scholarly journals Tumor-induced MDSC act via remote control to inhibit L-selectin-dependent adaptive immunity in lymph nodes

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Amy W Ku ◽  
Jason B Muhitch ◽  
Colin A Powers ◽  
Michael Diehl ◽  
Minhyung Kim ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Adaptive Immunity ◽  
Suppressor Cells ◽  
Cell Trafficking ◽  
Myeloid Derived Suppressor Cells ◽  
T Cell Trafficking ◽  
Tumor Bearing ◽  
Cancer Immunity ◽  
Prevailing View

Myeloid-derived suppressor cells (MDSC) contribute to an immunosuppressive network that drives cancer escape by disabling T cell adaptive immunity. The prevailing view is that MDSC-mediated immunosuppression is restricted to tissues where MDSC co-mingle with T cells. Here we show that splenic or, unexpectedly, blood-borne MDSC execute far-reaching immune suppression by reducing expression of the L-selectin lymph node (LN) homing receptor on naïve T and B cells. MDSC-induced L-selectin loss occurs through a contact-dependent, post-transcriptional mechanism that is independent of the major L-selectin sheddase, ADAM17, but results in significant elevation of circulating L-selectin in tumor-bearing mice. Even moderate deficits in L-selectin expression disrupt T cell trafficking to distant LN. Furthermore, T cells preconditioned by MDSC have diminished responses to subsequent antigen exposure, which in conjunction with reduced trafficking, severely restricts antigen-driven expansion in widely-dispersed LN. These results establish novel mechanisms for MDSC-mediated immunosuppression that have unanticipated implications for systemic cancer immunity.

scholarly journals Myeloid-derived suppressor cells are bound and inhibited by anti-thymocyte globulin

2019 ◽  
Vol 25 (1) ◽  
pp. 46-59 ◽  
Author(s):  
Young Suk Lee ◽  
Eduardo Davila ◽  
Tianshu Zhang ◽  
Hugh P Milmoe ◽  
Stefanie N Vogel ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
T Cells ◽  
T Cell ◽  
Suppressor Cells ◽  
Arginase Activity ◽  
T Cell Proliferation ◽  
Myeloid Derived Suppressor Cells ◽  
Tumor Bearing ◽  
And Function

Myeloid-derived suppressor cells (MDSCs) inhibit T cell responses and are relevant to cancer, autoimmunity and transplant biology. Anti-thymocyte globulin (ATG) is a commonly used T cell depletion agent, yet the effect of ATG on MDSCs has not been investigated. MDSCs were generated in Lewis Lung Carcinoma 1 tumor-bearing mice. MDSC development and function were assessed in vivo and in vitro with and without ATG administration. T cell suppression assays, RT-PCR, flow cytometry and arginase activity assays were used to assess MDSC phenotype and function. MDSCs increased dramatically in tumor-bearing mice and the majority of splenic MDSCs were of the polymorphonuclear subset. MDSCs potently suppressed T cell proliferation. ATG-treated mice developed 50% fewer MDSCs and these MDSCs were significantly less suppressive of T cell proliferation. In vitro, ATG directly bound 99.6% of MDSCs. CCR7, L-selectin and LFA-1 were expressed by both T cells and MDSCs, and binding of LFA-1 was inhibited by ATG pre-treatment. Arg-1 and PD-L1 transcript expression were reduced 30–40% and arginase activity decreased in ATG-pretreated MDSCs. MDSCs were bound and functionally inhibited by ATG. T cells and MDSCs expressed common Ags which were also targets of ATG. ATG may be helpful in tumor models seeking to suppress MDSCs. Alternatively, ATG may inadvertently inhibit important T cell regulatory events in autoimmunity and transplantation.

501 VISTA regulates the differentiation and suppressive function of myeloid-derived suppressor cells

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A536-A536
Author(s):  
Juan Dong ◽  
Cassandra Gilmore ◽  
Hieu Ta ◽  
Keman Zhang ◽  
Sarah Stone ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Signaling Pathways ◽  
Immune Checkpoint ◽  
Suppressor Cells ◽  
Myeloid Cell ◽  
Myeloid Derived Suppressor Cells ◽  
Checkpoint Protein ◽  
Suppressive Function

BackgroundV-domain immunoglobulin suppressor of T cell activation (VISTA) is a B7 family inhibitory immune checkpoint protein and is highly expressed on myeloid cells and T cells.1 VISTA acts as both an inhibitory ligand when expressed on antigen-presenting cells and a receptor when expressed on T cells. Our recent study has shown that VISTA is a myeloid cell-specific immune checkpoint and that blocking VISTA can reprogram suppressive myeloid cells and promote a T cell-stimulatory tumor microenvironment.2 In this study, we further demonstrate that VISTA blockade directly alters the differentiation and the suppressive function of myeloid-derived suppressor cells (MDSC).MethodsFlow cytometry was performed to examine VISTA expression on MDSCs in multiple murine tumor models including the B16BL6 melanoma model, MC38 colon cancer model, and the KPC pancreatic cancer models. To examine the role of VISTA in controlling the differentiation and suppressive function of MDSCs, we cultured wild type (WT) and VISTA.KO bone marrow progenitor cells with GM-CSF and IL-6 to induce BM -derived MDSCs.ResultsOur preliminary results show that VISTA is highly expressed on M-MDSCs in B16BL6, MC38 and KPC tumors. In BM-derived MDSCs, VISTA deletion significantly altered the signaling pathways and the differentiation of MDSCs. Multiple inflammatory signaling pathways were downregulated in VISTA KO MDSCs, resulting in decreased production of cytokines such as IL1 and chemokines such as CCL2/4/9, as well as significantly impaired their ability to suppress the activation of CD8+ T cells. The loss of suppressive function in VISTA KO MDSCs is correlated with significantly reduced expression of iNOS. To validate the results from BM-MDSCs, we sorted CD11b+CD11c-Ly6C+Ly6G- M-MDSCs and CD11b+CD11c-Ly6G+ G-MDSCs from B16BL6 tumor tissues and tested the ability of a VISTA-blocking mAb to reverse the suppressive effects of tumor-derived MDSCs. Our results show that blocking VISTA impaired the suppressive function of tumor-derived M-MDSC but not G-MDSCs.ConclusionsTaken together, these results demonstrate a crucial role of VISTA in regulating the differentiation and function of MDSCs, and that blocking VISTA abolishes MDSC-mediated T cell suppression, thereby boosting.Ethics ApprovalAll in vivo studies were reviewed and approved by Institutional Animal Care and Use Committee (Approval number 2019-2142).ReferencesXu W, Hire T, Malarkannan, S. et al. The structure, expression, and multifaceted role of immune-checkpoint protein VISTA as a critical regulator of anti-tumor immunity, autoimmunity, and inflammation. Cell Mol Immunol 2018;15:438–446.Xu W, Dong J, Zheng Y, et al. Immune-checkpoint protein VISTA regulates antitumor immunity by controlling myeloid cell-mediated inflammation and immunosuppression. Cancer Immunol Res 2019;7:1497–510.

The Rac activator Tiam1 controls efficient T-cell trafficking and route of transendothelial migration

Blood ◽  
2009 ◽  
Vol 113 (24) ◽  
pp. 6138-6147 ◽  
Author(s):  
Audrey Gérard ◽  
Rob A. van der Kammen ◽  
Hans Janssen ◽  
Saskia I. Ellenbroek ◽  
John G. Collard
Keyword(s):  
T Cells ◽  
Endothelial Cells ◽  
T Cell ◽  
Transendothelial Migration ◽  
Contact Hypersensitivity ◽  
Cell Trafficking ◽  
T Cell Trafficking ◽  
Cell Arrest

Abstract Migration toward chemoattractants is a hallmark of T-cell trafficking and is essential to produce an efficient immune response. Here, we have analyzed the function of the Rac activator Tiam1 in the control of T-cell trafficking and transendothelial migration. We found that Tiam1 is required for chemokine- and S1P-induced Rac activation and subsequent cell migration. As a result, Tiam1-deficient T cells show reduced chemotaxis in vitro, and impaired homing, egress, and contact hypersensitivity in vivo. Analysis of the T-cell transendothelial migration cascade revealed that PKCζ/Tiam1/Rac signaling is dispensable for T-cell arrest but is essential for the stabilization of polarization and efficient crawling of T cells on endothelial cells. T cells that lack Tiam1 predominantly transmigrate through individual endothelial cells (transcellular migration) rather than at endothelial junctions (paracellular migration), suggesting that T cells are able to change their route of transendothelial migration according to their polarization status and crawling capacity.

scholarly journals Myeloid-Derived Suppressor Cells Mediate T Cell Dysfunction in Nonhuman Primate TB Granulomas

mBio ◽  
2021 ◽  
Author(s):  
Bindu Singh ◽  
Dhiraj K. Singh ◽  
Shashank R. Ganatra ◽  
Ruby A. Escobedo ◽  
Shabaana Khader ◽  
...  
Keyword(s):  
T Cell ◽  
Adaptive Immunity ◽  
Nonhuman Primate ◽  
Immune Surveillance ◽  
Suppressor Cells ◽  
Myeloid Derived Suppressor Cells ◽  
Cell Dysfunction ◽  
First Response ◽  
T Cell Stimulation ◽  
T Cell Dysfunction

Myeloid cells are immunocytes of innate origin that orchestrate the first response toward pathogens via immune surveillance (uptake and killing), antigen presentation, and initiation of adaptive immunity by T cell stimulation. However, MDSCs are a subset of innate immunocytes that deviate to an immunoregulatory phenotype.

scholarly journals Expansion of Functional Myeloid-Derived Suppressor Cells in Controlled Human Malaria Infection

2021 ◽  
Vol 12 ◽  
Author(s):  
Carlos Lamsfus Calle ◽  
Rolf Fendel ◽  
Anurag Singh ◽  
Thomas L. Richie ◽  
Stephen L. Hoffman ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
Malaria Infection ◽  
Malaria Vaccine ◽  
Suppressor Cells ◽  
T Cell Proliferation ◽  
Myeloid Derived Suppressor Cells ◽  
Controlled Human Malaria Infection

Malaria can cause life-threatening complications which are often associated with inflammatory reactions. More subtle, but also contributing to the burden of disease are chronic, often subclinical infections, which result in conditions like anemia and immunologic hyporesponsiveness. Although very frequent, such infections are difficult to study in endemic regions because of interaction with concurrent infections and immune responses. In particular, knowledge about mechanisms of malaria-induced immunosuppression is scarce. We measured circulating immune cells by cytometry in healthy, malaria-naïve, adult volunteers undergoing controlled human malaria infection (CHMI) with a focus on potentially immunosuppressive cells. Infectious Plasmodium falciparum (Pf) sporozoites (SPZ) (PfSPZ Challenge) were inoculated during two independent studies to assess malaria vaccine efficacy. Volunteers were followed daily until parasites were detected in the circulation by RT-qPCR. This allowed us to analyze immune responses during pre-patency and at very low parasite densities in malaria-naïve healthy adults. We observed a consistent increase in circulating polymorphonuclear myeloid-derived suppressor cells (PMN-MDSC) in volunteers who developed P. falciparum blood stage parasitemia. The increase was independent of preceding vaccination with a pre-erythrocytic malaria vaccine. PMN-MDSC were functional, they suppressed CD4+ and CD8+ T cell proliferation as shown by ex-vivo co-cultivation with stimulated T cells. PMN-MDSC reduced T cell proliferation upon stimulation by about 50%. Interestingly, high circulating PMN-MDSC numbers were associated with lymphocytopenia. The number of circulating regulatory T cells (Treg) and monocytic MDSC (M-MDSC) showed no significant parasitemia-dependent variation. These results highlight PMN-MDSC in the peripheral circulation as an early indicator of infection during malaria. They suppress CD4+ and CD8+ T cell proliferation in vitro. Their contribution to immunosuppression in vivo in subclinical and uncomplicated malaria will be the subject of further research. Pre-emptive antimalarial pre-treatment of vaccinees to reverse malaria-associated PMN-MDSC immunosuppression could improve vaccine response in exposed individuals.

scholarly journals The race for the prize: T-cell trafficking strategies for optimal surveillance

Blood ◽  
2012 ◽  
Vol 120 (7) ◽  
pp. 1432-1438 ◽  
Author(s):  
Minyi Lee ◽  
Judith N. Mandl ◽  
Ronald N. Germain ◽  
Andrew J. Yates
Keyword(s):  
T Cells ◽  
Lymph Node ◽  
T Cell ◽  
Optimization Problem ◽  
Cell Trafficking ◽  
T Cell Trafficking ◽  
Cell Responses ◽  
Major Histocompatibility Complexes ◽  
Draining Lymph Node ◽  
Slow Transit

Abstract The initiation of T-cell responses requires rare precursors to locate a draining lymph node (dLN) and encounter dendritic cells (DCs) presenting peptide-major histocompatibility complexes (pMHCs). To locate this needle in the haystack rapidly, T cells face an optimization problem—what is the most efficient trafficking strategy for surveillance and recirculation through blood? Two extremes are scanning low numbers of DCs per node with frequent recirculation, or meticulous surveillance with infrequent recirculation. Naive T cells also require stimulation by self-pMHCs. To enable efficient location of both foreign and self, has evolution settled on an optimum time for T cells to spend surveying each lymph node? Using a data-driven mathematical model, we show the most efficient strategy for detecting antigen in a dLN depends on its abundance. Detection of low-density antigen is optimized with systemically slow transit. In contrast, at high densities or if dLN egress is restricted, rapid transit through other nodes is optimal. We argue that blood-lymph recirculation dynamics facilitate a trade-off, and are consistent with dominant roles for the very early detection of rare foreign antigens in a dLN, and the efficient accumulation of signals from systemically distributed self-antigens.

A killer sidekick for antitumor T cells

2019 ◽  
Vol 11 (479) ◽  
pp. eaaw5325
Author(s):  
Christian S. Hinrichs
Keyword(s):  
T Cells ◽  
T Cell ◽  
Nk Cells ◽  
Suppressor Cells ◽  
Myeloid Derived Suppressor Cells ◽  
Car T Cell ◽  
Car T

Engineered NK cells kill myeloid-derived suppressor cells to aid CAR-T cell antitumor responses.

scholarly journals Expansion of myeloid-derived suppressor cells in patients with severe coronavirus disease (COVID-19)

2020 ◽  
Vol 27 (11) ◽  
pp. 3196-3207 ◽  
Author(s):  
Chiara Agrati ◽  
Alessandra Sacchi ◽  
Veronica Bordoni ◽  
Eleonora Cimini ◽  
Stefania Notari ◽  
...  
Keyword(s):  
Immune Response ◽  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Mononuclear Cells ◽  
Severe Disease ◽  
Suppressor Cells ◽  
Myeloid Derived Suppressor Cells ◽  
Cell Functions ◽  
Convalescent Phase

Abstract SARS-CoV-2 is associated with a 3.4% mortality rate in patients with severe disease. The pathogenesis of severe cases remains unknown. We performed an in-depth prospective analysis of immune and inflammation markers in two patients with severe COVID-19 disease from presentation to convalescence. Peripheral blood from 18 SARS-CoV-2-infected patients, 9 with severe and 9 with mild COVID-19 disease, was obtained at admission and analyzed for T-cell activation profile, myeloid-derived suppressor cells (MDSCs) and cytokine profiles. MDSC functionality was tested in vitro. In four severe and in four mild patients, a longitudinal analysis was performed daily from the day of admission to the early convalescent phase. Early after admission severe patients showed neutrophilia, lymphopenia, increase in effector T cells, a persisting higher expression of CD95 on T cells, higher serum concentration of IL-6 and TGF-β, and a cytotoxic profile of NK and T cells compared with mild patients, suggesting a highly engaged immune response. Massive expansion of MDSCs was observed, up to 90% of total circulating mononuclear cells in patients with severe disease, and up to 25% in the patients with mild disease; the frequency decreasing with recovery. MDSCs suppressed T-cell functions, dampening excessive immune response. MDSCs decline at convalescent phase was associated to a reduction in TGF-β and to an increase of inflammatory cytokines in plasma samples. Substantial expansion of suppressor cells is seen in patients with severe COVID-19. Further studies are required to define their roles in reducing the excessive activation/inflammation, protection, influencing disease progression, potential to serve as biomarkers of disease severity, and new targets for immune and host-directed therapeutic approaches.

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