scholarly journals 778 Modulating tumor microenvironment with arginase-1 specific T cells

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A813-A813
Author(s):  
Evelina Martinenaite ◽  
Mia Aaboe Jørgensen ◽  
Rasmus Erik Johansson Mortensen ◽  
Shamaila Munir Ahmad ◽  
Stine Emilie Weis-Banke ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Tumor Microenvironment ◽  
Memory T Cells ◽  
Ethics Committee ◽  
Mouse Tumor ◽  
Immune Modulators ◽  
Arginase 1 ◽  
Mouse Tumor Models

BackgroundIO112 is an immune modulatory cancer therapy under preclinical development to target arginase-1-expressing tumor cells and immune inhibitory myeloid cells, such as myeloid derived suppressor cells (MDSCs), and tumor associated macrophages (TAMs). Arginase-1 acts as a metabolic immune regulator at the tumor site by reducing availability of L-arginine to the infiltrating immune cells thus reducing T cell functionality and proliferation. Previously, we demonstrated that IO112 triggers activation of spontaneous CD4+ and CD8+ T-cell responses against arginase-1, found in both cancer patients and healthy individuals.1 These T cells are present in the memory T cell compartment, and are activated in arginase-1 inducing conditions, such as presence of TH2 cytokines IL-4 or IL-13 in vitro.2 3 In this study we aimed to explore the role of arginase-1-specific T cells as immune modulators in immune homeostasis and tumor microenvironment for the development of IO112 immunomodulatory therapy.MethodsHuman arginase-1-specific T cells were isolated and expanded for functional characterization of reactivity against arginase-1 expressing target cells as well as subsequent phenotyping of the targeted arginase-1 positive cells. Syngeneic C57BL/6 mouse tumor models were used to assess the therapeutic efficacy of IO112.ResultsWe show that arginase-1-specific memory T cells specifically recognize arginase-1 expressing cells, such as mRNA transfected autologous dendritic cells (DCs) and B cells as well as M2 polarized macrophages in vitro. In addition, activated arginase-1-specific T cells produce pro-inflammatory cytokines IFNγ and TNFα. Secretion of TH1 cytokines by these T cells suggests that they may act as potent immune modulators in the tumor microenvironment, since many arginase-1 expressing myeloid cells are not terminally differentiated and they can be re-polarized to an immunostimulatory, M1-like phenotype. We also observed that targeting of M2-polarized arginase-1 expressing monocytic leukemia cell line THP-1 with arginase-1-specific CD4+ T cells induces upregulation of PD-L1 on the THP-1 cells. Furthermore, we demonstrate anti-tumor activity of IO112 in syngeneic mouse tumor models (B16 and MC38), both as monotherapy and in combination with anti-PD-1 treatment. The therapeutic effect was associated with increased immune infiltration in the IO112-treated mice compared to the control.ConclusionsWe demonstrate that arginase-1 specific T cells can influence the polarization of arginase-1-expressing immune cells. Our study provides evidence that IO112 immune therapy against arginase-1 is an attractive way of modulating the immune suppressive tumor microenvironment for therapeutic benefit. With this rationale, we are currently undertaking Investigational New Drug (IND) application enabling studies to explore this approach in a clinical setting.ReferencesMartinenaite E, Mortensen REJ, Hansen M, Holmström MO, Ahmad SM, Jørgensen NGD, Met Ö, Donia M, Svane IM, Andersen MH. Frequent adaptive immune responses against arginase-1. Oncoimmunology 2018;7(3):e1404215.Martinenaite E, Ahmad SM, Svane IM, Andersen MH. Peripheral memory T cells specific for Arginase-1. Cell Mol Immunol 2019;16(8):718–719.Martinenaite E, Ahmad SM, Bendtsen SK, Jørgensen MA, Weis-Banke SE, Svane IM, Andersen MH. Arginase-1-based vaccination against the tumor microenvironment: the identification of an optimal T-cell epitope. Cancer Immunol Immunother 2019;68(11):1901–1907.Ethics ApprovalThis study was approved by the Scientific Ethics Committee for The Capital Region of Denmark and Danish Ethics Committee on experimental animal welfare.

scholarly journals P04.05 Modulating tumor microenvironment with arginase-1 specific T cells

2020 ◽  
Vol 8 (Suppl 2) ◽  
pp. A38.2-A39
Author(s):  
E Martinenaite ◽  
M Aaboe Joergensen ◽  
RE Johansson Mortensen ◽  
S Munir Ahmad ◽  
SE Weis-Banke ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Tumor Microenvironment ◽  
Therapeutic Effect ◽  
Potential Role ◽  
Myeloid Cells ◽  
Tumor Site ◽  
Arginase 1 ◽  
Part Time

BackgroundCancer progression is associated with an increased immune suppression at the tumor site. Arginase-1 is an enzyme well-known for its involvement in metabolic immune regulation. At the tumor site, arginase-1 acts by reducing availability of L-arginine to the infiltrating immune cells thus reducing T cell functionality and proliferation. While arginase-1 is expressed by some tumor cells, it has also been shown to be produced by immune inhibitory myeloid cells, such as myeloid derived suppressor cells (MDSCs), tumor associated macrophages (TAMs) and is associated with poor prognosis. Previously, we demonstrated that spontaneous CD4+ and CD8+ T-cell immune responses against arginase-derived, HLA-restricted peptides can be found in both cancer patients and healthy individuals (Martinenaite et al, 2018, DOI: 10.1080/2162402X.2017.1404215). These T cells are present in the memory T cell compartment, and that they are activated in arginase-1 inducing conditions, such as presence of TH2 cytokines IL-4 or IL-13 in vitro (Martinenaite et al, 2019, DOI: 10.1038/s41423-019-0231-3 and DOI: 10.1007/s00262-019-02425-6).Methods and ResultsIn order to explore if arginase-1-specific T cells have a potential role in modulation of immune homeostasis, human arginase-1-specific memory T cells were isolated and expanded for functional characterization. We show that arginase-1-specific T cells specifically recognize arginase-1 expressing cells, such as mRNA transfected autologous dendritic cells (DCs) and B cells as well as M2 polarized macrophages in vitro. In addition, activated arginase-1-specific T cells produce pro-inflammatory cytokines IFNγ and TNFα. Secretion of TH1 cytokines by these T cells suggests potential role as potent immune modulators in the tumor microenvironment, since many arginase-1 expressing myeloid cells are not terminally differentiated and they can be re-polarized to an immunostimulatory, M1-like phenotype. We also observed that targeting of M2-polarized arginase-1 expressing monocytic leukemia cell line THP-1 with arginase-1-specific CD4+ T cells induces upregulation of PD-L1 on the THP-1 cells. Furthermore, we demonstrate that an arginase-1-derive peptide vaccine has a therapeutic effect in syngeneic mouse tumor models (B16 and MC38), both as monotherapy and in combination with anti-PD-1 treatment. The therapeutic effect was associated with increased immune infiltration in the peptide vaccinated mice compared to the control.ConclusionsOur study provides evidence that immune modulatory vaccination targeting arginase-1 is an intriguing way of targeting the immune suppressive microenvironment.Disclosure InformationE. Martinenaite: A. Employment (full or part-time); Significant; IO Biotech. M. Aaboe Joergensen: None. R.E. Johansson Mortensen: None. S. Munir Ahmad: None. S.E. Weis-Banke: None. M. Orebo Holmström: None. A. Wakatsuki Pedersen: A. Employment (full or part-time); Significant; IO Biotech. Ö. Met: None. I.M. Svane: F. Consultant/Advisory Board; Significant; IO Biotech. M. Hald Andersen: A. Employment (full or part-time); Significant; IO Biotech.

scholarly journals Hepatic Stellate Cells Enhance Liver Cancer Progression by Inducing Myeloid-Derived Suppressor Cells through Interleukin-6 Signaling

2019 ◽  
Vol 20 (20) ◽  
pp. 5079 ◽  
Author(s):  
Ching-Chuan Hsieh ◽  
Chien-Hui Hung ◽  
Meihua Chiang ◽  
Yu-Chin Tsai ◽  
Jie-Teng He
Keyword(s):  
T Cells ◽  
T Cell ◽  
Tumor Microenvironment ◽  
Hepatic Stellate Cells ◽  
Suppressor Cells ◽  
Stellate Cells ◽  
Myeloid Derived Suppressor Cells ◽  
Term Survival ◽  
Arginase 1

The tumor microenvironment, which consists of fibroblasts, smooth muscle cells, endothelial cells, immune cells, epithelial cells, and extracellular matrices, plays a crucial role in tumor progression. Hepatic stellate cells (HSCs), a class of unique liver stromal cells, participate in immunomodulatory activities by inducing the apoptosis of effector T-cells, generation of regulatory T-cells, and development of myeloid-derived suppressor cells (MDSCs) to achieve long-term survival of islet allografts. This study provides in vitro and in vivo evidences that HSCs induce the generation of MDSCs to promote hepatocellular carcinoma (HCC) progression through interleukin (IL)-6 secretion. HSC-induced MDSCs highly expressed inducible nitric oxide synthase (iNOS) and arginase 1 mRNA and presented potent inhibitory T-cell immune responses in the tumor environment. Wild-type HSC-induced MDSCs expressed lower levels of CD40, CD86, and MHC II, and a higher level of B7-H1 surface molecules, as well as increased the production of iNOS and arginase I compared with MDSCs induced by IL-6-deficient HSCs in vitro. A murine-transplanted model of the liver tumor showed that HCCs cotransplanted with HSCs could significantly enhance the tumor area and detect more MDSCs compared with HCCs alone or HCCs cotransplanted with HSCs lacking IL-6. In conclusion, the results indicated that MDSCs are induced mainly by HSCs through IL-6 signaling and produce inhibitory enzymes to reduce T-cell immunity and then promote HCC progression within the tumor microenvironment. Therapies targeting the pathway involved in MDSC production or its immune-modulating pathways can serve as an alternative immunotherapy for HCC.

705 Anti-tumor activity of CB-668, a potent, selective and orally bioavailable small-molecule inhibitor of the immuno-suppressive enzyme Interleukin 4 (IL-4)-Induced Gene 1 (IL4I1)

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A747-A747
Author(s):  
Andrew MacKinnon ◽  
Deepthi Bhupathi ◽  
Jason Chen ◽  
Tony Huang ◽  
Weiqun Li ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Tumor Microenvironment ◽  
Immune Cell ◽  
Interleukin 4 ◽  
Mouse Tumor ◽  
Syngeneic Mouse ◽  
Molecule Inhibitor ◽  
Anti Tumor Activity ◽  
Mouse Tumor Models

BackgroundTumors evade destruction by the immune system through multiple mechanisms including altering metabolism in the tumor microenvironment. Metabolic control of immune responses occurs through depletion of essential nutrients or accumulation of toxic metabolites that impair immune cell function and promote tumor growth. The secreted enzyme interleukin 4 (IL-4)-induced gene 1 (IL4I1) is an L-phenylalanine oxidase that catabolizes phenylalanine and produces phenyl-pyruvate and hydrogen peroxide. IL4I1 regulates several aspects of adaptive immunity in mice, including inhibition of cytotoxic T cells through its production of hydrogen peroxide (reviewed in1). In human tumors, IL4I1 expression is significantly elevated relative to normal tissues and is notably high in ovarian tumors and B cell lymphomas. Motivated by the hypothesis that IL4I1 is an immuno-metabolic enzyme that suppresses anti-tumor immunity, we discovered CB-668, the first known small-molecule inhibitor of IL4I1.MethodsIL4I1 enzymatic activity was measured using an HRP-coupled enzyme assay. RNA in-situ hybridization was carried out on the RNAScope platform. Syngeneic mouse tumor models were used to evaluate the anti-tumor activity of CB-668. The level of phenyl-pyruvate in tumor homogenates was measured by LC/MS.ResultsOur clinical candidate, CB-668 is a potent and selective non-competitive inhibitor of IL4I1 (IC50 = 15 nM). CB-668 has favorable in vitro ADME properties and showed low clearance and high oral bioavailability in rodents. Twice-daily oral administration of CB-668 was well-tolerated in mice and resulted in single-agent anti-tumor activity in the syngeneic mouse tumor models B16-F10, A20, and EG7. Oral CB-668 administration reduced the levels of phenyl-pyruvate in the tumor, consistent with inhibition of IL4I1 enzymatic activity. Anti-tumor activity of CB-668 was immune cell-mediated since efficacy was abrogated in CD8-depleted mice, and CB-668 treatment caused increased expression of pro-inflammatory immune genes in the tumor. Moreover, CB-668 had no direct anti-proliferative activity on tumor cells grown in vitro (IC50 > 50 µM). CB-668 also favorably combined with anti-PD-L1 therapy to reduce tumor growth in the B16-F10 tumor model.ConclusionsThese data support an immune-mediated anti-tumor effect of IL4I1 inhibition by CB-668, and suggest inhibition of IL4I1 represents a novel strategy for cancer immuno-therapy.ReferencesMolinier-Frenkel V, Prévost-Blondel A, and Castellano F. The IL4I1 Enzyme: A New Player in the Immunosuppressive Tumor Microenvironment. Cells 2019;8:1–9.

scholarly journals 843 Development and engineering of human sialidase for degradation of immunosuppressive sialoglycans to treat cancer

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A884-A884
Author(s):  
Li Peng ◽  
Lizhi Cao ◽  
Sujata Nerle ◽  
Robert LeBlanc ◽  
Abhishek Das ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Cells ◽  
First Generation ◽  
Single Agent ◽  
Mouse Tumor ◽  
Cytokine Release ◽  
Tumor Models ◽  
Cell Immunity ◽  
Mouse Tumor Models

BackgroundSialoglycans, a type of glycans with a terminal sialic acid, have emerged as a critical glyco-immune checkpoint that impairs antitumor response by inhibiting innate and adaptive immunity. Upregulation of sialoglycans on tumors has been observed for decades and correlates with poor clinical outcomes across many tumor types. We previously showed that targeted desialylation of tumors using a bifunctional sialidase x antibody molecule, consisting of sialidase and a tumor-associated antigen (TAA)-targeting antibody, has led to robust single-agent efficacy in mouse tumor models. In addition to tumor cells, most immune cells present substantially more abundant sialoglycans than non-hematological healthy cells, which may also contribute to immunosuppression. Therefore, we studied the impact of immune cell desialylation and evaluated the therapeutic potential of a newly developed sialidase-Fc fusion (Bi-Sialidase), which lacks a TAA-targeting moiety and consists of engineered human neuraminidase 2 (Neu2) and human IgG1 Fc region, in preclinical mouse tumor models.MethodsThe first generation Neu2 variant was further optimized to improve titers and stability to constructed Bi-Sialidase. Bi-Sialidase’s desialylation potency and impact on immune responses were studied in vitro using various human immune functional assays, including T-cell activation, allogeneic mixed lymphocyte reaction, antibody-dependent cellular cytotoxicity, macrophages polarization/activation, neutrophil activation, and peripheral blood mononuclear cell (PBMC) cytokine release assays. We evaluated its antitumor efficacy in mouse tumor models. Bi-Sialidase’s safety profile was characterized by conducting rat and non-human primate (NHP) toxicology studies.ResultsThe optimized Bi-Sialidase achieved a titer of 2.5 g/L from a 15-day fed-batch Chinese hamster ovary cell culture; in contrast, the wild-type and first-generation Neu2 had no production or a low titer (<0.1 g/L) under similar conditions, respectively. We demonstrated that Bi-Sialidase led to dose-dependent desialylation of immune cells and potentiated T-cell immunity, without impacting NK, macrophage, or neutrophil activation by desialylating immune cells. Activated and exhausted T cells upregulated surface sialoglycans and Bi-Sialidase-mediated desialylation reinvigorated exhausted-like T cells as measured by IFNg production. Bi-Sialidase treatment also enhanced DC priming and activation of naïve T cells by desialylating both T cells and DCs. Furthermore, Bi-Sialidase showed single-agent antitumor activity in multiple mouse tumor models, including MC38, CT26, A20, and B16F10. Importantly, Bi-Sialidase did not cause cytokine release in human PBMC assays and was tolerated to up to 100 mg/kg in rats and NHPs, demonstrating a wide safety margin.ConclusionsBi-Sialidase with an optimized Neu2 offers a novel immunomodulatory approach to enhancing T-cell immunity by desialylating immunosuppressive sialoglycans for cancer treatment.

scholarly journals CD40L+ CD4+ memory T cells migrate in a CD62P-dependent fashion into reactive lymph nodes and license dendritic cells for T cell priming

2008 ◽  
Vol 205 (11) ◽  
pp. 2561-2574 ◽  
Author(s):  
Alfonso Martín-Fontecha ◽  
Dirk Baumjohann ◽  
Greta Guarda ◽  
Andrea Reboldi ◽  
Miroslav Hons ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Lymph Nodes ◽  
Memory T Cells ◽  
Effector Memory ◽  
High Endothelial Venules ◽  
T Cell Priming ◽  
Dc Maturation

There is growing evidence that the maturation state of dendritic cells (DCs) is a critical parameter determining the balance between tolerance and immunity. We report that mouse CD4+ effector memory T (TEM) cells, but not naive or central memory T cells, constitutively expressed CD40L at levels sufficient to induce DC maturation in vitro and in vivo in the absence of antigenic stimulation. CD4+ TEM cells were excluded from resting lymph nodes but migrated in a CD62P-dependent fashion into reactive lymph nodes that were induced to express CD62P, in a transient or sustained fashion, on high endothelial venules. Trafficking of CD4+ TEM cells into chronic reactive lymph nodes maintained resident DCs in a mature state and promoted naive T cell responses and experimental autoimmune encephalomyelitis (EAE) to antigens administered in the absence of adjuvants. Antibodies to CD62P, which blocked CD4+ TEM cell migration into reactive lymph nodes, inhibited DC maturation, T cell priming, and induction of EAE. These results show that TEM cells can behave as endogenous adjuvants and suggest a mechanistic link between lymphocyte traffic in lymph nodes and induction of autoimmunity.

scholarly journals SOD3 induces a HIF-2α-dependent program in endothelial cells that provides a selective signal for tumor infiltration by T cells

2020 ◽  
Vol 8 (1) ◽  
pp. e000432 ◽  
Author(s):  
Lorena Carmona-Rodríguez ◽  
Diego Martínez-Rey ◽  
Maria Jesús Fernández-Aceñero ◽  
Alicia González-Martín ◽  
Mateo Paz-Cabezas ◽  
...  
Keyword(s):  
T Cells ◽  
Endothelial Cells ◽  
T Cell ◽  
Tumor Microenvironment ◽  
T Lymphocytes ◽  
Adhesion Molecule ◽  
Cell Infiltration ◽  
Tumor Infiltration ◽  
T Cell Infiltration

BackgroundTumor-infiltrating lymphocytes (TILs), mainly CD8+ cytotoxic T lymphocytes (CTL), are linked to immune-mediated control of human cancers and response to immunotherapy. Tumors have nonetheless developed specific mechanisms that selectively restrict T cell entry into the tumor microenvironment. The extracellular superoxide dismutase (SOD3) is an anti-oxidant enzyme usually downregulated in tumors. We hypothesize that upregulation of SOD3 in the tumor microenvironment might be a mechanism to boost T cell infiltration by normalizing the tumor-associated endothelium.ResultsHere we show that SOD3 overexpression in endothelial cells increased in vitro transmigration of naïve and activated CD4+ and CD8+ T cells, but not of myeloid cells. Perivascular expression of SOD3 also specifically increased CD4+ and CD8+ effector T cell infiltration into tumors and improved the effectiveness of adoptively transferred tumor-specific CD8+ T cells. SOD3-induced enhanced transmigration in vitro and tumor infiltration in vivo were not associated to upregulation of T cell chemokines such as CXCL9 or CXCL10, nor to changes in the levels of endothelial adhesion receptors such as intercellular adhesion molecule-1 (ICAM-1) or vascular cell adhesion molecule-1 (VCAM-1). Instead, SOD3 enhanced T cell infiltration via HIF-2α-dependent induction of specific WNT ligands in endothelial cells; this led to WNT signaling pathway activation in the endothelium, FOXM1 stabilization, and transcriptional induction of laminin-α4 (LAMA4), an endothelial basement membrane component permissive for T cell infiltration. In patients with stage II colorectal cancer, SOD3 was associated with increased CD8+ TIL density and disease-free survival. SOD3 expression was also linked to a T cell–inflamed gene signature using the COAD cohort from The Cancer Genome Atlas program.ConclusionOur findings suggest that SOD3-induced upregulation of LAMA4 in endothelial cells boosts selective tumor infiltration by T lymphocytes, thus transforming immunologically “cold” into “hot” tumors. High SOD3 levels are associated with human colon cancer infiltration by CD8+ T cells, with potential consequences for the clinical outcome of these patients. Our results also uncover a cell type–specific, distinct activity of the WNT pathway for the regulation of T cell infiltration into tumors.

scholarly journals Targeted in-vitro-stimulation reveals highly proliferative multi-virus-specific human central memory T cells as candidates for prophylactic T cell therapy

PLoS ONE ◽  
2019 ◽  
Vol 14 (9) ◽  
pp. e0223258 ◽  
Author(s):  
Benjamin Faist ◽  
Fabian Schlott ◽  
Christian Stemberger ◽  
Kevin M. Dennehy ◽  
Angela Krackhardt ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Therapy ◽  
Memory T Cells ◽  
Central Memory ◽  
T Cell Therapy ◽  
Central Memory T Cells

Overcoming the breast tumor microenvironment by targeting MDSCs through CAR-T cell therapy.

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. 1032-1032
Author(s):  
Saisha Abhay Nalawade ◽  
Paul Shafer ◽  
Pradip Bajgain ◽  
Katie McKenna ◽  
Arushana Ali ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
T Cells ◽  
T Cell ◽  
Tumor Microenvironment ◽  
Nuclear Translocation ◽  
T Cell Proliferation ◽  
Tumor Site ◽  
Car T Cells ◽  
Car T

1032 Background: Successful targeting of solid tumors such as breast cancer (BC) using CAR T cells (CARTs) has proven challenging, largely due to the immune suppressive tumor microenvironment (TME). Myeloid derived suppressor cells (MDSCs) inhibit CART’s function and persistence within the breast TME. We generated CAR T cells targeting tumor-expressed mucin 1 (MUC1) (Bajgain P et al, 2018) for BC. To potentiate expansion and persistence of MUC1 CARTs and modulate the suppressive TME, we developed a novel chimeric co-stimulatory receptor, TR2.4-1BB, encoding a ScFv derived from a TNF-related apoptosis-inducing ligand receptor 2 (TR2) mAb followed by a 4-1BB endodomain. We hypothesize that engagement with TR2 expressed on TME-resident MDSCs, will lead to both MDSC apoptosis and CART co-stimulation, promoting T cell persistence and expansion at tumor site. Methods: Function of the novel TR2.4-1BB receptor, was assessed by exposing non-transduced (NT) and TR2.4-1BB transduced T cells to recombinant TR2 and nuclear translocation of NFκB was measured by ELISA. Functionality of in vitro generated MDSCs was determined by the suppression assay. In vitro CART/costimulatory receptor T cell function was measured by cytotoxicity assays using MUC1+ tumor targets in presence or absence of MDSCs. In vivo anti-tumor activity was assessed using MDSC enriched tumor-bearing mice using calipers to assess tumor volume and bioluminescence imaging to track T cells. Results: Nuclear translocation of NFκB was detected only in TR2.4-1BB T cells. MDSCs significantly attenuated T cell proliferation by 50±5% and IFNγ production by half compared with T cells cultured alone. Additionally, presence of MDSCs, diminished cytotoxic potential of MUC1 CARTs against MUC1+ BC cell lines by 25%. However, TR2.4-1BB expression on CAR.MUC1 T cells induced MDSC apoptosis thereby restoring the cytotoxic activity of CAR.MUC1 against MUC1+ BC lines in presence of TR2.4-1BB (67±8.5%). There was an approximate two-fold increase in tumor growth due enhanced angiogenesis and fibroblast accumulation in mice receiving tumors + MDSCs compared to tumors alone. Treatment of these MDSC-enriched tumors with MUC1.TR2.4-1BB CARTs led to superior tumor cell killing and significant reduction in tumor growth (24.54±8.55 mm3) compared to CAR.MUC1 (469.79.9±81.46mm3) or TR2.4-1BB (434.86±64.25 mm3) T cells alone (Day 28 after T cell injection). The treatment also improved T cell proliferation and persistence at the tumor site. Thereby, leading to negligible metastasis demonstrating ability of CARTs to eliminate tumor and prevent dissemination. We observed similar results using HER2.TR2.4-1BB CARTs in a HER2+ BC model. Conclusions: Our findings demonstrate that CARTs co-expressing our novel TR2.4-1BB receptor have higher anti-tumor potential against BC tumors and infiltrating MDSCs, resulting in TME remodeling and improved T cell proliferation at the tumor site.

Bone Marrow Myeloid-Derived Suppressor Cells (MDSC) Inhibit Graft Versus Host Disease (GVHD) Via An Arginase-1 Dependant Mechanism That Is Upregulated by IL-13

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 241-241
Author(s):  
Steven L Highfill ◽  
Paulo Rodriguez ◽  
Qing Zhou ◽  
Christine A Goetz ◽  
Rachelle Veenstra ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
State University ◽  
Medical College ◽  
Louisiana State University ◽  
Arginase 1 ◽  
University Patents ◽  
Donor T Cells

Abstract Abstract 241 Background: Myeloid-derived suppressor cells (MDSC) are a well-defined population of cells that accumulate in the tissue of tumor-bearing animals and are known to inhibit immune responses. Here, we have developed a novel method by which we can generate MDSC from the BM of wild type mice. Our goals were to determine the effectiveness of these cells in inhibiting an allogeneic T-cell reaction, the mechanism by which this occurs, and the impact on the graft-versus-tumor (GVT) activity of donor T-cells. Results: Our results show that the incubation of WT BM with G-CSF and GM-CSF for a period of 4 days results in a population of cells predominately co-expressing CD11b and Gr1 (50%). Most of these cells have a monocytic phenotype of Ly6GloLy6C+ (73%) and also express other markers associated with MDSCs such as IL4Ra (64%), F4/80 (63%) and CD115 (43%). Such MDSC potently inhibited in vitro allogeneic T-cell responses and the addition of IL-13 to the MDSC culture enhanced their suppressive capacity (60% suppression by MDSC at the peak of the response, day 5 vs. 75% suppression by MDSC-IL13, P<0.001). Suppression was dependent on L-arginine depletion because only the addition excess L-arginine, but not tryptophan, resulted in a significant reduction in suppression (60% reduction at day 4, P=0.001). Adding IL-13 to the MDSC cultures resulted in arginase-1 upregulation (20 fold increase in expression over control BM for MDSC vs. 350 fold increase in MDSC-IL13, P<0.001). The arginase inhibitor, nor-NOHA, significantly reduced MDSC suppression in vitro. GNC2 kinase knockout T cells were resistant to suppression, consistent with their inability to sense L-arginine depletion. Although iNOS was upregulated 5-fold in MDSCs vs BM, IL13 addition did not further upregulate iNOS. Suppression was mostly contact-independent. In vivo, MDSC-IL13 derived from GFP transgenic BM migrated to sites of allopriming. MDSC-IL13 from luciferase transgenic donors increased over a 3 week period of time as assessed by bioluminescent imaging. Although both MDSC and MDSC-IL13 inhibited GVHD lethality, MDSC-IL13 were more effective at enhancing survival (MDSC vs. MDSC-IL13, P=0.001). When compared with untreated mice, GVHD inhibition in MDSC-IL13 treated mice was associated with: 1) Limited donor T-cell proliferation (CD4+CFSE−, 40% vs. 17%, P=0.01; CD8+CFSE−, 51% vs. 16%, P=0.01); 2) Decreased donor T-cell activation (CD4+CD62L−, 74% vs. 50%, P<0.001; CD8+CD62L−, 77% vs. 41%, P<0.001); 3) Decreased proinflammatory cytokine production (CD4+IFNg+, 37% vs. 24%, P=0.04; CD8+IFNg+, 30% vs. 15%, P=0.007); 4) Decreased expression of intracellular CD3z chain (CD4+CD3z+, 86% vs. 56%, P<0.001; CD8+CD3z+, 85% vs. 68%, P<0.001). On day 14, donor MDSC-IL13 cells, distinguishable from donor BM and the host by a CD45 congenic marker, were re-isolated from the spleen of murine GVHD recipients. MDSC-IL13 cells retained their initial phenotype and were potent ex vivo suppressors of an allogeneic T cell response. Arginase-1 knockout MDSC-IL13 did not have a significant effect on reducing GVHD, indicating that arginase-1 expression was vital to the in vivo suppressive effect of MDSCs. MDSC-IL13 did not abrogate the graft-versus-tumor effect of donor T-cells. In MDSC-IL13 treated mice, donor T-cells retained their ability to eliminate A20 lymphoma cells, and at the same time, had improved survival when compared to mice receiving A20 cells plus T-cells all of which succumbed to GVHD (BM+T+A20 vs. BM+T+A20+MDSC-IL13, P<0.001). Since arginase-1 expression was critical for suppression, we exploited this mechanism of action by administering a pegylated form of human arginase-1 (PEG-arg1) to systemically deplete L-arginine. We find that GVHD survival is significantly improved (BM+T vs. BM+T+PEG-arg1, P=0.003). Conclusions: We can conclude that BM-derived MDSC-IL13 have the ability to dampen GVHD and enhance survival when using a fully-mismatched murine model of BMT. Arginase-1 expression was found to play a critical role in MDSC-mediated suppression. A GVT effect was not ablated by MDSC-IL13. In vivo administration of PEG-arg1 resulted in L-arginine depletion and significant GVHD reduction. Both MDSC infusion and PEG-arg1 administration are promising strategies that warrant further preclinical studies to prevent GVHD that may be readily translatable in the clinic. Disclosures: Highfill: UIniversity of Minnesota: Patents & Royalties; Louisiana State University: Patents & Royalties; Medical College of Georgia: Patents & Royalties. Rodriguez:University of Minnesota: Patents & Royalties; Louisiana State University: Patents & Royalties; Medical College of Georgia: Patents & Royalties. Ochoa:University of Minnesota: Patents & Royalties; Louisiana State University: Patents & Royalties; Medical College of Georgia: Patents & Royalties. Blazar:University of Minnesota: Patents & Royalties; Louisiana State University: Patents & Royalties; Medical College of Georgia: Patents & Royalties.

Naïve T Cell-Derived CTL Recognize Atypical Epitopes of CMVpp65 with Higher Avidity Than CMV-Seropositive Donor-Derived CTL – a Basis for Treatment of Post-Transplant Viral Infection by Adoptive Transfer of T Cells From Virus-naïve Donors

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3002-3002
Author(s):  
Patrick J Hanley ◽  
J. Joseph Melenhorst ◽  
Phillip Scheinberg ◽  
Gail J Demmler-Harrison ◽  
Daniele Lilleri ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Adoptive Transfer ◽  
Memory T Cells ◽  
Conflicts Of Interest ◽  
Target Cells ◽  
Naive T Cells ◽  
Naïve T Cells ◽  
Infected Cells

Abstract Abstract 3002 Adoptive transfer of CMV-specific T cells derived from adult CMV-seropositive (CMVpos) donors can effectively restore antiviral immunity after stem cell transplantation. However due to the absence of CMV antigen-specific memory T cells in cord blood (CB) and adult CMV-seronegative (CMVneg) donors, different culture systems are required to generate virus-specific T cells for adoptive transfer. With a novel protocol we have generated CMVpp65-specific T cells from CB and found that 15/15 CB T cell lines recognized atypical epitopes of pp65. We then explored the generation of CMV-specific CTL from CMVneg donors using a GMP-compliant methodology and studied the epitopes recognized. CD45RA+ naive T cells were selected from the peripheral blood of CMVneg donors and stimulated with pp65-Pepmix-pulsed dendritic cells with supplemented with IL-7, IL-12, and IL-15. For subsequent stimulations T cells were stimulated with pp65-Pepmix-pulsed EBV-LCL and IL-15 or IL-2. CMVpp65-specific T cells (CMV-CTL) expanded from 8 of 11 CMVneg donors were primarily CD8+ T cells (mean 71%). Naïve donor CMV-CTL secreted IFN- γ in response to pp65 peptides (mean 224; range: 38–611 SFC/1×105 cells) compared to irrelevant peptides (mean 12;Range 3–37) as measured in Elispot assays and lysed pp65-pulsed target cells (mean :48; range :15–70%) but not negative controls (mean 22; range 4–40%). These CMV-CTL derived from naive (but not memory) T cells recognized only novel and atypical pp65 epitopes (such as the HLA-A2-restricted epitopes LQTGIHVRV and MLNIPSINV) but not the typical HLA-A2-restricted epitope NLVPMVATV as confirmed by ELISPOT and multimer analysis. These results are similar to CB-derived CTL. Analysis of the avidity of naïve donor CTL specific for the atypical CMV epitopes revealed that the 1/2 maximum effective concentration was similar (mean: 600 pM) to CMVpos CTL recognizing typical epitopes (mean: 300 pM), and more avid than CMVpos CTL recognizing atypical epitopes (mean: 4 nM), highlighting the difference between naïve-derived and memory-derived CTL. TCR sequencing performed on T cells specific for typical (CMVpos) and atypical (CMVpos, CMVneg, and CB) epitopes revealed that CMVpos donor CMV-CTL recognizing typical epitopes were markedly more oligoclonal than CTL recognizing the atypical epitopes derived from CB, CMVpos, or CMVneg donors. To address the concern that atypical epitopes might not be naturally presented by CMV-infected cells and therefore not recognized by in vitro generated CTL, we tested whether CMV CTL (from CB, CMVpos, CMVneg) generated using CMV AD169-infected fibroblasts or CMV VR1814-infected DCs would recognize the same epitopes. As before, CMVpos CMV CTL recognized typical epitopes of pp65 while CB and CMVneg CMV CTL recognized only atypical epitopes, suggesting that the epitopes are naturally processed and presented by APCs, and that the atypical epitopes observed are not an artifact of using exogenous antigens like the pp65 Pepmix. Thus, despite their unusual repertoire, T cells derived from CB or CMVneg donors are likely to control CMV infection. These results reveal major differences in the naïve and memory CMV specific T cell repertoire that merits further exploration. Nevertheless, we demonstrated that atypical epitopes are naturally presented by CMV infected cells and we are now evaluating the clinical efficacy of these CTL in recipients of CBT. These studies should determine if naive T cells primed in vitro are able to persist and establish memory and virus protection in vivo. Disclosures: No relevant conflicts of interest to declare.

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