树突状细胞及其在白血病中的免疫治疗

树突状细胞是最强的专职抗原提呈细胞,近年来对其亚群、迁移机制、选择性活化Th1/Th2细胞、启动不同的免疫应答类型和在白血病免疫治疗中的作用进行了大量的研究。本文就这方面的研究进展进行综述。     

晚期肺癌患者化疗后外周血T细胞CD8＋CD28-的表达及意义

细胞免疫是机体抗肿瘤免疫的主要方式,而T淋巴细胞是细胞免疫中的主要效应细胞。宿主免疫功能下降,受抑制或免疫缺陷时,肿瘤的发病率就明显增高,而恶性肿瘤患者的免疫功能则往往受到抑制。     

晚期肺癌患者化疗后外周血T细胞CD_8~+CD_(28)~-的表达及意义

细胞免疫是机体抗肿瘤免疫的主要方式,而T淋巴细胞是细胞免疫中的主要效应细胞.宿主免疫功能下降,受抑制或免疫缺陷时,肿瘤的发病率就明显增高,而恶性肿瘤患者的免疫功能则往往受到抑制.本文采用流式细胞技术对晚期肺癌患者外周血中CD8+CD28- T细胞、CD8+CD28+ T细胞的表达情况进行检测,旨在探讨此类细胞在肺癌细胞免疫中所发挥的作用.     

树突状细胞与乙型肝炎病毒感染的研究

树突状细胞(DC)是人体内抗原递呈能力最强的细胞[1],也是惟一能激活初始化T淋巴细胞的抗原提呈细胞(APC),其功能状态直接影响细胞免疫和体液免疫应答,在抗病毒的细胞免疫中起重要作用[2-3],同时在诱导免疫耐受和参与免疫应答的调节中也起着重要作用[4-5].     

肝脏间质树突状细胞在多器官功能障碍综合征中的变化与意义

目的探讨肝脏间质树突状细胞在多器官功能障碍综合征（MODS）免疫紊乱机制中的影响与作用。方法150只C57BL／6小鼠经腹腔注射酵母多糖复制MODS模型，随机分为正常对照组和致伤后3～6h、12～48h、5～7d及10～12d组。观察各组小鼠肝脏间质树突状细胞的形态学变化及其表面标记物CD11c、CD205、CD80和I—A^B的表达水平；用流式细胞术检测各组外周血CD4^＋与CD8^＋的T细胞数量及CD4’／CD8’比值。结果急性损伤期（12～48h）肝脏间质树突状细胞大量增生，CD11c、CD205、CD80和I—A^b表达均较正常对照组显著上升（P均〈0．01），外周血T细胞CD4^＋／CD8^＋比值则明显下降（P〈O．01）；功能衰竭期（10～12d）肝脏间质树突状细胞继续增生，但CD205、CD80和I—A^b表达较急性损伤期显著减少（P〈0．05或P〈0．01），外周血T细胞CD4^-／CD8^＋比值下降至最低。结论肝脏间质树突状细胞参与并影响了MODS中肝脏局部与全身免疫失衡及免疫抑制过程。     

血管免疫母细胞性T细胞淋巴瘤患者外周血淋巴细胞亚群检测的临床意义

目的 分析血管免疫母细胞性T细胞淋巴瘤(AITL)患者诊断时外周血淋巴细胞亚群与临床预后的相关性及其化疗后的动态变化。方法 回顾性分析2016年3月至2021年9月就诊于苏州大学附属第三医院的16例初治AITL患者的临床资料,以同期10例健康人群的淋巴细胞亚群结果为对照组。采用Kaplan-Meier法及COX回归模型进行生存分析。采用ROC曲线计算CD4/CD8临界值,并将患者分为低CD4/CD8组和高CD4/CD8组。结果 与对照组相比,AITL患者诊断时外周血中CD3⁺T细胞、CD4⁺T细胞、CD3⁺CD25⁺活化T细胞计数及CD4/CD8比值明显降低;同时,CD19⁺B细胞、CD20⁺B细胞、CD5⁺CD19⁺及CD19⁺CD23⁺活化B细胞计数皆明显降低。在第一疗程化疗后,患者CD3⁺T细胞比例较初诊时明显升高,在完成3疗程治疗后,CD4...     

外周血CD4/CD8 双阳性T细胞在类风湿性关节炎中的表达及意义

目的分析类风湿性关节炎(rheumatoid arthritis,RA)患者外周血CD4/CD8双阳性T细胞(double positive T cells,DPT)的表达水平及功能,并探讨DPT在RA发病中的作用。方法通过流式细胞术检测25例RA患者及25例健康人对照外周血CD3~+细胞中CD4~+/CD8~+双阳性细胞的比例;ELISA法检测RA患者及健康人对照血清中抗环瓜氨酸肽抗体(ACCP)、IL-6、TNF-α、IFN-γ和IL-12的表达水平,全自动生化分析仪检测C反应蛋白(CRP)、类风湿因子(RF)。结果与健康人对照组相比,RA患者组DPT占CD3+T细胞的比例明显升高,两组间差异具有统计学意义(t=4.63,P0.01);RA患者组的ESR、CRP、RF、ACCP、IL-6和TNF-α水平均高于健康人对照组,差异有统计学意义(t分别为3.71,2.99,8.42,4.25,2.12,3.23;P分别为0.000 5,0.004 3,0.01,0.01,0.039,0.002 3)。DPT的表达水平与RA患者的年龄,ACCP,RF及血清中IFN-γ、TNF-α、IL-12的水平不相关,而与患者ESR,CRP,IL-6水平呈正相关(r分别为0.65,0.4,0.46;P分别为0.000 4,0.04,0.02)。结论RA患者外周血DPT表达水平明显升高,在RA发病及进展中发挥重要作用。     

白血病患儿外周血T细胞亚群检测的临床意义

本研究观察急性白血病患儿外周血T细胞在不同病程阶段的变化,了解白血病患儿的免疫状况。应用流式细胞术检测42例急性白血病患儿,另选取50例正常儿童（对照组）外周血CD4^＋、CD8^＋、CD4^＋/CD8^＋比值、CD3^＋以及NK细胞在不同病程阶段的动态变化。结果表明：急性淋巴细胞白血病（ALL）与急性髓系白血病（AML）初诊患儿的CD3^＋,CD4^＋、CD8^＋细胞比例和CD4^＋/CD8^＋比值均值显著低于对照组（P〈0.05）,初诊时急性白血病患儿的NK细胞值显著低于对照组（P〈0.05）;ALL与AML患儿完全缓解期（CR）3、6和12个月时的NK细胞水平虽然缓慢上升,但与对照组比较仍具有统计学差异（P〈0.05）。结论：急性白血病患儿在病情发生以及治疗过程中细胞免疫功能存在紊乱,经治疗获CR后患儿病情好转,细胞免疫渐渐恢复,但恢复速率慢,该结果为患儿后续使用免疫调节剂治疗提供依据。     

慢性粒细胞白血病树突状细胞对特异性抗白血病T细胞的作用

树突状细胞（ＤＣ）是有效的抗原呈递细胞,我们从初诊慢性粒细胞白血病慢性期（ＣＭＬＣＰ）患者的外周血中培养出ＤＣ,探讨其对特异性抗白血病Ｔ细胞（ＡｎｔｉＬＢＴ）的作用。病例和方法１　病例　初诊ＣＭＬＣＰ患者１６例。均有ｔ（９;２２）染色体异常。其中男１０例,女６例。年龄３２（１８～４５）岁。分别将与其中６例患者ＨＬＡ相合的６名健康亲属作为正常对照。２　单个核细胞（ＭＮＣ）的分离制备　取肝素抗凝的外周血或骨髓２～３ｍｌ,按文献［１］分离外周血单个核细胞（ＰＢＭＮＣ）或骨髓单个核细胞（ＢＭＭＮ…     

肿瘤细胞裂解物致敏树突状细胞对小鼠乳腺癌作用的研究

目的观察肿瘤细胞裂解物致敏树突状细胞 (DC)对小鼠乳腺癌的治疗作用。方法无菌取小鼠骨髓细胞 ,在体外培养条件下经细胞因子作用诱导为树突状细胞 (DC) ,用EMT6肿瘤抗原裂解物冲击致敏DC细胞 ,检测DC体外刺激活化淋巴细胞作用 ,以及经DC免疫产生的细胞毒T淋巴细胞 (CTL)体外杀伤肿瘤细胞的活性 ,观察致敏DC免疫对小鼠乳腺癌模型的治疗作用。结果镜下可见抗原致敏后的DC可吸引淋巴细胞聚集成团 ;致敏DC诱导生成的特异性CTL在体外对肿瘤细胞可产生杀伤作用 (与PBS对照组比较 ,P =0 .0 2 7) ,而未成熟DC细胞组和肿瘤抗原组与PBS对照组间无显著性差异 (P =0 .17,P =0 .0 72 ) ;经致敏DC注射免疫后 ,小鼠负荷肿瘤得到抑制 (与PBS对照组比较 ,P =0 .0 3 5 ) ,而单纯肿瘤抗原及未致敏DC免疫组与PBS对照组间无显著性差异 (P =0 .2 6,P =0 .11)。结论肿瘤抗原裂解物致敏的DC可有效递呈抗原并诱导淋巴细胞杀伤肿瘤细胞。     

抗原负载对树突状细胞激发T细胞功能的影响

目的 研究抗原负载对树突状细胞（ＤＣ）表型及功能的影响。方法 将外周血单个核细胞来源的ＤＣ在体外进行肿瘤抗原的负载,再用这种ＤＣ激发自体的Ｔ细胞,通过对ＤＣ分泌白细胞介素１２（ＩＬ－１２）的测定和对Ｔ细胞表型 的分析和功能的鉴定,与未负载抗原的ＤＣ进行比较。结果 ＤＣ经过抗原负载后,其表型没有明显改变,但其分泌的ＩＬ－１２含量明显增加?而且其激发的细胞多为ＣＤ４＾＋Ｔ细胞,这种ＣＤ４＾＋Ｔ细胞本射     

Intrathymic presentation of circulating non-MHC antigens by medullary dendritic cells. An antigen-dependent microenvironment for T cell differentiation

We present evidence for intrathymic presentation of soluble circulating antigens in vivo. Our results show that proteins of different molecular weight enter the mouse thymus rapidly after i.v. injection. The intrathymic presence of antigen was assayed by proliferation of cloned antigen-specific T helper cells, which were cocultured with purified thymic stromal cells; stromal cells were isolated and purified as lymphostromal cell complexes, which preexist in vivo. Antigen presentation copurified with non-adherent medullary dendritic cells (DC) (interdigitating cells). I-A- cortical macrophages forming thymocyte rosettes in vivo and I-A+ cortical epithelial cells forming thymic nurse cells (TNC) in vivo did not act as antigen presenting cells (APC) after antigen pulsing in vivo or in vitro. Thymic APC turn over physiologically and are rapidly replaced (within 2-5 wk) after lethal irradiation by donor bone marrow-derived cells. The frequency of thymocyte-DC interactions in vivo strictly correlates with thymic T cell differentiation, and is independent of the immune status of the animal. Fetal thymic APC seem to be secluded from antigen in the maternal circulation. Thymic DC-ROS probably represent the microenvironment where maturing T cells first encounter non-MHC antigens in the context of self-MHC antigens.     

Presentation of exogenous protein antigens by dendritic cells to T cell clones. Intact protein is presented best by immature, epidermal Langerhans cells

The capacity of dendritic cells to present protein antigens has been studied with two MHC class II-restricted, myoglobin-specific, T cell clones. Spleen dendritic cells and cultured epidermal Langerhans cells (LC) presented native myoglobin weakly and often not at all. These same populations were powerful stimulators of allogeneic T cells in the primary MLR. Freshly isolated LC were in contrast very active in presenting proteins to T cell clones but were weak stimulators of the MLR. Both fresh and cultured LC could present specific peptide fragments of myoglobin to the clones. These results suggest that dendritic cells in nonlymphoid tissues like skin can act as sentinels for presenting antigens in situ, their accessory function developing in two phases. First antigens are captured and appropriately presented. Further handling of antigen then is downregulated while the cells acquire strong sensitizing activity for the growth and function of resting T lymphocytes. The potent MLR stimulating activity of cultured epidermal LC and lymphoid dendritic cells probably reflects prior handling of antigens leading to the formation of allogeneic MHC-peptide complexes.     

T cell killing by tolerogenic dendritic cells protects mice from allergy

It is well established that allergy development can be prevented by repeated low-dose exposure to contact allergens. Exactly which immune mechanisms are responsible for this so-called low zone tolerance (LZT) is not clear, although CD8⁺ suppressor T cells are known to have a role. Here, we show that TNF released by tolerogenic CD11⁺CD8⁺ DCs located in skin-draining lymph nodes is required and sufficient for development of tolerance to contact allergens in mice. DC-derived TNF protected mice from contact allergy by inducing apoptosis in allergen-specific effector CD8⁺ T cells via TNF receptor 2 but did not contribute to the generation and function of the regulatory T cells associated with LZT. The TNF-mediated killing mechanism was induced in an allergen-specific manner. Activation of tolerogenic DCs by LZT CD8⁺ suppressor T cells and enhanced TNF receptor 2 expression on contact allergen–specific CD8⁺ effector T cells were required for LZT. Our findings may explain how tolerance protects from allergic diseases, which could allow for the development of new strategies for allergy prevention.     

慢性粒细胞白血病树突状细胞瘤苗对T淋巴细胞刺激作用的研究

目的　观察细胞因子联合培养诱生的白血病树突状细胞 (DC)表型和抗原提呈功能。方法　慢性粒细胞白血病细胞和K5 6 2细胞应用GM CSF IL 4 TNF α联合培养后进行细胞表型和激活淋巴细胞对白血病细胞杀伤活性的检测。结果　CML DC和K 5 6 2 DC具有DC的形态特征和超微结构 ,表达CD1a、CD80和CD86等DC相关抗原 ,并可激活淋巴细胞产生增殖反应 ,并产生针对白血病细胞的特异性细胞毒性 ,同时此种DC可不同程度地分泌IL 12并协助淋巴细胞产生IFN γ。结论　慢性粒细胞白血病细胞和K5 6 2细胞在细胞因子的诱导下 ,可分化为具有DC形态和功能的特异性抗原提呈细胞。     

端粒酶活性对人表皮干细胞分化影响的实验研究

目的：通过重建端粒酶活性延长人表皮干细胞寿命，为组织工程皮肤修复提供理想种子细胞。方法：用差速黏附法分离获得人表皮干细胞（human epithemal stem cells，hESCs），以TRAPeze ELISA法分别检测新鲜的不同传代次数的hESCs端粒酶活性（RTA），同时把含外源性人端粒酶逆转录酶的质粒导入hESCs，比较转染细胞与非转染细胞体外培养时端粒酶活性及生存情况。结果：非转染细胞随传代次数的增多RTA逐渐减弱，到12-16PD时出现细胞衰老、死亡、增殖停止；转染细胞到26PD时细胞形态无明显改变，细胞继续生长，RTA仍未减弱。结论：人表皮干细胞在体外培养过程中，仍具有端粒酶活性，但不足以抑制该细胞的衰老。重建端粒酶活性可延长人表皮干细胞寿命并维持自我更新，为建立组织工程标准细胞系提供了新的实验手段。     

树突状细胞诱导T细胞异常与特发性血小板减少性紫癜

树突状细胞(DC)是体内最重要的抗原递呈细胞,在其诱导初始型T细胞(Th0)产生特异性免疫应答过程中可引起T细胞异常,从而引起自身免疫性疾病的发生。特发性血小板减少性紫癜正是由于该过程异常而发生的。     

Feedback control of regulatory T cell homeostasis by dendritic cells in vivo

CD4⁺CD25⁺Foxp3⁺ natural regulatory T cells (T reg cells) maintain self-tolerance and suppress autoimmune diseases such as type 1 diabetes and inflammatory bowel disease (IBD). In addition to their effects on T cells, T reg cells are essential for maintaining normal numbers of dendritic cells (DCs): when T reg cells are depleted, there is a compensatory Flt3-dependent increase in DCs. However, little is known about how T reg cell homeostasis is maintained in vivo. We demonstrate the existence of a feedback regulatory loop between DCs and T reg cells. We find that loss of DCs leads to a loss of T reg cells, and that the remaining T reg cells exhibit decreased Foxp3 expression. The DC-dependent loss in T reg cells leads to an increase in the number of T cells producing inflammatory cytokines, such as interferon γ and interleukin 17. Conversely, increasing the number of DCs leads to increased T reg cell division and accumulation by a mechanism that requires major histocompatibility complex II expression on DCs. The increase in T reg cells induced by DC expansion is sufficient to prevent type 1 autoimmune diabetes and IBD, which suggests that interference with this feedback loop will create new opportunities for immune-based therapies.CD4⁺CD25⁺Foxp3⁺ natural regulatory T cells (T reg cells) are essential for maintaining self-tolerance (Kim et al., 2007; Sakaguchi et al., 2008). The loss of these cells leads to a fatal autoimmune syndrome affecting multiple organs (Sakaguchi et al., 1995; Kronenberg and Rudensky, 2005). In addition, these cells interfere with the development of organ-specific autoimmune diseases, such as type 1 diabetes (Salomon et al., 2000; Tarbell et al., 2004; You et al., 2008) and inflammatory bowel disease (IBD), by silencing self-reactive Th1 and Th17 cells (Powrie et al., 1993; Izcue et al., 2006; Korn et al., 2007).Several requirements for T reg cell homeostasis in vivo have been defined. For example, T reg cells are IL-2 dependent and maintained by constant homeostatic division in response to self-antigens (Fisson et al., 2003; von Boehmer, 2003; Setoguchi et al., 2005). In addition to self-antigen recognition, which is essential for their activation and function (Thornton and Shevach, 1998; Samy et al., 2005), T reg cell survival in the periphery also requires co-stimulation through the CD28 and B7 pathway (Salomon et al., 2000). Finally, actively dividing T reg cells appear to be more suppressive than those that are quiescent (Klein et al., 2003). However, it is not known whether antigen-presenting cells (and which ones, if any) are required for maintaining T reg cells in vivo in the steady state (Denning et al., 2007; Yamazaki et al., 2008).DCs are specialized antigen-presenting cells that capture, process, and present antigens to T cells (Banchereau and Steinman, 1998). The outcome of the encounter between these two cell types depends on the activation status of the DC. In the steady state, antigen presentation by DCs leads to tolerance by T cell deletion, induction of anergy, or expansion of antigen-specific T reg cells (Brocker et al., 1997; Hawiger et al., 2001; Steinman and Nussenzweig, 2002; Hawiger et al., 2004; Kretschmer et al., 2005; Luckashenak et al., 2008; Yamazaki et al., 2008). In contrast, antigen presentation by DCs that are activated or matured by Toll-like receptor ligands, CD40 ligation, Fc receptor signaling, or inflammatory cytokines leads to protective T cell immunity (Steinman and Nussenzweig, 2002). Given the importance of DCs for immune activation, it might be expected that the loss of these cells would lead to the absence of immune responses. However, congenital DC deficiency leads instead to a complex generalized lympho- and myeloproliferative syndrome with some features of autoimmune disease, including increased numbers of granulocytes, inflammatory mediators, and possibly T reg cells (Birnberg et al., 2008; Ohnmacht et al., 2009). Additional clues that DCs are involved in T reg cell homeostasis are given in the recent report that Flt3 ligand (FL) can expand T reg cells (Swee et al., 2009), and that loss of T reg cells increases DC division by a FL-dependent mechanism (Liu et al., 2009). Whether these effects on DCs result in direct or indirect feedback changes in T reg cell homeostasis in vivo is not known (Birnberg et al., 2008). In this report, we examined whether DCs are required to maintain T reg cells in vivo and uncovered the existence of a feedback regulatory loop required to maintain physiological numbers of the two cell types in the steady state.     

CD1-mediated gamma/delta T cell maturation of dendritic cells

The vascular endothelial growth factor (VEGF) receptor fetal liver kinase 1 (flk1; VEGFR-2, KDR) is an endothelial cell-specific receptor tyrosine kinase that mediates physiological and pathological angiogenesis. We hypothesized that an active immunotherapy approach targeting flk1 may inhibit tumor angiogenesis and metastasis. To test this hypothesis, we first evaluated whether immune responses to flk1 could be elicited in mice by immunization with dendritic cells pulsed with a soluble flk1 protein (DC-flk1). This immunization generated flk1-specific neutralizing antibody and CD8+ cytotoxic T cell responses, breaking tolerance to self-flk1 antigen. Tumor-induced angiogenesis was suppressed in immunized mice as measured in an alginate bead assay. Development of pulmonary metastases was strongly inhibited in DC-flk1-immunized mice challenged with B16 melanoma or Lewis lung carcinoma cells. DC-flk1 immunization also significantly prolonged the survival of mice challenged with Lewis lung tumors. Thus, an active immunization strategy that targets an angiogenesis-related antigen on endothelium can inhibit angiogenesis and may be a useful approach for treating angiogenesis-related diseases.