subsets that produce each of these cytokines alone (an average of 30% for IL-2 alone, 8% for gamma-IFN alone), both (16%), or neither (46%). Similar analyses with the small IL-4-producing memory/effector T-cell subset (only 4.3% of total CD4+/CD45ROhigh T cells) showed that an average of 51% of these IL-4-producing cells also synthesize average of 51% of these IL-4-producing cells also synthesize IL-2, 23% synthesize only IL-4, 16% synthesize all three cytokines, and 9.6% synthesize IL-4 and gamma-IFN. These patterns of cytokine synthesis were found to be similar with both PMA + I and SEA/SEB stimulation and were observed in both peripheral blood memory/effector CD4+ T cells and in T cells of similar phenotype obtained from cutaneous delayed-type hypersensitivity sites. Taken together, these data strongly support the in vivo existence of human memory/effector T- cell subsets with “preprogrammed” cytokine synthesis potential, although they suggest that these subsets may be more complex than originally proposed in the TH1/TH2 hypothesis.

Regulatory T-cells and cAMP suppress effector T-cells independently of PKA–CREM/ICER: a potential role for Epac

2013 ◽  
Vol 456 (3) ◽  
pp. 463-473 ◽  
Author(s):  
Amanda G. Vang ◽  
William Housley ◽  
Hongli Dong ◽  
Chaitali Basole ◽  
Shlomo Z. Ben-Sasson ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Regulatory T Cells ◽  
Regulatory T Cell ◽  
Potential Role ◽  
Cell Function ◽  
Effector T Cells ◽  
Immune Control ◽  
Effector T Cell ◽  
Camp Signalling

Immune control of effector T-cell function can be mediated by cAMP signalling and regulatory T-cell action independently of the PKA–CREM/ICER signalling pathway. EPAC may act as an alternative cAMP effector in this process.

scholarly journals In vivo sites and cellular mechanisms of T reg cell–mediated suppression

2006 ◽  
Vol 203 (3) ◽  
pp. 489-492 ◽  
Author(s):  
Alexander Y. Rudensky ◽  
Daniel J. Campbell
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
T Cell Activation ◽  
Cell Activation ◽  
Effector T Cells ◽  
Cell Contact ◽  
Cellular Mechanisms ◽  
Effector T Cell

Regulatory CD4 T (T reg) cells control immune responses to self-antigens and pathogens. However, where T reg cells act to curtail effector T cells in vivo and what stage of effector T cell activation or differentiation is targeted by T reg cells remain unknown. Furthermore, a requirement for direct effector T cell–T reg cell contact in vivo has not been ascertained. Varying answers to these important questions have been provided by several new studies.

scholarly journals Fluvastatin-Pretreated Donor Cells Attenuated Murine aGVHD by Balancing Effector T Cell Distribution and Function under the Regulation of KLF2

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Kai Zhao ◽  
Yu Tian ◽  
Junjie Wang ◽  
Chong Chen ◽  
Bin Pan ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Effector T Cells ◽  
Lymphoid Organs ◽  
Protective Effects ◽  
Hematopoietic Stem ◽  
Effector T Cell ◽  
Donor Cells

Prevention of acute graft-versus-host disease (aGVHD) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) is still to be explored. Statins are potent immunomodulatory agents that hold promise as novel and safe agents for aGVHD prophylaxis, yet the controversial effect and regulatory mechanism are incompletely understood. Here, in an MHC mismatched murine model, we found that Fluvastatin-pretreated donor cells could attenuate aGVHD severity by remission tissue pathological injury. Fluvastatin served to restrain effector T cells entry into aGVHD target organs from secondary lymphoid organs (SLOs). The potential mechanism of correcting the effector T cell biased distribution was that Fluvastatin elevated CD62L and CCR7 expression while decreased CXCR3 and CD44 levels, which were correlated with Kruppel-like factor 2 (KLF2) sustention in donor-derived cells. In addition, Fluvastatin was contributed to reducing cytokines IFN-γ, TNF-α, and granzyme-B production in allogeneic effector CD4+ and CD8+ T cells. Furthermore, evidence confirmed that Fluvastatin had a long-lasting effect to sustain KLF2 expression both in vitro and in vivo even under the stimulated circumstance. In conclusion, administration of Fluvastatin to donor mice showed protective effects against recipient aGVHD when compared to untreated mice due to the retention of effector T cells in lymphoid organs accompanying with reduction of nonlymphatic infiltration and related inflammatory cytokines.

scholarly journals Regulatory T Cells Fail to Suppress Fast Homeostatic Proliferation In Vitro

Life ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 245
Author(s):  
Daniil Shevyrev ◽  
Valeriy Tereshchenko ◽  
Elena Blinova ◽  
Nadezda Knauer ◽  
Ekaterina Pashkina ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
T Cells ◽  
T Cell ◽  
Regulatory T Cells ◽  
Autoimmune Diseases ◽  
Peripheral Blood ◽  
Treg Cells ◽  
Homeostatic Proliferation ◽  
Suppressive Activity ◽  
Healthy Donors

Homeostatic proliferation (HP) is a physiological process that reconstitutes the T cell pool after lymphopenia involving Interleukin-7 and 15 (IL-7 and IL-15), which are the key cytokines regulating the process. However, there is no evidence that these cytokines influence the function of regulatory T cells (Tregs). Since lymphopenia often accompanies autoimmune diseases, we decided to study the functional activity of Tregs stimulated by HP cytokines from patients with rheumatoid arthritis as compared with that of those from healthy donors. Since T cell receptor (TCR) signal strength determines the intensity of HP, we imitated slow HP using IL-7 or IL-15 and fast HP using a combination of IL-7 or IL-15 with anti-CD3 antibodies, cultivating Treg cells with peripheral blood mononuclear cells (PBMCs) at a 1:1 ratio. We used peripheral blood from 14 patients with rheumatoid arthritis and 18 healthy volunteers. We also used anti-CD3 and anti-CD3 + IL-2 stimulation as controls. The suppressive activity of Treg cells was evaluated in each case by the inhibition of the proliferation of CD4+ and CD8+ cells. The phenotype and proliferation of purified CD3+CD4+CD25+CD127lo cells were assessed by flow cytometry. The suppressive activity of the total pool of Tregs did not differ between the rheumatoid arthritis and healthy donors; however, it significantly decreased in conditions close to fast HP when the influence of HP cytokines was accompanied by anti-CD3 stimulation. The Treg proliferation caused by HP cytokines was lower in the rheumatoid arthritis (RA) patients than in the healthy individuals. The revealed decrease in Treg suppressive activity could impact the TCR landscape during lymphopenia and lead to the proliferation of potentially self-reactive T cell clones that are able to receive relatively strong TCR signals. This may be another explanation as to why lymphopenia is associated with the development of autoimmune diseases. The revealed decrease in Treg proliferation under IL-7 and IL-15 exposure can lead to a delay in Treg pool reconstitution in patients with rheumatoid arthritis in the case of lymphopenia.

scholarly journals H-2 restriction of virus-specific T-cell-mediated effector functions in vivo. II. Adoptive transfer of delayed-type hypersensitivity to murine lymphocytic choriomeningits virus is restriced by the K and D region of H-2.

1976 ◽  
Vol 144 (3) ◽  
pp. 776-787 ◽  
Author(s):  
R M Zinkernagel
Keyword(s):  
T Cells ◽  
T Cell ◽  
Adoptive Transfer ◽  
Gamma Globulin ◽  
Effector T Cells ◽  
Delayed Type Hypersensitivity ◽  
T Effector Cells ◽  
Immune Lymphocytes ◽  
D Region

In mice, primary footpad swelling after local infection with lymphocytic choriomeningitis virus (LCMV) and delayed-type hypersensitivity (DTH) adoptively transferred by LCMV immune lymphocytes are T-cell dependent. Nude mice do not develop primary footpad swelling, and T-cell depletion abrogates the capacity to transfer LCMV-specific DTH. Effector T cells involved in eliciting dose-dependent DTH are virus specific in that vaccinia virus-immune lymphocytes could not elicit DTH in LCMV-infected mice. The adoptive transfer of DTH is restricted to H-2K or H-2D compatible donor-recipient combinations. Distinct from the fowl-gamma-globulin DTH model, I-region compatibility is neither necessary nor alone sufficient. Whatever the mechanisms involved in this K- or D-region associated restriction in vivo, it most likely operates at the level of T-cell recognition of "altered self" coded in K or D. T cells associated with the I region (helper T cells and DTH-T cells to fowl-gamma-globulin) are specific for soluble, defined, and inert antigens. T cells associated with the K and D region (T cells cytotoxic in vitro and in vivo for acute LCMV-infected cells, DTH effector T cells, and anti-viral T cells) are specific for infectious, multiplying virus. The fact that T-cell specificity is differentially linked with the I region or with the K and D regions of H-2 may reflect the fundamental biological differences of these antigens. Although it cannot be excluded that separate functional subclasses of T-effector cells could have self-recognizers for different cell surface structures coded in I or K and D, it is more likely that the antigen parameters determine whether T cells are specific for "altered" I or "altered" K- or D-coded structures.

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