髓系来源抑制细胞的功能及其与自身免疫性疾病关系的研究进展

髓系来源抑制细胞(MDSC)是一群具有异质性的髓系细胞,在肿瘤、感染、创伤和自身免疫性疾病等病理状态下,会异常扩增并发挥免疫抑制作用。MDSC主要通过上调诱导型一氧化氮合酶(iNOS)和精氨酸酶(Arg)的表达,增加一氧化氮(NO)、活性氧(ROS)和过氧化硝酸盐(ONOO-)浓度,诱导调节性T细胞(Treg)分化等途径抑制获得性免疫;通过削弱自然杀伤(NK)细胞功能等途径抑制固有免疫。近年来MDSC在自身免疫性疾病中的作用日渐受到关注,参与了多发性硬化等多种自身免疫性疾病的免疫调控。现就MDSC及其与自身免疫性疾病关系的研究进展进行综述。     

舒尼替尼对转移性肾癌患者髓系来源抑制细胞的影响

舒尼替尼是一种口服的多靶点酪氨酸激酶抑制剂,具有抗血管生成和抑制肿瘤增殖的作用.与IFN-α相比,舒尼替尼明显提高了转移性肾癌(mRCC)患者的无进展生存期,并成为治疗mRGC的一线治疗方案.近期有研究报道,舒尼替尼还可以通过抑制髓系来源抑制细胞(MDSC)调节肿瘤免疫.MDSC是一群来源于髓系细胞谱系的异质细胞,其通...     

肿瘤微环境髓源性抑制细胞与T淋巴细胞的相互作用的研究进展北大核心CSCD

髓源性抑制细胞(MDSC)是一类免疫系统来源的、具有功能多样性的异质性细胞群,能通过多途径抑制T淋巴细胞介导的抗肿瘤免疫,促进肿瘤发生、发展。T细胞并非只接受MDSC的单向调节,而是存在多个反馈调节机制,二者的相互作用形成促进肿瘤发生、发展的重要因素。近年来关于γ干扰素(IFN-γ)、转化生长因子β(TGF-β)、诱导型一氧化氮合酶(i NOS)、白细胞介素17(IL-17)、精氨酸酶1、外泌体及微小RNA参与MDSC与T细胞间信号交流及调控它们细胞生物学行为的作用有了进一步阐述。但是肿瘤微环境中T细胞如何干预MDSC生物学行为的相关机制及信号通路仍缺少深入的探究。我们总结了肿瘤微环境中MDSC与T细胞之间的相互作用及相关机制的研究进展。     

肿瘤微环境髓源性抑制细胞与T淋巴细胞的相互作用的研究进展

髓源性抑制细胞(MDSC)是一类免疫系统来源的、具有功能多样性的异质性细胞群,能通过多途径抑制T淋巴细胞介导的抗肿瘤免疫,促进肿瘤发生、发展。T细胞并非只接受MDSC的单向调节,而是存在多个反馈调节机制,二者的相互作用形成促进肿瘤发生、发展的重要因素。近年来关于γ干扰素(IFN-γ)、转化生长因子β(TGF-β)、诱导型一氧化氮合酶(i NOS)、白细胞介素17(IL-17)、精氨酸酶1、外泌体及微小RNA参与MDSC与T细胞间信号交流及调控它们细胞生物学行为的作用有了进一步阐述。但是肿瘤微环境中T细胞如何干预MDSC生物学行为的相关机制及信号通路仍缺少深入的探究。我们总结了肿瘤微环境中MDSC与T细胞之间的相互作用及相关机制的研究进展。     

肿瘤微环境中髓系来源抑制细胞对T细胞免疫活性抑制的分子机制

髓系来源抑制细胞(MDSC)根据其起源和功能而命名,由巨噬细胞、树突状细胞(DC)及粒细胞等细胞的前体细胞组成。肿瘤免疫逃逸与肿瘤微环境中MDSC介导的抗肿瘤免疫抑制相关,肿瘤微环境中的MDSC主要通过抑制T细胞的免疫活性来发挥免疫抑制作用。根据MDSC与T细胞之间的接触方式,肿瘤微环境中的MDSC抑制T细胞免疫功能的分子机制可分为直接抑制和间接抑制两类,其中MDSC通过产生细胞因子影响T细胞功能和细胞之间膜受体配体相互作用发挥抑制T细胞功能的方式为直接抑制,而MDSC通过影响T细胞代谢从而影响T细胞功能及通过其他细胞发挥抑制T细胞功能的方式为间接抑制。制定针对MDSC的治疗策略时,需综合考虑上述多种分子机制共存的可能性。     

肿瘤相关树突状细胞、巨噬细胞和髓系抑制细胞的研究进展

肿瘤能够通过多种机制有效逃避机体的免疫反应,这些机制不仅涉及肿瘤细胞本身,而且与宿主免疫反应功能受损有关.肿瘤相关树突状细胞(TADC)、髓系来源抑制细胞(MDSC)和肿瘤相关巨噬细胞(TAM)等在肿瘤免疫逃逸过程中能够诱导免疫抑制反应,这些研究将会为抗肿瘤免疫治疗提供可能的新策略.     

肿瘤源性因子对肿瘤相关免疫抑制细胞的影响

肿瘤相关树突状细胞(TADC)、髓系来源抑制细胞(MDSC)和肿瘤相关巨噬细胞(TAM)等免疫抑制细胞在肿瘤免疫逃逸过程中能够诱导免疫抑制反应.肿瘤源性因子不仅影响这些细胞的分化和功能,而且影响这些细胞的迁移.这些在肿瘤免疫中的研究进展能够为发展新的抗肿瘤免疫治疗策略提供依据.     

MDSC在自身免疫疾病中的作用

髓系抑制细胞（Myeloid derived suppressor cells,MDSC）是具有抑制功能的髓系来源的细胞群。在自身免疫疾病中,MDSC显著增多,并在体外有抑制功能,然而在体内研究中,MDSC的研究存在争议。最新研究发现具有抑制功能的MDSC的显著增多并不能有效缓解自身免疫疾病,而且在某些情况下甚至促进疾病的进展。因此,MDSC在自身免疫疾病的作用有待进一步研究。本文根据已有文献,综述了MDSC在不同的自身免疫疾病中的改变及机制。     

MDSC对免疫系统的抑制机制

机体的免疫系统是一个复杂的网络调控系统,由固有免疫和适应性免疫组成,其中包括了固有免疫细胞、抗原递呈细胞、适应性免疫细胞等之间的相助作用和调节。越来越多的证据表明一群骨髓来源的具有CD11b和Gr-1标志的抑制性细胞在各种感染、肿瘤、急慢性炎症等疾病中大量存在,并且负向调节机体的免疫功能。这就是具有负向调节机体免疫反应的髓系抑制性细胞(MDSC),近年来被广泛研究。MDSC是免疫系统调节机体免疫反应的一群独特的细胞群体,可以对多种免疫细胞通过多种不同的机制发挥免疫抑制功能,从而导致机体固有免疫和适应性免疫功能的低下,促进疾病的发展和恶化。本文着重就MDSC对参与机体免疫反应的几种炎性细胞的抑制     

肿瘤相关免疫抑制细胞的免疫逃逸作用机制

肿瘤能够通过多种机制有效逃避机体免疫系统监视,肿瘤相关树突状细胞（TADC）、髓系来源抑制细胞（MDSC）、肿瘤相关巨噬细胞（TAM）等在肿瘤免疫逃逸过程中能够诱导免疫抑制反应。虽然由TADC、MDSC和TAM介导的免疫抑制机制还不完全明了,但是最近的研究表明肿瘤相关因子激活的细胞内信号传导途径可以调节细胞内代谢、细胞因子的产生和共刺激分子及共抑制分子的表达,由此产生免疫抑制作用。     

髓系抑制细胞抑制机体抗肿瘤免疫机制及相关免疫治疗的研究进展

髓系抑制细胞为未成熟的髓系细胞,在肿瘤组织中大量聚集。髓系抑制细胞可通过多种机制抑带0细胞毒性T细胞和自然杀伤细胞。自然杀伤T细胞对肿瘤的杀伤或通过诱导调节性T细胞（Treg）抑制机体抗肿瘤免疫从而促进肿瘤进展,因而抑制髓系抑制细胞将成为肿瘤免疫治疗的新靶点。     

PGE2-Driven Induction and Maintenance of Cancer-Associated Myeloid-Derived Suppressor Cells

Myeloid-derived suppressor cells (MDSCs) are critical mediators of tumor-associated immune suppression, with their numbers and activity strongly increased in most human cancers and animal models. MDSCs suppress anti-tumor immunity through multiple mechanisms, including the manipulation of arginine and tryptophan metabolism by such factors as arginase (Arg), inducible nitric oxide synthase (iNOS/NOS2), and indoleamine-2,3-dioxygenase (IDO). Prostaglandin E₂ (PGE₂), a mediator of chronic inflammation and tumor progression, has emerged as a key molecule in MDSC biology. PGE₂ promotes MDSC development and their induction by additional factors, directly suppresses T cell immune responses and participates in the induction of other MDSC-associated suppressive factors, including Arg, iNOS and IDO. It further promotes MDSC recruitment to tumor environments through the local induction of CXCL12/SDF-1 and the induction and stabilization of the CXCL12 receptor, CXCR4, on tumor-associated MDSCs. The establishment of a positive feedback loop between PGE₂ and cyclooxygenase 2 (COX-2), the key regulator of PGE₂ synthesis, stabilizes the MDSC phenotype and is required for their suppressive function. The central role of PGE₂ in MDSC biology provides for a feasible target for counteracting MDSC-mediated immune suppression in cancer.     

Immunomodulatory effects of myeloid-derived suppressor cells in diseases: Role in cancer and infections

Myeloid-derived suppressor cells (MDSCs) are heterogeneous cells capable of abrogating T and B cells responses and have been identified in numerous cancers. As with other regulatory cell populations, they aim to maintain balance between host-defence-associated inflammation and ensuing tissue pathology. MDSC accumulation and/or activation involve several growth factors and cytokines including Granulocyte Macrophage-Colony Stimulating Factor (GM-CSF) and Interleukin (IL)-6 and suppression has been linked to receptors such as IL-4Rα. Other immune pathways, such as Toll-like receptors (TLRs) have also been shown to interfere in MDSC activity adding to the complexity in clarifying their pathways. Monocytic- (Mo-MDSCs) and polymorphonuclear- (PMN-MDSCs) cells are two subsets of MDSCs that have been well characterized and have been shown to function through different mechanisms although both appear to require nitric oxide. In human and murine model settings, MDSCs have been shown to have inhibitory effects on T cell responses during bacterial, parasitic and viral pathologies and an increase of MDSC numbers has been associated with pathological conditions. Interestingly, the environment impacts on MDSC activity and regulatory T cells (Tregs), mast cells and a few cells that may help MDSC in order to regulate immune responses. Since the majority of pioneering data on MDSCs has stemmed from research on malignancies, this review will summarize MDSC biology and function in cancer and highlight current knowledge about these cells during infectious pathologies as well.     

In vivo suppressive function of myeloid-derived suppressor cells is limited to the inflammatory site

Current paradigms suggest that, despite the heterogeneity of myeloid-derived suppressor cells (MDSC), all Gr-1(+) CD11b(+) cells can exert suppressive function when exposed to inflammatory stimuli. In vitro evaluation shows that MDSC from multiple tissue sites have suppressive activity, and in vivo inhibition of MDSC enhances T-cell function; however, the relative capacity of MDSC present at localized inflammatory sites or in peripheral tissues to suppress T-cell responses in vivo has not been directly evaluated. In the current study, we observed that during a tissue-specific inflammatory response, MDSC inhibition of CD8(+) T-cell proliferation and IFN-γ production was restricted to the inflammatory site. Using a prostate-specific inflammatory model and a heterotopic prostate tumor model, we showed that MDSC from inflammatory sites or from tumor tissue possess immediate capacity to inhibit T-cell function, whereas those isolated from peripheral tissues (spleens and liver) were not suppressive without activation of iNOS by exposure to IFN-γ. These data suggest that MDSC are important regulators of immune responses in the prostate during acute inflammation and the chronic inflammatory setting of tumor growth, and that regulation of T-cell function by MDSC during a localized inflammatory response is restricted in vivo to the site of an ongoing immune response.     

The role of interleukin-12 on modulating myeloid-derived suppressor cells, increasing overall survival and reducing metastasis

Myeloid-derived suppressor cells (MDSC) are important to the tumour microenvironment as they actively suppress the immune system and promote tumour progression and metastasis. These cells block T-cell activation in the tumour microenvironment, preventing anti-tumour immune activity. The ability of a treatment to alter the suppressive function of these cells and promote an immune response is essential to enhancing overall therapeutic efficacy. Interleukin-12 (IL-12) has the potential not only to promote anti-tumour immune responses but also to block the activity of cells capable of immune suppression. This paper identifies a novel role for IL-12 as a modulator of MDSC activity, with implications for IL-12 as a therapeutic agent. Treatment with IL-12 was found to alter the suppressive function of MDSC by fundamentally altering the cells. Interleukin-12-treated MDSC exhibited up-regulation of surface markers indicative of mature cells as well as decreases in nitric oxide synthase and interferon-γ mRNA both in vitro and in vivo. Treatment with IL-12 was also found to have significant therapeutic benefit by decreasing the percentage of MDSC in the tumour microenvironment and increasing the percentage of active CD8(+) T cells. Treatment with IL-12 resulted in an increase in overall survival accompanied by a reduction in metastasis. The findings in this paper identify IL-12 as a modulator of immune suppression with significant potential as a therapeutic agent for metastatic breast cancer.     

IL-1β regulates a novel myeloid-derived suppressor cell subset that impairs NK cell development and function

Chronic inflammation is associated with promotion of malignancy and tumor progression. Many tumors enhance the accumulation of myeloid-derived suppressor cells (MDSC), which contribute to tumor progression and growth by suppressing anti-tumor immune responses. Tumor-derived IL-1β secreted into the tumor microenvironment has been shown to induce the accumulation of MDSC possessing an enhanced capacity to suppress T cells. In this study, we found that the enhanced suppressive potential of IL-1β-induced MDSC was due to the activity of a novel subset of MDSC lacking Ly6C expression. This subset was present at low frequency in tumor-bearing mice in the absence of IL-1β-induced inflammation; however, under inflammatory conditions, Ly6C(neg) MDSC were predominant. Ly6C(neg) MDSC impaired NK cell development and functions in vitro and in vivo. These results identify a novel IL-1β-induced subset of MDSC with unique functional properties. Ly6C(neg) MDSC mediating NK cell suppression may thus represent useful targets for therapeutic interventions.     

MDSC subtypes and CD39 expression on CD8+ T cells predict the efficacy of anti-PD-1 immunotherapy in patients with advanced NSCLC

The major suppressive immune cells in tumor sites are myeloid derived suppressor cells (MDSCs), tumor-associated macrophages (TAMs), and Treg cells, and the major roles of these suppressive immune cells include hindering T-cell activities and supporting tumor progression and survival. In this study, we analyzed the pattern of circulating MDSC subtypes in patients with non-small cell lung cancer (NSCLC) whether those suppressive immune cells hinder T-cell activities leading to poor clinical outcomes. First, we verified PMN-MDSCs, monocytic-MDSCs (M-MDSCs), and Treg cells increased according to the stages of NSCLC, and MDSCs effectively suppressed T-cell activities and induced T-cell exhaustion. The analysis of NSCLC patients treated with anti-PD-1 immunotherapy demonstrated that low PMN-MDSCs, M-MDSCs, and CD39⁺CD8⁺ T cells as an individual and all together were associated with longer progression free survival and overall survival, suggesting PMN-MDSCs, M-MDSCs, and CD39⁺CD8⁺ T cells frequencies in peripheral blood might be useful as potential predictive and prognostic biomarkers.     

Systemic injection of TLR1/2 agonist improves adoptive antigen-specific T cell therapy in glioma-bearing mice

Adoptive immunotherapy is an attractive strategy for glioma treatment. However, some obstacles still need be overcome. In this study, GL261-bearing mice treated with adoptively transferred antigen-specific T cells and systemic injection of bacterial lipoprotein (BLP), a TLR1/2 agonist, got a long-term survival and even immune protection. By analyzing adoptive T cells, it was found that BLP maintained T cell survival, proliferation and anti-tumor efficacy in the brains of tumor-bearing hosts. Moreover, tumor microenvironment was modified by up-regulating IFN-γ-secreting CD8+ T cells and down-regulating MDSC, which might be related with high CXCL10 and low CCL2 expression. In addition, TLR2 deficiency abrogated therapeutic effect with increased MDSC accumulation and decreased IFN-γ-secreting CD8+ T cells in the brains. Thus, the systemic injection of BLP could improve the adoptive T cell therapy by maintaining T cell persistence, modifying the tumor microenvironment and even inducing systemic anti-tumor immunity, which might offer a clinically promising immunotherapeutic strategy for glioma.     

髓样抑制细胞免疫抑制机理的研究

目的:研究荷瘤小鼠来源的髓样抑制细胞(Myeloid derived suppressor cell,MDSC)在肿瘤免疫抑制中的作用机理。方法:用Percoll分离法从荷瘤小鼠的脾脏和骨髓中分离Gr-1+CD11b+MDSC;用流式细胞术检测MDSC对T细胞增殖的抑制作用;分别用生化法和ELISA技术检测MDSC体外培养上清中抑制性因子NO、ROS和IL-10、TGF-β的含量。结果:MDSC在荷瘤小鼠的脾脏和骨髓中聚集增多,且其在骨髓中所占的比例显著高于脾脏;MDSC可以明显抑制脾脏细胞的增殖,体外培养6小时的MDSC可以分泌大量NO、ROS和IL-10、TGF-β。结论:本实验进一步证实MDSC可以通过分泌大量NO、ROS和IL-10、TGF-β抑制T细胞增殖。