Depletion of radio-resistant regulatory T cells enhances antitumor immunity during recovery from lymphopenia

Abstract Cytotoxic lymphodepletion therapies augment antitumor immune responses. The generation and therapeutic efficacy of antitumor effector T cells (TEs) are enhanced during recovery from lymphopenia. Although the effects of lymphodepletion on naive T cells (TNs) and TEs have been studied extensively, the influence of lymphodepletion on suppressor cells remains poorly understood. In this study, we demonstrate a significant increase of CD4+CD25+Foxp3+ regulatory T cells (Tregs) in sublethally irradiated lymphopenic mice. These radio-resistant Tregs inhibited the induction of TEs in tumor-draining lymph-nodes (TDLNs) during recovery from lymphopenia. The transfer of TNs into lymphopenic tumor-bearing mice resulted in some antitumor effects; however, Treg depletion after whole-body irradiation and reconstitution strongly inhibited tumor progression. Further analyses revealed that tumor-specific T cells were primed from the transferred TNs, whereas the Tregs originated from irradiated recipient cells. As in irradiated lymphopenic mice, a high percentage of Tregs was observed in cyclophosphamide-treated lymphopenic mice. The inhibition of Tregs in cyclophosphamide-treated mice significantly reduced tumor growth. These results indicate that the Tregs that survive cytotoxic therapies suppress antitumor immunity during recovery from lymphopenia and suggest that approaches to deplete radio and chemo-resistant Tregs can enhance cancer immunotherapies.

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Japanese Kampo Medicine Juzentaihoto Enhances Antitumor Immunity in CD1d−/− Mice Lacking NKT Cells

Integrative Cancer Therapies ◽

10.1177/1534735419900798 ◽

2020 ◽

Vol 19 ◽

pp. 153473541990079

Author(s):

Shun Takaku ◽

Masumi Shimizu ◽

Hidemi Takahashi

Keyword(s):

T Cells ◽

Tumor Growth ◽

Antitumor Immunity ◽

Suppressor Cells ◽

Tumor Model ◽

Nkt Cells ◽

Kampo Medicine ◽

Myeloid Derived Suppressor Cells ◽

Antitumor Effects

Although the Japanese traditional herbal medicine (Kampo), Juzentaihoto (JTT), has been reported to have antitumor effects in several tumor models, its role in tumor immunology remains controversial. In the present study, we tested whether oral administration of JTT enhances antitumor immunity in CD1d−/− mice, in which immunosuppression was partially relieved due to the lack of NKT cells. In a subcutaneous murine syngeneic CT26 colorectal tumor model, JTT had no impact on tumor growth in wild type (WT) BALB/c mice. However, the growth rate of tumors was significantly slower in CD1d−/− mice than in WT mice. Surprisingly, JTT significantly delayed tumor growth in such CD1d−/− mice. In vivo depletion of CD8+ T cells revealed that CD8+ T cells are required for JTT’s antitumor activity. Moreover, tumor-reactive cytotoxic T-lymphocytes were detected exclusively in JTT-treated mice with well-controlled tumors. JTT did not affect the number of tumor-infiltrating CD4+ regulatory T cells. On the contrary, JTT increased the degranulation marker CD107a+ CD8+ T cells and decreased Ly6G+ Ly6Clo polymorphonuclear myeloid-derived suppressor cells in tumor-infiltrating lymphocytes, most probably contributing to the suppression of tumor growth in JTT-treated mice. Nonetheless, JTT had no impact on the proportion of monocytic myeloid-derived suppressor cells. In conclusion, our results indicate that in the absence of NKT cells, JTT augments antitumor immunity by CD8+ T cells, suggesting that this Kampo medicine is a promising anticancer adjuvant when negative immune regulation is partially relieved.

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Monoclonal antibody blockade of IL-2 receptor α during lymphopenia selectively depletes regulatory T cells in mice and humans

Blood ◽

10.1182/blood-2011-02-334565 ◽

2011 ◽

Vol 118 (11) ◽

pp. 3003-3012 ◽

Cited By ~ 64

Author(s):

Duane A. Mitchell ◽

Xiuyu Cui ◽

Robert J. Schmittling ◽

Luis Sanchez-Perez ◽

David J. Snyder ◽

...

Keyword(s):

Monoclonal Antibody ◽

T Cells ◽

Regulatory T Cells ◽

Immune Responses ◽

Adoptive Cell Transfer ◽

Antitumor Efficacy ◽

Treg Depletion ◽

Synergistic Enhancement ◽

Antitumor Effector ◽

Clinical Responses

Abstract Lymphodepletion augments adoptive cell transfer during antitumor immunotherapy, producing dramatic clinical responses in patients with malignant melanoma. We report that the lymphopenia induced by the chemotherapeutic agent temozolomide (TMZ) enhances vaccine-driven immune responses and significantly reduces malignant growth in an established model of murine tumorigenesis. Unexpectedly, despite the improved antitumor efficacy engendered by TMZ-induced lymphopenia, there was a treatment related increase in the frequency of immunosuppressive regulatory T cells (TRegs; P = .0006). Monoclonal antibody (mAb)–mediated inhibition of the high-affinity IL-2 receptor α (IL-2Rα/CD25) during immunotherapy in normal mice depleted TRegs (73% reduction; P = .0154) but also abolished vaccine-induced immune responses. However, during lymphodepletion, IL-2Rα blockade decreased TRegs (93% reduction; P = .0001) without impairing effector T-cell responses, to augment therapeutic antitumor efficacy (66% reduction in tumor growth; P = .0024). Of clinical relevance, we also demonstrate that anti–IL-2Rα mAb administration during recovery from lymphodepletive TMZ in patients with glioblastoma reduced TReg frequency (48% reduction; P = .0061) while permitting vaccine-stimulated antitumor effector cell expansion. To our knowledge, this is the first report of systemic antibody-mediated TReg depletion during lymphopenia and the consequent synergistic enhancement of vaccine-driven cellular responses, as well as the first demonstration that anti–IL-2Rα mAbs function differentially in nonlymphopenic versus lymphopenic contexts.

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Iron Released after Cryo-Thermal Therapy Induced M1 Macrophage Polarization, Promoting the Differentiation of CD4+ T Cells into CTLs

International Journal of Molecular Sciences ◽

10.3390/ijms22137010 ◽

2021 ◽

Vol 22 (13) ◽

pp. 7010

Author(s):

Shicheng Wang ◽

Man Cheng ◽

Peng Peng ◽

Yue Lou ◽

Aili Zhang ◽

...

Keyword(s):

T Cells ◽

Cd4 T Cells ◽

Antitumor Immunity ◽

Macrophage Polarization ◽

Thermal Therapy ◽

High Plasticity ◽

Antitumor Effects ◽

M1 Macrophages ◽

Splenic Macrophages ◽

M1 Macrophage

Macrophages play critical roles in both innate and adaptive immunity and are known for their high plasticity in response to various external signals. Macrophages are involved in regulating systematic iron homeostasis and they sequester iron by phagocytotic activity, which triggers M1 macrophage polarization and typically exerts antitumor effects. We previously developed a novel cryo-thermal therapy that can induce the mass release of tumor antigens and damage-associated molecular patterns (DAMPs), promoting M1 macrophage polarization. However, that study did not examine whether iron released after cryo-thermal therapy induced M1 macrophage polarization; this question still needed to be addressed. We hypothesized that cryo-thermal therapy would cause the release of a large quantity of iron to augment M1 macrophage polarization due to the disruption of tumor cells and blood vessels, which would further enhance antitumor immunity. In this study, we investigated iron released in primary tumors, the level of iron in splenic macrophages after cryo-thermal therapy and the effect of iron on macrophage polarization and CD4+ T cell differentiation in metastatic 4T1 murine mammary carcinoma. We found that a large amount of iron was released after cryo-thermal therapy and could be taken up by splenic macrophages, which further promoted M1 macrophage polarization by inhibiting ERK phosphorylation. Moreover, iron promoted DC maturation, which was possibly mediated by iron-induced M1 macrophages. In addition, iron-induced M1 macrophages and mature DCs promoted the differentiation of CD4+ T cells into the CD4 cytolytic T lymphocytes (CTL) subset and inhibited differentiation into Th2 and Th17 cells. This study explains the role of iron in cryo-thermal therapy-induced antitumor immunity from a new perspective.

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Proteolysis-targeting chimera against BCL-XL destroys tumor-infiltrating regulatory T cells

Nature Communications ◽

10.1038/s41467-021-21573-x ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Ryan Kolb ◽

Umasankar De ◽

Sajid Khan ◽

Yuewan Luo ◽

Myung-Chul Kim ◽

...

Keyword(s):

T Cells ◽

Regulatory T Cells ◽

Cell Lymphoma ◽

B Cell Lymphoma ◽

Molecular Target ◽

Therapeutic Strategies ◽

Normal Tissues ◽

Effective Suppression ◽

Immunosuppressive Microenvironment ◽

Cancer Immunotherapies

AbstractRegulatory T cells (Tregs) play an important role in maintaining immune homeostasis and, within tumors, their upregulation is common and promotes an immunosuppressive microenvironment. Therapeutic strategies that can eliminate Tregs in the tumor (i.e., therapies that do not run the risk of affecting normal tissues), are urgently needed for the development of cancer immunotherapies. Here we report our discovery of B-cell lymphoma extra-large (BCL-XL) as a potential molecular target of tumor-infiltrating (TI) Tregs. We show that pharmacological degradation of BCL-XL using a newly developed platelet-sparing BCL-XL Proteolysis-targeting chimera (PROTAC) induces the apoptosis of TI-Tregs and the activation of TI-CD8+ T cells. Moreover, these activities result in an effective suppression of syngeneic tumor growth in immunocompetent, but not in immunodeficient or CD8+ T cell-depleted mice. Notably, treatment with BCL-XL PROTAC does not cause detectable damage within several normal tissues or thrombocytopenia. These findings identify BCL-XL as a target in the elimination of TI-Tregs as a component of cancer immunotherapies, and that the BCL-XL-specific PROTAC has the potential to be developed as a therapeutic for cancer immunotherapy.

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Identification of CD4+CD25+CD127− regulatory T cells and CD14+HLA−DR−/low myeloid-derived suppressor cells and their roles in the prognosis of breast cancer

Biomedical Reports ◽

10.3892/br.2016.694 ◽

2016 ◽

Vol 5 (2) ◽

pp. 208-212 ◽

Cited By ~ 9

Author(s):

Jinhu Wang ◽

Jianhong Yang

Keyword(s):

Breast Cancer ◽

T Cells ◽

Regulatory T Cells ◽

Suppressor Cells ◽

Myeloid Derived Suppressor Cells ◽

Hla Dr

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IL-36γ-armed oncolytic virus exerts superior efficacy through induction of potent adaptive antitumor immunity

Cancer Immunology Immunotherapy ◽

10.1007/s00262-021-02860-4 ◽

2021 ◽

Author(s):

Min Yang ◽

Esther Giehl ◽

Chao Feng ◽

Mathilde Feist ◽

Hongqi Chen ◽

...

Keyword(s):

T Cells ◽

Therapeutic Efficacy ◽

Oncolytic Virus ◽

Antitumor Immunity ◽

Human Cancer ◽

Suppressor Cells ◽

T Cell Differentiation ◽

Effector Cells ◽

Superior Efficacy ◽

Vaccinia Viruses

AbstractIn this study, we aimed to apply the cytokine IL-36γ to cancer immunotherapy by constructing new oncolytic vaccinia viruses (OV) expressing interleukin-36γ (IL-36γ-OVs), leveraging unique synergism between OV and IL-36γ’s ability to promote antitumor adaptive immunity and modulate tumor microenvironment (TME). IL-36γ-OV had dramatic therapeutic efficacies in multiple murine tumor models, frequently leading to complete cancer eradication in large fractions of mice. Mechanistically, IL-36-γ-armed OV induced infiltration of lymphocytes and dendritic cells, decreased myeloid-derived suppressor cells and M2-like tumor-associated macrophages, and T cell differentiation into effector cells. Further study showed that IL-36γ-OV increased the number of tumor antigen-specific CD4+ and CD8+ T cells and the therapeutic efficacy depended on both CD8+ and CD4+ T cells. These results demonstrate that these IL36γ-armed OVs exert potent therapeutic efficacy mainly though antitumor immunity and they may hold great potential to advance treatment in human cancer patients.

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231 Molecular insights on safety and anti-tumor activity of a non-irAE-inducing anti-CTLA-4 monoclonal antibody ONC-392

Journal for ImmunoTherapy of Cancer ◽

10.1136/jitc-2021-sitc2021.231 ◽

2021 ◽

Vol 9 (Suppl 3) ◽

pp. A246-A246

Author(s):

Yang Liu ◽

Yan Zhang ◽

Xuexiang Du ◽

Mingyue Liu ◽

Xianfeng Fang ◽

...

Keyword(s):

T Cells ◽

Regulatory T Cells ◽

Cell Surface ◽

Cancer Immunotherapy ◽

Immune Tolerance ◽

Ph Sensitive ◽

Clinical Testing ◽

Wild Type ◽

Treg Depletion ◽

Anti Tumor Activity

BackgroundAnti-CTLA-4 antibodies have brought about limited clinical benefit because severe toxicity limits dosing levels and/or duration. We used CTLA-4 knockin mice to screen for antibodies with higher anti-tumor activity but lower autoimmunity. We have revealed that the key for better safety and preclinical efficacy is preservation of CTLA-4 for immune tolerance and intratumorial Treg depletion. Our work established that, independent of blocking activities, mAbs that preserve CTLA-4 recycling maintain the physiological immune tolerance checkpoint function while allowing more efficient and selective elimination of tumor-infiltrating regulatory T cells, resulting in highest efficacy and lowest toxicity and was thus developed for clinical testing of all antibodies tested.1–6 The antibody with best safety and efficacy profile, ONC-392 was developed for clinical testing. The first-in human studies showed that ONC-392 is safe and well tolerated. Remarkably, no irAE has been reported among patients who has received repeated dosing of 3.0 mg/kg and 10.0 mg/kg of ONC-392. The molecular and cellular characterization of ONC-392 will be presented.MethodsIn vitro binding and disassociation assay were determined between pH 4.0–7.0. The intracellular traffic of both antibodies and CTLA-4 molecules were visualized by confocal microscopy. The binding to human and mouse FcgRI, IIA, IIB, and III (A), FcRn as well as mouse FcgRIV were evaluated by surface plasmon resonance (SPR). Depletion of regulatory T cells in tumor and lymphoid tissues were determined by flow cytometry.ResultsONC-392 is a pH-sensitive antibody that preserves CTLA-4 recycling. By preserving cell surface CTLA-4, Onco-392 preserves immune tolerance. Preserving CTLA-4 on tumor-infiltrating Treg contribute to more effective immunotherapy. In addition to its unique feature of pH sensitive binding, OncoC4 also have several important features in Fc. ONC-392 shown comparable binding to human FcgRI and IIIA as wild-type IgG1s. As expected from the mutations introduced, ONC-392 show about 6 fold higher affinity for FcRn than wild-type IgG1. Interestingly, ONC-392 has shown 7–10-fold reduction to FcgRIIB, which is generally considered to be a negative signaling FcR. ONC-392 binding to mouse FcgRI-IV was lower that WT IgG1.ConclusionsUnlike other clinical anti-CTLA-4 antibodies, ONC-392 preserves CTLA-4 recycling and thus Treg function in the peripheral tissues. The higher cell surface CTLA-4 allows more efficient Treg depletion in the tumor microenvironment. In addition, despite reduced binding to mouse activating Fc?RI, III/IV, ONC-392 was more effective in intratumor Treg depletion in the mice. Therefore, lacking negative signaling from Fc?RIIB may also contribute to its anti-tumor activity.Trial RegistrationNCT04140526ReferencesDu X, et al. Uncoupling therapeutic from immunotherapy-related adverse effects for safer andeffective anti-CTLA-4 antibodies in CTLA4 humanized mice. Cell Res 2018;28:433–447.Du X, et al. A reappraisal of CTLA-4 checkpoint blockade in cancer immunotherapy. Cell Res 2018;28:416–432.Liu Y, Zheng P. How does an anti-CTLA-4 antibody promote cancer immunity? Trends Immunol 2018;39:953–956.Zhang Y, et al. Hijacking antibody-induced CTLA-4 lysosomal degradation for safer and more effective cancer immunotherapy. Cell Res 2019;29:609–627.Liu Y, Zheng P. Preserving the CTLA-4 checkpoint for safer and more effective cancer immunotherapy. Trends Pharmacol Sci 2020;41(1):4–12.Zhang P, et al. Mechanism- and immune landscape-based ranking of therapeutic responsiveness of 22 major human cancers to next generation anti-CTLA-4 antibodies. Cancers 2020;12:284.

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Kidney GATA3+ regulatory T cells play roles in the convalescence stage after antibody-mediated renal injury

Cellular and Molecular Immunology ◽

10.1038/s41423-020-00547-x ◽

2020 ◽

Author(s):

Ryota Sakai ◽

Minako Ito ◽

Kyoko Komai ◽

Mana Iizuka-Koga ◽

Kazuhiko Matsuo ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Regulatory T Cells ◽

Disease Control ◽

Renal Injury ◽

Disease Onset ◽

Renal Tissue ◽

Tissue Destruction ◽

Treg Depletion ◽

Pparγ Agonist

Abstract FoxP3+ regulatory T cells (Tregs) play crucial roles in peripheral immune tolerance. In addition, Tregs that reside or accumulate in nonlymphoid tissues, called tissue Tregs, exhibit tissue-specific functions and contribute to the maintenance of tissue homeostasis and repair. In an experimental mouse model of crescentic glomerulonephritis induced by an anti-glomerular basement membrane antibody, Tregs started to accumulate in the kidney on day 10 of disease onset and remained at high levels (~30–35% of CD4+ T cells) during the late stage (days 21–90), which correlated with stable disease control. Treg depletion on day 21 resulted in the relapse of renal dysfunction and an increase in Th1 cells, suggesting that Tregs are essential for disease control during the convalescence stage. The Tregs that accumulated in the kidney showed tissue Treg phenotypes, including high expression of GATA3, ST2 (the IL33 receptor subunit), amphiregulin (Areg), and PPARγ. Although T-bet+ Tregs and RORγt+ Tregs were observed in the kidney, GATA3+ Tregs were predominant during the convalescence stage, and a PPARγ agonist enhanced the accumulation of GATA3+ Tregs in the kidney. To understand the function of specific genes in kidney Tregs, we developed a novel T cell transfer system to T cell-deficient mice. This experiment demonstrates that ST2, Areg, and CCR4 in Tregs play important roles in the accumulation of GATA3+ Tregs in the kidney and in the amelioration of renal injury. Our data suggest that GATA3 is important for the recruitment of Tregs into the kidney, which is necessary for convalescence after renal tissue destruction.

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