CMVpp65基因修饰的树突状细胞刺激自身T细胞活化

巨细胞病毒（CMV）感染易发生于慢性移植物抗宿主病（cGVHD）患者，其特异性免疫依赖于T细胞活性。本研究探讨CMVpp65基因修饰的树突状细胞（DC）对自身T细胞的活化作用。采用具有高效转染非分裂细胞的慢病毒系统将CMV全长pp65基因导入鼠源性DC；采用CpG—DNA诱导DC细胞成熟；采用流式细胞术及免疫荧光方法测定T淋巴细胞抗原及IFNγ表达。结果表明：慢病毒感染DC的感染复数（multiplicity of infection，MOI）为50，最佳感染效率可达30％-40％；表达pp65基因的成熟DC能刺激自身naiveT细胞表达CD69；表达PP65蛋白的成熟DC能够刺激自身CD4^＋或CD8^＋T细胞分泌IFNγ。结论：pp65基因修饰、CpG—DNA诱导成熟的DC能体外激活CMV特异性T淋巴细胞。     

骨髓增生异常综合征骨髓单个核细胞内负调控因子的研究

为研究MDS患者细胞凋亡与骨髓内不同T细胞亚群胞内负调控因子的关系，采用胞内细胞因子染色技术对骨髓内不同亚群T细胞胞内的TNF—α和IFN-γ水平进行检测和分析，用RT—PCR技术测定BMMNC的凋亡基因Fas的mRNA水平。结果表明，MDS患者骨髓内产生TNF-α增多的淋巴细胞为CD4^ CD45RO^ 、CD8^ CD45RO^ 细胞，产生IFN-γ增多的为CD4^ CD45RO^ 、CD8^ CD45RO^ 、CD8^ CD45RA^ 细胞，但均以CD8^ CD45RO^ 细胞为主；MDS患者T淋巴细胞产生的IFN-γ与Fas mRNA存在相关性，而TNF—α与Fas mRNA相关性不强。结论：MDS患者造血微环境中不仅T淋巴细胞亚群失调，而且各亚群分泌负调控因子增多；MDS患者髓内IFN-γ主要来自于T淋巴细胞。     

淋巴细胞免疫表型质控品的初步研究

目的研究液氮冻存对外周血单个核细胞（PBMCs）CD4^＋T和CD8^＋T百分比的影响，探索冻存PBMCs作为淋巴细胞免疫表型质控品的可行性。方法收集健康成人抗凝全血，用淋巴细胞分离液分离PBMCs后液氮冻存。定期复苏PBMCs检测CD4^＋T和CD8^＋T百分比，计算细胞存活率、回收率。并分析不同厂家试剂、复苏方法、固定时间等因素对CD4^＋T和CD8^＋T百分比的影响。结果液氮冻存0～12个月、12～24个月的PBMCs CD4^＋T和CD8^＋T百分比均保持在稳定水平。冻存12个月PBMCs CD4^＋T和CD8^＋T百分比的平均变异系数（CV）分别为14．5％和9．8％，细胞存活率为85．4％～94．3％，回收率33．3％～97．8％；冻存12-24个月PBMCs的CD4^＋T和CD8^＋T百分比的平均CV值分别为7．1％和6．5％，细胞存活率为88．3％～98．5％，回收率52．3％～101％。不同复苏方法和检测试剂的结果相对稳定，CD4^＋T和CD8^＋T百分比的平均CV值分别为8．1％和6．4％。复苏后的PBMCs经多聚甲醛固定可在48h内检测。结论液氮冻存的PBMCs有望作为淋巴细胞免疫表型测定的质控品。     

类风湿关节炎患者EB病毒感染检测及Th细胞免疫学分析

目的 调查本区域内类风湿性关节炎（RA）与EB病毒感染的相互关系，并探求其免疫相关机制。方法 选取临床确诊的76例RA患者，检测其血清EB抗体（IgG／VCA）及INF-У、IL-4、IL-8、ANA和外周血中CD3^＋、CD4^＋及CD8^＋；以40例体检健康者作为对照。结果 （1）RA患者血清中IgG／VCA阳性率显著高于对照组；（2）血清中INF-У及IL-8平均含量均显著高于对照组；（3）RA患者血清中ANA阳性率高于正常对照；（4）与对照组相比，RA患者外周血中CD3^＋计数及CD4^＋／CD8^＋值降低、CD8^＋增高。以上差异均有显著性（P〈0．05）；（5）RA患者血清IL-4平均含量及外周血CD4^＋计数与对照组相比，差异无显著性（P〉0．05）。结论 EB病毒感染与RA发病可能有关，血清IgG／VCA检测可作为RA的辅助诊断指标之一；EB病毒可能致患者体内免疫调节异常，引发自身免疫的病理变化；RA患者体内存在Th1细胞与Th2细胞激活紊乱现象，并伴血清IL-8含量增高，可能与RA患者持续关节的炎性损伤有关。     

乙型肝炎病毒感染者CD8^＋T淋巴细胞T细胞抗原受体Vβ基因互补决定区3克隆化特征的研究

目的研究乙型肝炎病毒感染者CD8^＋T淋巴细胞T细胞抗原受体（TCR）Vβ基因互补决定区3（CDR3）克隆化特征。方法选用20例乙型肝炎感染者及20例同期健康体检者,应用多引物聚合酶链反应（PCR）方法同时扩增TCRVβ基因CDR3区多个片段,高分辨率琼脂糖凝胶电泳检测克隆化特征。结果乙型肝炎病毒感染者CD8^＋T细胞TCR Vβ9和Vβ14克隆化明显高于正常对照组,分别为70．0％vs 25．0％、85．0％vs 30．0％（P〈0．01）。结论乙型肝炎病毒感染者存在CD8^＋T细胞TCR Vβ9和Vβ14克隆性变化。     

急性髓系白血病患者T淋巴细胞内细胞因子表达特性

T淋巴细胞在抗肿瘤的免疫反应中起着重要作用，而大部分肿瘤患者往往存在免疫功能低下。本研究通过对急性髓系白血病（AML）患者T淋巴细胞胞内细胞因子特性的研究，以了解AML患者在不同状态下T淋巴细胞的功能。18例不同状态下初诊AML患者和10例健康成人外周血中的T淋巴细胞在莫能霉素存在的情况下，体外经PMA和离子霉素（ionomycin）刺激后，分别进行CD4-FITC、CD8-FITC荧光单克隆抗体染色和IFNγ-PE、IL4-PE荧光单克隆体胞内染色，最后进行流式细胞仪分析。结果表明：初诊AML患者中CD4^＋和CD8^＋T淋巴细胞胞内IFNγ分泌水平均明显低于健康成人外周血T淋巴细胞，CD4^＋和CD8^＋T细胞胞内IL-4分泌水平与成人外周血细胞无显著差异。处于临床缓解状态的AML患者，CD8^＋T淋巴细胞刺激后胞内产生IFNγ的量明显高于初诊AML患者（P〈0、05）．但与健康成人无显著差异（P〉0、05）。复发的AML患者外周血中CD4^＋T细胞和CD8^＋T细胞刺激后胞内产生IFNγ量明显低于健康成人外周血T淋巴细胞以及处于完全缓解状态的AML患者CD8^＋T淋巴细胞（P〈0、05）．而IL-4的量明显高于健康成人和初诊AML患者CD4^＋T细胞和CD8^＋T细胞（p〈0．05）。结论：处于不同状态下的AML患者T细胞亚群分泌的细胞因子发生了改变，与之相应的是，初次诊断的AML患者外周血中CD4‘和CD8’T淋巴细胞刺激后Th1／Tcl细胞反应低下，Th2／Tc2细胞反应与健康成人T淋巴细胞无差异；完全缓解状态的AML患者T细胞Thl反应虽然仍低下，但Tcl反应明显增强，与健康成人无差异；复发的AML患者CD4^＋和CD8^＋T细胞Th2／Tc2样反应较Thl／Tcl样反应明显增强。     

EB病毒相关性噬血细胞综合征患儿T淋巴细胞CD69的表达及意义

目的探讨外周血T淋巴细胞CD69表达在EB病毒相关性噬血细胞综合征（epsteinbarr virus—associated hemophagocytic syndrome，EBV—AHS）患儿中的变化及意义。方法应用流式细胞术检测EBV—AHS患儿（急性期28例，缓解期21例）及30例健康对照儿童外周血CD3^＋CD4^＋CD69^＋及CD3^＋CD8^＋CD69^＋的表达水平，对检测结果进行统计学分析。结果三组受试者间CD3^＋CD4^＋CD69^＋及CD3^＋CD8^＋CD69^＋的表达水平差异均有统计学意义（P均〈0．01）；急性期组CD3^＋CD4^＋CD69^＋及CD3^＋CD8^＋CD69^＋的表达水平明显高于缓解期组及对照组，且差异均有统计学意义（P均〈0．01）；缓解期组CD3^＋CD4^＋CD69^＋及CD3^＋CD8^＋CD69^＋的表达水平明显高于对照组，且差异均有统计学意义（P均〈0．01）。结论T淋巴细胞的过度活化在EBV—AHS发病过程中起重要作用，是EBV—AHS重要的发病机理之一。检测T淋巴细胞CD69的表达有利于临床判断治疗效果，并为应用免疫调节剂提供理论依据。     

人工抗原呈递细胞复合物体外诱导特异性T淋巴细胞活化的研究

本研究旨在以人工抗原呈递细胞（artificial antigen—presenting cells，amPfs）体外模拟树突状细胞生物学功能，探讨诱导特异性T淋巴细胞活化、增殖的作用。以磁性微珠为载体，选取慢性髓系白血病特异性抗原CML28作为目标抗原肽，通过抗原表位预测软件获取CML28表位序列（Vltfaedsv），并以该抗原表位与MHC分子（HLA—A2-Ig）偶联，作为第一信号分子，B7—1分子作为第二信号分子，将两种信号分子同时负载于磁珠表面，构建人工APC复合体；取HLA—A2^＋的健康骨髓捐赠者骨髓单个核细胞，以磁珠分选出CD8^＋T淋巴细胞并与人工APC复合体系统共培养。培养过程中加入羧基荧光素二醋酸盐琥珀酰亚胺酯（5，6-carboxylfluorescin diacetate succinimidyl ester，CFSE），并以此检测T细胞增殖，用流式细胞仪检测特异性T细胞增殖程度。结果发现：实验组中CML28一特异性T细胞增殖程度明显增高，实验组平均值为（17.34±0．35）％，对照组平均值为（2．25±0．43）％，两者比较差异显著（P〈0．01）。结论：人工APC复合体系统在体外能模拟人体抗原呈递细胞，刺激CD8^＋T特异性淋巴细胞活化、增殖。     

动员后外周血中CD34+细胞去除前后对改善肢体缺血疗效的研究

目的对动员的外周血单个核细胞（PBMNC）和动员的去除CD34^＋细胞的PBMNC移植治疗裸鼠下肢缺血的疗效进行比较，以探讨PBMNC的治疗机制。方法经过单采获得G-CSF动员的PBMNC后，一部分通过CD34磁珠抗体分选得到去除CD34^＋细胞的PBMNC。动员的PBMNC和动员的去除CD34^＋细胞的PBMNC荧光标记后按1×10^6细胞或相应体积的PBS分别局部肌肉注射移植到裸鼠缺血下肢。观察下肢血流灌注以及毛细血管密度。用ELISA法检测下肢肌肉的血管内皮生长因子（VEGF）表达，并进一步观察表达的VEGF是否由移植细胞分泌。结果PBMNC移植后缺血下肢血流明显恢复，毛细血管密度明显增加，但去除CD34^＋细胞的PBMNC移植组疗效有所下降。细胞移植后4周，PBMNC组的血流灌注由（20．3±4．2）％恢复为（96．4±5．6）％，对照组仅恢复为（71．3±4．4）％（P〈0．01），去除CD34^＋细胞组恢复为（83．8±5．2）％（P〈0．05）。PBMNC组血管密度为（521±47）／mm^2，去除CD34^＋细胞组为（3964-21）／mm^2（P〈0．05），但仍高于对照组[（276±43）／mm^2]（P〈0．05）。在PBMNC组可以观察到移植的细胞整合到缺血的毛细血管壁。缺血肌肉VEGF的表达明显升高，其共表达VEGF和移植的单个核细胞。结论移植G-CSF动员的PBMNC不但可以通过干细胞整合到血管壁的机制促进血管生长，还可以通过提供细胞因子的机制促进血管生长。去除CD34^＋细胞削弱了动员的PBMNC移植治疗肢体缺血的血管新生效应。     

致敏的脐血源树突状细胞诱导CTL特异杀伤白血病细胞的实验研究

探讨脐血单个核细胞（MNC）诱导的树突状细胞（DC）通过负载冻融的HL-60、K562细胞抗原体外诱导产生细胞毒性T淋巴细胞（CTL）对HL-60、K562的杀伤作用。取脐血12份,分离MNC。在MNC中加入细胞因子GM-CSF（granulocyte monocyte colony-stimulating factor）、IL-3（interleukin 3）、SCF（stemcell factor）和EPO培养4周。使用CD83、CD1a、CD11C和CDw123单克隆抗体、流式细胞仪测定培养前后脐血DC抗原变化及扩增情况。DC通过负载HL-60、K-562白血病细胞抗原致敏T淋巴细胞产生CTL^3H-TdR掺入试验测定DC免疫刺激活性,MTT法观察CTL对HL-60、K562细胞的特异性杀伤活性。结果表明：新鲜脐血CD1a^＋、CD11c^＋、CD83^＋、CDw123^＋细胞数分别为0．27×10^5／ml、5．87×10^5／ml、1．94×10^5／ml、2．73×10^5／ml。加入上述细胞因子培养的脐血MNC分化为CD1a^＋、CD11C^＋、CD83^＋、CDw123^＋DC,经培养2—4周,DC数明显增多,分别达11．02×10^5／ml、28．24×10^5／ml、10．57×10^5／ml、18．7×10^5／ml,此后逐渐减少。细胞因子诱导脐血DC具有免疫刺激活性,且DC与CBMNC细胞比例为1：40时的刺激活性最佳。冻融法得到的HL-60、K562白血病细胞抗原致敏DC诱导的CTL对HL-60、K562细胞的杀伤率分别为（42．04±8．46）％和（31．25±11．07）％,与实验组比较有显著性差异（P〈0．01）。结论：加入细胞因子GM—CSF、IL-3、SCF和EPO培养2-4周的脐血MNC可分化为cD1a^＋、CD11C^＋、CD83^＋、CDw123^＋DC。冻融法得到的HL-60、K562白血病细胞抗原致敏DC,其诱导的CTL对HL-60、K562细胞具有特异的杀伤作用。脐血DC作为抗原呈递细胞在肿瘤免疫治疗上将起到重要作用。     

Redirecting human CD4+ T lymphocytes to the MHC class I-restricted melanoma antigen MAGE-A1 by TCR alphabeta gene transfer requires CD8alpha

Adoptive immunotherapy involving the transfer of autologous tumor or virus-reactive T lymphocytes has demonstrated its effectiveness in the eradication of cancer and virally infected cells. Clinical trails and in vitro studies have focused on CD8+ cytotoxic T-cell receptor (TCR) alphabeta lymphocytes since these cells directly kill virally infected- and tumor cells after antigen-specific recognition via their TCR alphabeta. However, increasing evidence suggests that induction of sustained immunity against cancer and viral infections depends on the presence of tumor- or virus-specific CD4+ T lymphocytes, which are restricted by MHC class II. Here, we show that these MHC class II-restricted CD4+ T lymphocytes can efficiently be redirected to MHC class I-restricted tumor cells by retroviral introduction of an HLA-A1/MAGE-A1-specific chimeric two-chain TCR ValphaCalphazeta/VbetaCbetazeta (tcTCR/zeta). However, TCR-transduced CD4+ T lymphocytes were only able to specifically bind to HLA-A1/MAGE-A1 complexes and respond to HLA-A1+/MAGE-A1+ melanoma cells when the CD8alpha gene was cointroduced. These CD4+/CD8alpha+/TCR(POS) T lymphocytes produce IFN-gamma, TNFalpha and IL-2 when specifically stimulated via the introduced TCR with immobilized HLA-A1/MAGE-A1 complexes or HLA-A1+/MAGE-A1+ melanoma cells. Furthermore, introduction of the CD8alpha gene into TCR(POS) T lymphocytes rendered these T lymphocytes cytotoxic for HLA-A1+/MAGE-A1+ melanoma cells. These results demonstrate that human CD4+ T lymphocytes when genetically grafted with an HLA-A1/MAGE-A1-specific TCR and CD8alpha are induced to kill and produce cytokines upon specific interaction with the relevant melanoma cells. Hence, CD4+ T lymphocytes, in addition to CD8+ T lymphocytes, may be critical effector cells for adoptive immuno-gene therapy to generate a sustained tumor-specific immune response in cancer patients.     

Influenza virus-induced dendritic cell maturation is associated with the induction of strong T cell immunity to a coadministered,normally nonimmunogenic protein

We evaluated the proposal that during microbial infection, dendritic cells (DCs) undergo maturation and present a mixture of peptides derived from the microbe as well as harmless environmental antigens. Mice were exposed to an aerosol of endotoxin free ovalbumin (OVA) in the absence or presence of influenza virus. In its absence, OVA failed to induce B and T cell responses and even tolerized, but with influenza, OVA-specific antibodies and CD8+ cytolytic T lymphocytes developed. With or without infection, OVA was presented selectively in the draining mediastinal lymph nodes, as assessed by the comparable proliferation of infused, CD8+ and CD4+, TCR transgenic T cells. In the absence of influenza, these OVA-specific T cells produced little IL-2, IL-4, IL-10, and IFN-gamma, but with infection, both CD4+ and CD8+ T cells made high levels of IL-2 and IFN-gamma. The OVA plus influenza-treated mice also showed accelerated recovery to a challenge with recombinant vaccinia OVA virus. CD11c+ DCs from the mediastinal lymph nodes of infected mice selectively stimulated both OVA- and influenza-specific T cells and underwent maturation, with higher levels of MHC class II, CD80, and CD86 molecules. The relatively slow (2-3 d) kinetics of maturation correlated closely to the time at which OVA inhalation elicited specific antibodies. Therefore respiratory infection can induce DC maturation and simultaneously B and T cell immunity to an innocuous antigen inhaled concurrently.     

The generation and characterization of LMP2-specific CTLs for use as adoptive transfer from patients with relapsed EBV-positive Hodgkin disease

Cellular adoptive immunotherapy for virus-associated malignant disease is an attractive strategy, since viral antigens provide targets for specific T lymphocytes. In Epstein-Barr virus (EBV)-positive Hodgkin disease (HD), a limited number of EBV-encoded antigens such as the latent membrane antigens (LMP) 1 and 2 are expressed on the malignant Reed-Sternberg cells. The authors aimed to generate cytotoxic T lymphocytes (CTLs) from patients with relapsed HD by specifically targeting LMP2A. Patients with relapsed HD have highly immunosuppressive tumors and have been heavily pretreated with cytotoxic agents. As a result, monocytes and lymphocytes are numerically reduced and functionally impaired. Approaches using dendritic cells (DCs) as the sole antigen-presenting cell to expand LMP2-specific CTL lines in vitro have proved impractical. The authors now show how small amounts of patient peripheral blood can be used to produce DCs expressing LMP2 after Ad5F35 transduction, and how an initial reactivation of LMP2-specific CTLs can be followed by stimulation with lymphoblastoid cell lines overexpressing LMP2 from the same vector. Large numbers of LMP2-specific cytotoxic lymphocytes are produced that contain both CD4+ and CD8+ T cells (favoring long-term persistence in vivo) and recognize multiple LMP2 epitopes (minimizing the risk of tumor antigen loss variants). This approach is being used in a current clinical trial.     

FcγRIIIa (CD16) induction on human T lymphocytes and CD16pos T-lymphocyte amplification

During serial assays designed to amplify natural killer (NK) cells in vitro, we observed that when peripheral blood mononuclear cells (PBMCs) from human immunodeficiency virus positive (HIV+) patients were stimulated for 2 weeks with an Epstein-Barr virus-infected B lymphoblastic cell line and interleukin-2, a well known procedure to amplify NK cells in vitro, 44.4 ± 18% CD3CD16 T lymphocytes were recovered together with NK cells, of which 78.2% expressed an αβ T-cell receptor (TCR). To identify the T-cell compartment from which they originated (naive, antigen experienced, CD16, or CD16), we first compared the results obtained with HIV+ patients' PBMCs (where essentially all CD8 cells are antigen experienced) with those obtained from cord blood lymphocytes (essentially naive) and PBMC from healthy donors (with variable antigen experience). Two weeks after stimulation, αβ TCR CD16 T lymphocytes increased from 0.3%, 2.2%, and 8.2% to 2.5%, 7.7%, and 36.3%, for cord blood, healthy donors, and HIV+ patients, respectively. Second, using cell-sorting experiments for CD16 cells and antibody-dependent cellular cytotoxicity assays, we demonstrated that a functional CD16 receptor could also be induced at the cell surface of αβ TCR CD16 T lymphocytes. Together, these results demonstrate that under stimulation conditions known to induce NK cell proliferation, a subset of αβ TCR CD16 T cells arises from antigen-experienced CD16 cells but also from antigen-experienced CD16 T lymphocytes, revealing the possibility to increase a patient's antibody-dependent cellular cytotoxicity potential through simple stimulation of this particular memory compartment.     

Dendritic cells cultured in anti-CD40 antibody-immobilized plates elicit a highly efficient peptide-specific T-cell response

The function of dendritic cells (DCs), antigen-presenting cells that can initiate and regulate cellular and humoral responses, is highly influenced by their level of maturation. Immature DCs may be harmful in anti-tumor immunotherapy, because they can induce immunotolerance rather than immunostimulation. In this study, the authors sought to determine the optimal culture conditions for obtaining fully mature DCs. When DCs were cultured in agonistic anti-CD40 monoclonal antibody-immobilized plates, they showed a higher expression of the maturation marker CD83 than DCs cultured without CD40 ligation or those cultured in medium supplemented with anti-CD40 monoclonal antibody. In addition, when interferon-gamma (IFN-gamma) was added to the medium, additive up-regulation of CD83 expression was observed. These DCs treated with both maturation signals showed a higher secretion of interleukin-12. To evaluate the capacity of antigen presentation, specific cytotoxic T lymphocytes were generated using autologous DC pulsed with a human lymphocyte antigen-A24-restricted peptide epitope derived from carcinoembryonic antigen. Interferon-gamma-secreting CD8+ T cells were analyzed by flow cytometry using the cellular affinity matrix technology. Dendritic cells, matured with CD40 ligation and IFN-gamma, were more efficient at eliciting an antigen-specific T-cell response in vitro than DCs stimulated with anti-CD40 monoclonal antibody or IFN-gamma alone. A cytotoxicity assay using carcinoembryonic antigen-expressing tumor cell lines also showed that DCs matured with both signals were more efficient at inducing cytotoxic T lymphocytes. These results demonstrate that DC culture in an anti-CD40 monoclonal antibody-immobilized plate in medium supplemented with IFN-gamma has a positive impact on DC maturation and may be optimal for eliciting an antigen-specific T-cell response without the need for CD4+ T-helper epitopes.     

Expansion of melanoma-specific cytolytic CD8+ T cell precursors in patients with metastatic melanoma vaccinated with CD34+ progenitor-derived dendritic cells

Cancer vaccines aim at inducing (a) tumor-specific effector T cells able to reduce/eliminate the tumor mass, and (b) long-lasting tumor-specific memory T cells able to control tumor relapse. We have shown earlier, in 18 human histocompatibility leukocyte antigen (HLA)-A*0201 patients with metastatic melanoma, that vaccination with peptide-loaded CD34-dendritic cells (DCs) leads to expansion of melanoma-specific interferon gamma-producing CD8+ T cells in the blood. Here, we show in 9 out of 12 analyzed patients the expansion of cytolytic CD8+ T cell precursors specific for melanoma differentiation antigens. These precursors yield, upon single restimulation with melanoma peptide-pulsed DCs, cytotoxic T lymphocytes (CTLs) able to kill melanoma cells. Melanoma-specific CTLs can be grown in vitro and can be detected in three assays: (a) melanoma tetramer binding, (b) killing of melanoma peptide-pulsed T2 cells, and (c) killing of HLA-A*0201 melanoma cells. The cytolytic activity of expanded CTLs correlates with the frequency of melanoma tetramer binding CD8+ T cells. Thus, CD34-DC vaccines can expand melanoma-specific CTL precursors that can kill melanoma antigen-expressing targets. These results justify the design of larger follow-up studies to assess the immunological and clinical response to peptide-pulsed CD34-DC vaccines.     

硒与树突状细胞对T细胞杀伤白血病细胞活力的影响

本研究探讨经亚硒酸钠（Na2SeO3）处理、K562细胞裂解物冲击致敏的外周血衍生的树突状细胞（DC）的生物学特性和体外诱导抗原特异性细胞毒性T淋巴细胞（CTL）应答的能力。健康人外周血单个核细胞（PBMNC）于体外在含3种细胞因子（rhGM—CSF、rhIL-4、TNF-α）的RPMI1640＋10％FBS培养液中培养4天，收获贴壁细胞，实验分4组：DCⅠ组：仅含DC；DCⅡ组：DC＋Se（0．5μmol／L）；DCⅢ组：DC＋K562细胞裂解液；DCⅣ组：在DCⅢ组中加入Se（0．5μmol／L）。在培养的第7天于倒置显微镜下进行活细胞观察。用流式细胞术（FCM）检测细胞表型CD1a、CD40、CD83、CD86。乳酸脱氢酶（LDH）释放试验检测CTL效应。用酶联免疫吸附试验（ELISA）测定IL-12含量。结果表明：各组DC均具有典型树突状细胞形态，均较培养前集落增多。DCⅠ组和DCⅡ组的细胞形态及数量无明显差异，DCⅢ组和DCⅣ组的细胞集落数量增加，悬浮细胞比例增加。各组DC细胞的CD1a、CD40、CD83、CD86表达率较PBMNC明显增高（P〈0．01），各组间DC细胞的CD1a和CD40的表达率无明显差异，DCⅢ组和DCⅣ组的CD83和CD86的表达率均高于DCⅠ组和DCⅡ组（P〈0.01），DCⅠ和DCⅡ以及DCⅢ和DCⅣ两组之间CD83和CD86表达率均无明显差异。在效靶比例为25：1时，各组DC致敏的T淋巴细胞对K562细胞的杀伤率为15．3±2．3％、26．3±3．7％、28．2±4.5％和36．2±3．7％，均明显高于未经DC致敏的单独T淋巴细胞组（5．9±2．4％）（P〈0．01），DCⅣ组的CTL效应最强，高于DCⅠ、Ⅱ、Ⅲ组（P〈0．01），DCⅡ和DCⅢ组的CTL效应也高于DCⅠ组（P〈0．01），而DCⅡ和DCⅢ两组间CTL效应程度无明显差异（P〉0.05）；各组DC与T淋巴细胞共培养的上清液中IL-12水平为256．96±64．2、328．12±43.9、322．98±53．5和353.85±46．2pg／ml，均显著高于未经DC致敏的单独T淋巴细胞组（35?     

转染外源性FasL的CD34+细胞诱导同种抗原特异性T细胞凋亡的实验研究

为探讨通过Fas/FasL途径选择性去除移植物中成熟T细胞的可能性 ,本研究借助反转录病毒途径 ,以FasL基因转染骨髓CD34+ 细胞 ,与经过富集的T细胞进行单向混合培养 (刺激细胞 /效应细胞比例为 5∶1) ,加入或不加入IFN γ ,IL 2 ,应用原位末端标记法 (TUNEL)和流式细胞术 (FCM)检测培养 5天后的细胞凋亡率 ,并比较两种细胞因子对移植物中CD34+ 细胞的影响。以转染外源FasL的CD34+ 细胞为刺激细胞 ,T细胞凋亡率为 (12 .1±1.5 ) %〔对照组为 (3.2± 1.1) % ,P <0 .0 1〕 ;经IFN γ或IL 2作用后 ,转染细胞诱导T细胞的凋亡率分别上升至(2 0 .1± 2 .3) % ,(17.6± 1.3) % (P <0 .0 1) ;且IL 2对CD34+ 细胞Fas抗原的表达无明显影响。上述结果表明 ,转染外源FasL的骨髓CD34+ 细胞可诱导同种抗原特异性T细胞凋亡 ,IFN γ和IL 2增强上述致细胞凋亡作用 ,且IL 2更有利于临床应用 ;提示该方案可选择性清除移植物中同种抗原特异性T细胞 ,可望为临床上防治移植物抗宿主病 (GVHD)提供新的途径     

骨髓间充质干细胞对体外分化的原态(naive)T细胞分泌细胞因子的影响

目的观察骨髓间充质干细胞(MSC)对原态(naive)T细胞的反应,探讨其免疫调节机制。方法传代培养3代的MSC经60Co照射后与脐血CD34+细胞分化产生的原态T细胞共孵育1周,用ELISA方法检测培养上清细胞因子的变化。结果孵育7d后,与MSC共孵育后T细胞数量明显增加,为(9.15±0.68)×105/孔,而原态T细胞单独培养组为(4.87±1.33)×105/孔(P<0.05);ELISA检测共孵育组IFNγ分泌减少为(1.147±0.181)pg/ml,而原态T细胞单独培养组为(4.897±0.189)pg/ml、共孵育组IL2分泌增加为(16.141±2.729)pg/ml,而原态T细胞单独培养组为(2.551±0.460)pg/ml,未检测到IL4和IL10。结论MSC有一定的抗原性,与MSC共孵育导致原态T淋巴细胞增殖,MSC可能通过直接或间接抑制T细胞产生IFN-γ发挥免疫抑制作用。为进一步阐明MSC免疫调节机制提出新的线索。