Expansion of Lox-1+CD15+ myeloid-derived suppressor cells in hepatocellular carcinoma patients.

2017 ◽  
Vol 35 (7_suppl) ◽  
pp. 124-124 ◽  
Author(s):  
Xing Li ◽  
Qing-Jian Ye ◽  
Yan-Fang Xing ◽  
Jin-Xiang Lin ◽  
Qu Lin ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Cell Proliferation ◽  
T Cell ◽  
Whole Blood ◽  
Mrna Level ◽  
Suppressor Cells ◽  
Suppressor Cell ◽  
T Cell Proliferation ◽  
Dependent Manner ◽  
Ifn Γ

124 Background: The top issue in the field of myeloid deprived suppressor cell (MDSC) was lack of specific markers. Lox-1 was reported to be a novel marker for polymorphonuclear MDSC (PMN-MDSC) in whole blood of head and neck cancer and lung cancer patients. The present study is aimed to detecting the lox-1 PMN-MDSC in whole blood. Methods: In the present study, a series of 24 hepatocellular carcinoma (HCC) patients and 12 healthy donors were analyzed investigating frequencies of PMN-MDSC (Lox-1+CD15+) in whole blood. The immunosuppressive function of MDSC were evaluated using T cell proliferation and activation tests. The underly mechnisms were determined using inhibitors, genes expression and activity tests. The association between MDSC and clinical parameters were determined retrospectively. Results: Patients presented significantly higher level of PMN-MDSCs. In order to confirm immune suppressive capacity of PMN-MDSCs in HCC patients, circulative PMN-MDSCs and T cells were purified using flow sorting and cocultured. T cell proliferation was abrogated by the addition of PMN-MDSC with a dosage dependent manner, as well as the production of IFN-γ. Besides, the suppression on T cell proliferation and IFN-γ production was partially reversed by reactive oxygen species (ROS) inhibitor and Arginase inhibitor. The ROS level were higher in PMN-MDSC than their normal controls. The mRNA level of NOX2, the key protein complex responsible for ROS productin in MDSC, and Arginase I were higher in PMN-MDSCs. Finally, the frequencies of PMN-MDSCs was positively associated with tumor volume. Conclusions: The present study found that Lox-1+CD15+ were novel markers for PMN-MDSCs in whole blood and very easily to be standardized between institutions.

Endoplasmic reticulum stress induced Lox-1+ CD15+ polymorphonuclear myeloid-derived suppressor cells in hepatocellular carcinoma and associated with poor prognsis.

2018 ◽  
Vol 36 (5_suppl) ◽  
pp. 38-38
Author(s):  
Xing Li ◽  
Xiang-yuan Wu ◽  
Nan Jiang ◽  
Yan-Fang Xing ◽  
Jie Chen ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Cell Proliferation ◽  
T Cell ◽  
Binding Protein ◽  
Suppressor Cells ◽  
T Cell Proliferation ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Myeloid Derived Suppressor Cells ◽  
Ifn Γ

38 Background: A recent study indicated that Lectin-type oxidized LDL receptor-1 (LOX-1) was a distinct surface marker for human polymorphonuclears myeloid-derived suppressor cells (PMN-MDSC). The present study was aimed to investigate the existence LOX-1 PMN-MDSC in hepatocellular carcinoma (HCC) patients, the latent mechanism and their association with clinical parameters. Methods: 30 HCC patients and 30 health control were included. LOX-1+CD15+ PMN-MDSCs were investigated. Results: LOX-1+CD15+ PMN-MDSC were significantly elevated in both WB and PBMC of HCC patients compared with healthy control. LOX-1+CD15+ PMN-MDSC were more abundant in PBMC than WB. Addition of PMN-MDSCs resulted in significantly reduced proliferation and IFN-γ production of T cells with a dosage dependent manner. LOX-1-CD15+ PMNs present no suppressive function. The suppression on T cell proliferation and IFN-γ production was reversed by ROS inhibitor and Arginase inhibitor. ROS level of LOX-1+CD15+ PMN by DCFDA were higher in LOX-1+CD15+ PMN-MDSCs than LOX-1-CD15+ PMNs, as well as the mRNA levels of the NADPH oxidase NOX2. Meanwhile, the expression of arginase I and activity of arginase were also significantly raised in LOX-1+CD15+ PMN-MDSCs. LOX-1+CD15+ PMN-MDSCs displayed significantly higher expression of spliced X-box–binding protein 1 (sXBP1), ATF3 and CCAAT/enhancer binding protein (CHOP) were higher. For HCC patients, LOX-1+CD15+ PMN-MDSCs in WB were positively related to Cancer of the Liver Italian Program (CLIP) score. Conclusions: LOX-1+CD15+ PMN-MDSC were elevated in HCC patients and suppressed T cell proliferation through ROS/Arg I pathway with ER stress as a potential feature. LOX-1+CD15+ PMN-MDSC presented positive association with the prognosis of HCC patients.

scholarly journals Activated Circulating Myeloid-Derived Suppressor Cells in Patients with Dilated Cardiomyopathy

2016 ◽  
Vol 38 (6) ◽  
pp. 2438-2451 ◽  
Author(s):  
Wen-Cai Zhang ◽  
Yan-Ge Wang ◽  
Wen-Hui Wei ◽  
Xin Xiong ◽  
Kan-Ling Liu ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
T Cell ◽  
Dilated Cardiomyopathy ◽  
Suppressor Cells ◽  
Left Ventricular Ejection ◽  
T Cell Proliferation ◽  
Healthy Controls ◽  
Myeloid Derived Suppressor Cells ◽  
Hla Dr ◽  
Ifn Γ

Background/Aims: Myeloid-derived suppressor cells (MDSCs) are increased in inflammatory and autoimmune disorders. This study aims to evaluate the significance of MDSCs in dilated cardiomyopathy (DCM) patients. Methods: In total, 42 newly hospitalized DCM patients and 39 healthy controls were enrolled in the study. The frequencies of circulating CD14+HLA-DR-/low MDSCs were determined by flow cytometry. Then, the functional properties of MDSCs in suppressing T cell proliferation and interferon-gamma (IFN-γ) production were measured in a co-culture model. Then, mRNA expression levels of various important molecules in peripheral blood mononuclear cells were measured by real time polymerase chain reaction. Furthermore, correlation analyses between MDSC frequencies and cardiac function parameters were also performed. Results: The frequencies of circulating CD14+HLA-DR-/low MDSCs were significantly elevated in DCM patients compared with healthy controls. It showed that MDSCs from DCM patients more effectively suppressed T cell proliferation and IFN-γ production compared with those from healthy controls, which was partially mediated by arginase-1 (Arg-1). In addition, the correlation analysis suggested that MDSC frequencies were negatively correlated with left ventricular ejection fraction (LVEF), while positively with N-terminal pro-brain natriuretic peptide (NT-proBNP) in patients with DCM. Conclusions: Circulating activated MDSCs might play significant immunomodulatory roles in the pathogenesis of DCM.

scholarly journals INNV-32. SUPER-INDUCTION OF IMMUNOSUPPRESSIVE GLIOBLASTOMA EXTRACELLULAR VESICLES BY IFN-γ

2019 ◽  
Vol 21 (Supplement_6) ◽  
pp. vi137-vi137
Author(s):  
Mi-Yeon Jung ◽  
Benjamin Himes ◽  
Luz Cumba-Garcia ◽  
Ian Parney
Keyword(s):  
Cell Proliferation ◽  
T Cell ◽  
Extracellular Vesicles ◽  
Suppressor Cells ◽  
Primary Brain Tumor ◽  
T Cell Proliferation ◽  
L1 Data ◽  
Checkpoint Molecule ◽  
Ifn Γ

Abstract Glioblastoma (GBM) is the most common and aggressive primary brain tumor. Median survival is 15 months despite surgery, radiation, and chemotherapy. Immunotherapy is promising but GBM-mediated immunosuppression remains a barrier. Recently, extracellular vesicles (EVs) have been implicated in GBM-mediated immunosuppression through expression of the immune checkpoint molecule PD-L1. Data from our group has suggested this is predominantly through induction of immunosuppressive monocytes including myeloid-derived suppressor cells (MDSCs) and non-classical monocytes (NCMs). PD-L1 expression is increased in most nucleated cells following IFN-γ exposure. We, therefore, sought to determine if IFN-γ exposure would result in super-induction of immunosuppressive GBM EVs. EVs were harvested in vitro from matched differentiated and stem-like human GBM cell lines +/- IFN-γ. IFN-γ exposure did not alter EV production or expression of common EV markers but increased PD-L1 expression in EVs from differentiated but not stem-like GBM cells. In keeping with our earlier findings, no direct inhibition of T cell proliferation by stem-like or differentiated GBM EVs was observed regardless of IFN-γ exposure or PD-L1 expression. In contrast, differentiated but not stem-like GBM cell EVs induced MDSC and NCM differentiation from normal monocytes. This was increased following IFN-γ exposure and was dependent upon PD-L1 expression. Monocytes exposed to differentiated but not stem-like GBM cell EVs inhibited T cell proliferation in a similar manner (increased with IFN-γ exposure, decreased with PD-L1 knockdown). Thus, IFN-γ exposure results in super-induction of immunosuppressive EVs from differentiated but not stem-like GBM cells that increase MDSC and NCM differentiation in normal monocytes and increase their ability to inhibit T cell proliferation. These effects are dependent upon PD-L1 up-regulation induced by IFN-γ. This may be an important mechanism GBMs utilize to suppress anti-tumor T cell responses that are typically accompanied by increased IFN-γ expression.

473 Mavrilimumab, a human monoclonal antibody targeting GM-CSFRα, inhibits polarization to myeloid-derived suppressor cells (MDSCs) that express PD-L1 and restores T-cell proliferation in vitro

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A504-A504
Author(s):  
Luis Carvajal ◽  
Luciana Gneo ◽  
Carmela De Santo ◽  
Matt Perez ◽  
Tracy Garron ◽  
...  
Keyword(s):  
Pancreatic Cancer ◽  
Cell Proliferation ◽  
T Cell ◽  
Cancer Cell ◽  
Suppressor Cells ◽  
T Cell Proliferation ◽  
Myeloid Derived Suppressor Cells ◽  
Gm Csf ◽  
Macrophage Colony Stimulating Factor ◽  
Macrophage Colony

BackgroundMyeloid-derived suppressor cells (MDSCs) accumulate in the blood and tumor microenvironment (TME) and suppress anti-tumor immune responses.1 Cancer cells express the granulocyte-macrophage colony-stimulating factor (GM-CSF), which drives MDSC differentiation and function.2 3 4 It is upregulated in several cancers, including mesothelioma, pancreatic and colorectal, and it is linked to higher levels of intra-tumoral MDSCs and poorer overall survival.2 4 5 In animal models, knockdown of GM-CSF in pancreatic epithelium or pancreatic mesenchymal stem cells inhibits tumorigenesis, reduces intra-tumor MDSCs and enhances CD8+ T cell accumulation.6 7 8 Therefore, targeting the GM-CSF receptor alpha (GM-CSFRα) on MDSCs is an attractive strategy to restore anti-tumor immunity. Mavrilimumab is a clinical stage fully human monoclonal antibody that blocks GM-CSFRα. It has demonstrated efficacy and acceptable safety profile in patients with rheumatoid arthritis, and it’s currently undergoing investigation in phase II studies in giant cell arteritis and in patients with severe COVID-19 pneumonia and hyper-inflammation (NCT03827018, NCT04397497, respectively). The present study investigates its potential as a therapeutic strategy to target MDSCs in the TME as an adjuvant to immunotherapy.MethodsCancer cell supernatants were collected when cells reached confluency. Human GM-CSF was measured by ELISA. Healthy donor CD14+ monocytes were incubated (± mavrilimumab) with cancer cell supernatants for either 3 or 6 days followed by phenotypic analysis (CD14, CD33, HLA-DR, CD11b, CD206, CD80, PD-L1, Arginase-1) by flow cytometry. On day 3, autologous CD3+ T cells were stimulated with CD3/CD28 and IL-2 and co-cultured with putative MDSCs for 5 days. T-cell proliferation was evaluated by measuring carboxyfluorescein succinimidyl ester (CFSE) dilution in CD4+ and CD8+ T cells by flow cytometry.ResultsGM-CSF is expressed in the supernatant of cancer cell lines (HCT116, SW-480, Panc-1, Capan-1). Human monocytes cultured with conditioned medium from colorectal carcinoma (SW-480) or pancreatic adenocarcinoma (Capan-1) show downregulation of HLA-DR, increased expression of PD-L1, Arg-1, CD206, and can suppress T-cell proliferation in-vitro. Similarly, peripheral blood monocytes purified from pancreatic cancer patients suppress T-cell proliferation ex-vivo. Notably, Mavrilimumab inhibits the polarization of healthy donor monocytes to M-MDSCs and restores T-cell proliferation.ConclusionsTargeting of GM-CSFRα with mavrilimumab may alleviate the pro-tumorigenic and immunosuppressive functions of MDSCs in the TME. Future clinical studies should evaluate whether targeting of the GM-CSFRα in combination with immune checkpoint inhibitors is a viable therapeutic option to bolster their efficacy.Ethics ApprovalThe study was approved by the Institute of Immunology and Immunotherapy, University of Birmingham, UK Ethics Board. Healthy volunteer human material was obtained from commercial sources and approved by Stemexpress Institutional Review Board (IRB).ReferencesLaw AMK, Valdes-Mora F, Gallego-Ortega D. Myeloid-Derived Suppressor Cells as a Therapeutic Target for Cancer. Cells 2020;9(3):561.Khanna S, Graef S, Mussai F, et al. Tumor-Derived GM-CSF Promotes Granulocyte Immunosuppression in Mesothelioma Patients. Clin Cancer Res 2018;24(12):2859–2872.Dolcetti L, Peranzoni E, Ugel S, et al. Hierarchy of immunosuppressive strength among myeloid-derived suppressor cell subsets is determined by GM-CSF. Eur J Immunol 2010;40(1):22–35.Takeuchi S, Baghdadi M, Tsuchikawa T, et al. Chemotherapy-derived inflammatory responses accelerate the formation of immunosuppressive myeloid cells in the tissue microenvironment of human pancreatic cancer. Cancer Res 2015;75(13):2629–2640.Chen Y, Zhao Z, Chen Y, et al. An epithelial-to-mesenchymal transition-inducing potential of granulocyte macrophage colony-stimulating factor in colon cancer. Sci Rep 2017;7(1):8265.Bayne LJ, Beatty GL, Jhala N, et al. Tumor-derived granulocyte-macrophage colony-stimulating factor regulates myeloid inflammation and T cell immunity in pancreatic cancer. Cancer Cell 2012;21(6):822–835.Pylayeva-Gupta Y, Lee KE, Hajdu CH, Miller G, Bar-Sagi D. Oncogenic Kras-induced GM-CSF production promotes the development of pancreatic neoplasia. Cancer Cell 2012;21(6):836–847.Waghray M, Yalamanchili M, Dziubinski M, et al. GM-CSF mediates mesenchymal-epithelial cross-talk in pancreatic cancer. Cancer Discov 2016;6(8):886–899.

scholarly journals Amygdalin promotes the activity of T cells to suppress the progression of HBV-related hepatocellular carcinoma via the JAK2/STAT3 signaling pathway

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Ruoyu Wang ◽  
Dong Zhang ◽  
Kewei Sun ◽  
Jianping Peng ◽  
Wenfang Zhu ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Cell Proliferation ◽  
T Cells ◽  
T Cell ◽  
Cell Viability ◽  
Caspase 3 ◽  
Invasion And Migration ◽  
Ifn Γ ◽  
And Migration ◽  
Cellular Immune

Abstract Background Hepatitis B virus (HBV) infection is a high-risk factor of hepatocellular carcinoma (HCC). Cellular immune responses are essential for HCC development, and the CD4+ and CD8+ T subtypes are identified as the primary anti-tumor immune cells. In the study, we investigated the effect and mechanism of amygdalin in the cellular immune response in HBV-related HCC and HCC progression. Methods The cell proliferation was examined by MTT analysis. Cells metastasis ability was detected by Invasion and migration assays. Quantification of apoptotic cells was performed with Flow cytometer assay. The protein levels of p-STAT3, STAT3, p-JAK2, JAK2, caspase-3, cleaved caspase-3 were detected by performing immunoblotting assays. Results We demonstrate that amygdalin treatment could rescue the HBV-T cell viability and IFN-γ and TNF-αproduction. In HBV-T cells, the MFI levels of CD8+ are lower than that in NC-T cells. Moreover, the phosphorylation levels of STAT3 and JAK2 are higher in HBV-T cells, compared to those in NC-T cells, and then reduced by amygdalin treatment. Co-culture with HBV-T cells could reduce IFN-γ and TNF-α, production while increase IL-6 and IL-10 production in HepG2.2.15 cells; these alterations could be partially reversed by amygdalin pretreatment. Finally, co-culture with HBV-T cells significantly promoted the cell viability, inhibited the apoptosis, and promoted the migration of HepG2.2.15 cells, and these alterations could be partially reversed by amygdalin treatment. Conclusion Our findings provide a rationale for further studies on the functions and mechanism of amygdalin inhibiting HBV-related HCC cell proliferation, invasion, and migration via T cell-mediated tumor immunity.

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 IMMU-36. THE ROLE OF PD-L1 IN GLIOBLASTOMA-DERIVED EXTRACELLULAR VESICLES IN THE INDUCTION OF IMMUNOSUPPRESSIVE MONOCYTES

2019 ◽  
Vol 21 (Supplement_6) ◽  
pp. vi126-vi127
Author(s):  
Benjamin Himes ◽  
Timothy Peterson ◽  
Jasmine Tyson ◽  
Helen Lee ◽  
Tristan deMooij ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
T Cell ◽  
Extracellular Vesicles ◽  
Suppressor Cells ◽  
Primary Brain Tumor ◽  
T Cell Proliferation ◽  
Great Promise ◽  
Substantial Impact ◽  
Constitutive Overexpression ◽  
Novel Therapeutic Strategies

Abstract Glioblastoma (GBM) is the most common and lethal primary brain tumor, and novel therapeutic strategies that make a substantial impact on outcomes are sorely needed. Immunotherapies have shown great promise in the treatment of a number of cancers in recent year, and a concerted effort is being made to apply these treatment paradigms to GBM. However, many GBM patients exhibit profound immunosuppression, likely limiting the efficacy of such approaches. The mechanisms of this immunosuppression are poorly understood, but tumor-derived extracellular vesicles (EVs), may play a role. We demonstrate that GBM-derived EVs induce the development of myeloid-derived suppressor cells (MDSCs) and non-classical monocytes (NCMs). We further demonstrate that these EV-induced monocytic cells are immunosuppressive, resulting in impaired T cell proliferation upon co-culture. We found that the immunosuppressive effects of tumor-derived EVs appear to be driven by the induction of these immunosuppressive monocytes, as EV treatment of T cells did not significantly impact T cell proliferation. Further, we sought to characterize the important of programmed death ligand 1 (PD-L1) in the induction of these immunosuppressive monocyte populations. We found PD-L1 to be expressed in the EVs from GBM cell lines, and that modulation in PD-L1 expression via either constitutive overexpression or shRNA-mediated knockdown resulted in concordant changes in expression in tumor-derived EVs. We demonstrate that PD-L1 is important for the induction of NCM but not for MDSCs. Taken together, these findings point to a significant role for tumor-derived EVs in the induction of immunosuppressive monocytes in GBM, and that these cells may be a driving force of systemic immunosuppression. PD-L1 is one factor expressed in EVs that has immunomodulatory properties, but additional EV cargo likely plays a major role in the induction of immunosuppressive cells.

scholarly journals The Role of Interleukin-10 (IL-10) in IL-15–Mediated T-Cell Responses

Blood ◽  
1997 ◽  
Vol 90 (11) ◽  
pp. 4513-4521 ◽  
Author(s):  
Dieter Körholz ◽  
Ursula Banning ◽  
Halvard Bönig ◽  
Markus Grewe ◽  
Marion Schneider ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
T Cells ◽  
T Cell ◽  
Interleukin 10 ◽  
T Cell Proliferation ◽  
Cell Production ◽  
Cd25 Expression ◽  
Tnf Α ◽  
Ifn Γ

Abstract Interleukin-15 (IL-15) is a potent T-cell stimulating factor, which has recently been used for pre-clinical in vivo immunotherapy. Here, the IL-15 effect on CD3-stimulated peripheral human T cells was investigated. IL-15 induced a significant T-cell proliferation and upregulated CD25 expression. IL-15 significantly enhanced T-cell production of interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), and IL-10. Between 10- and 100-fold greater concentrations of IL-15 were necessary to reach a biological effect equivalent to that of IL-2. Blockade of IL-2 binding to the high-affinity IL-2 receptor did not affect the IL-15 effects, suggesting that IL-15 did not act by inducing endogenous IL-2. Exogenously administered IL-10 significantly reduced the IL-15 and IL-2–mediated IFN-γ and TNF-α production, whereas T-cell proliferation and CD25 expression were not affected. The inhibitory effects of exogenously administered IL-10 on T-cell cytokine production appeared indirect, and are likely secondary to decreased IL-12 production by accessory cells. Inhibition of endogenous IL-10 binding to the IL-10 receptor significantly increased IFN-γ and TNF-α release from T cells. These data suggest that endogenous IL-10 can regulate activated T-cell production of IFN-γ and TNF-α via a paracrine negative feedback loop. The observations of this study could be of relevance for the therapeutic use of IL-15 in vivo.

Nitric oxide-producing CD11b+Ly-6G(Gr-1)+CD31(ER-MP12)+cells in the spleen of cyclophosphamide–treated mice: implications for T-cell responses in immunosuppressed mice

Blood ◽  
2000 ◽  
Vol 95 (1) ◽  
pp. 212-220 ◽  
Author(s):  
Iñigo Angulo ◽  
Federico Gómez de las Heras ◽  
José F. Garcı́a-Bustos ◽  
Domingo Gargallo ◽  
M. Angeles Muñoz-Fernández ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Cell Proliferation ◽  
T Cell ◽  
T Cell Responses ◽  
T Cell Proliferation ◽  
Intensive Chemotherapy ◽  
Suppressive Activity ◽  
Cell Responses ◽  
Nos Inhibitors ◽  
Ifn Γ

Abstract During recovery from intensive chemotherapy with cyclophosphamide (CTX), mice suffer a severe but transitory impairment in spleen cell proliferation to T-cell mitogens (Con A or anti-CD3 plus IL-2). Although CTX treatment reduced spleen T-cell cellularity, this cannot fully account for T-cell unresponsiveness. The results showed that CTX induces the colonization of spleen by an immature myeloid CD11b+Ly-6G+CD31+ population. Its presence closely correlated with the maximum inhibition of T-cell proliferation. Moreover, this suppressive activity was dependent on nitric oxide (NO) production in cultures since (1) higher amounts of nitric oxide and inducible nitric oxide synthase (iNOS) mRNA were produced in CTX spleen cells (CTX-SC) than in control splenocyte cultures and (2) NOS inhibitors greatly improved the proliferation of T lymphocytes. Nitric oxide production and suppressive activity were also dependent on endogenous interferon-γ (IFN-γ) production since anti–IFN-γ abrogated both effects. Finally, iNOS protein expression was restricted to a heterogeneous population of CD31+cells in which CD11b+Ly-6G+ cells were required to suppress T-cell proliferation. These results indicated that CTX might also cause immunosuppression by a mechanism involving the presence of immature myeloid cells with suppressor activity. This may have implications in clinical praxis since inappropriate immunotherapies in patients treated with intensive chemotherapy could lead to deleterious T-cell responses. (Blood. 2000;95:212-220)

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