流产模型孕鼠脾脏调节性T细胞分离纯化方法的初步建立

目的探索流产模型孕鼠CD4＋CD25＋T细胞和CD4＋CD25-T细胞快速高效的分选方法。方法采用免疫磁珠两步法分离流产模型孕鼠脾脏中T细胞,分离后的细胞经台盼蓝染色检测细胞存活率,经流式细胞仪检测分离的纯度。结果流产模型孕鼠脾脏细胞经过免疫磁珠细胞分选法2次分选得到CD4＋/CD25＋调节性T细胞纯度为（93.5±1.1）%,CD4＋/CD25-T细胞纯度为（96.6±0.6）%。结论采用免疫磁珠细胞分选法能够快速高效的得到高纯度的CD4＋CD25＋T细胞和CD4＋CD25-T细胞。     

免疫磁珠法分离人外周血CD4+CD25+调节性T细胞

目的 建立人外周血单个核细胞中CD4 CD25 调节性T细胞(regulatery T cells,Treg)免疫磁性细胞分离力(megnetic activated cell sorting,MACS),并鉴定其分离效率.方法 采用免疫磁珠两步法(即阴性分选和阳性分选2步)分离人周血单个核细胞中的CD4 CD25 调节性T细胞,首先采用生物素标记的鸡尾酒抗体和抗生物素标记的磁珠阴性分选CIM细胞,再用抗CD25 的磁珠阳性分选CD4 CD25 T细胞.分离后的细胞经抗体染色后再通过流式细胞仪检测其分离纯度;内因子染色检测其转录因子FOXV3的表达频率;台盼蓝染色检测细胞的存活率;3H-TdR掺入法检测其对CD4 CD25-T细脆殖抑制效应.结果 阴性分选CD4 T细胞的纯度为(92.2±1.7)%,阳性分选后CD4 CD25 Treg细胞的纯度(95.1±1.2)%.胞内因子染色FOXF3在CD4 CD25 Treg细胞中的表达率为(80.4±1.2)%,台盼蓝染色细胞存活率为(95.6±3.3)%.3H-TdR掺入法检测其对CIM CD25-T细胞具有明显的抑制作用.结论 采用免疫磁性细胞分离技术能够高效、快地得到一群纯度高并且细胞活力好的CD4 CIY25 Treg,为进一步研究其功能提供了方便.     

小鼠CD4+CD25+T细胞的分离、鉴定和体外功能的检测

目的　建立CD4 CD2 5 T细胞的免疫磁性分离(MACS)方法,并检测其体外免疫抑制功能。方法　分离C5 7BL 6小鼠和Balb c小鼠脾脏细胞后运用MACS法分离CD4 CD2 5 T淋巴细胞,用台盼蓝染色法和流式细胞法检测选出细胞的活性和纯度,用淋巴细胞转化实验分析其免疫抑制功能。结果　MACS分选法分选出的CD4 CD2 5 T细胞活性>97% ,纯度>95 % ;此方法获得的CD4 CD2 5 T细胞在体外不增殖,经丝裂原活化后可以抑制同品系小鼠和异品系小鼠的CD4 CD2 5 -T细胞增殖,这种抑制作用具有剂量依赖性。结论　MACS法可简单迅速分选出高纯度无菌CD4 CD2 5 T细胞,且不影响细胞活力。CD4 CD2 5 T调节性细胞在体外具有免疫无能和免疫抑制作用;丝裂原活化的该细胞免疫抑制功能具有剂量依赖性,但不具有抗原特异性。     

小鼠CD4+记忆性T淋巴细胞的产生、纯化、鉴定及皮肤移植的检测

目的 建立CD4+记忆T细胞(memory T lymphocytes,Tm)的免疫磁珠分离方法,并检测其体外部分功能.方法 借助小鼠皮肤移植模型,制备受鼠脾细胞悬液,运用免疫磁珠方法分离CD4+Tm,用台盼蓝染色法和流式细胞仪检测分选所得细胞的活性和纯度,并在体外用ELISPOT技术检测其不同抗原刺激时IFN-γ活性分泌频数.结果 小鼠皮肤移植皮片平均存活时间为(13.6±0.9)d;分离所得CD4+Tm的活细胞百分率为(98.4±0.7)%;流式细胞术检测表型,其中CD4+CD8-细胞比例占(96.06±2.49)%,CD44+CD62L-细胞比例占(94.13±2.36)%,CD4+CCR7-细胞比例占(96.39±1.93)%;在无刺激物作用或者大鼠脾细胞、供体脾细胞、刀豆素A等刺激物作用时,IFN-γ活性分泌频数分别为3±1、6±3、339±14、108±9个/104,差异有统计学意义.结论 通过小鼠皮肤移植模型及免疫磁性分离技术,可制备高纯度无菌的CD4+Tm,其细胞活力不受影响,作用具有良好的供体特异性.这为深入研究Tm在移植物免疫方面的作用提供了技术资料.     

CD3/CD28免疫磁珠法体外扩增外周血T淋巴细胞

目的探讨CD3/CD28免疫磁珠在外周血T淋巴细胞体外激活、扩增中的应用。方法 Ficoll密度梯度离心法分离健康人外周血单个核细胞、CD3免疫磁珠分选、CD3/CD28免疫磁珠激活和细胞因子扩增CD3+T细胞。流式细胞术分析CD3+T细胞纯度,台盼蓝染色分析细胞活性和细胞计数分析扩增效率。结果流式细胞术检测显示CD3+T细胞纯度达99.80%,其中CD8+T细胞占39.33%。CD3/CD28免疫磁珠激活和扩增前后细胞活性无明显变化[(97.05±2.36)%vs(96.34±2.14)%,P0.05],然而CD3+T细胞扩增可持续7~10 d,扩增倍率可达8倍,与对照组(CD3单克隆抗体包被和PBS)相比,差异有统计学意义(P0.05)。结论 CD3/CD28免疫磁珠可在体外实现CD3+T细胞的有效激活与扩增,为肿瘤过继免疫治疗提供了新方法。     

荷瘤小鼠脾脏髓源抑制细胞的分选及鉴定

目的研究荷瘤小鼠脾脏中髓源抑制细胞(myeloid derived suppresser-cell,MDSCs)的分选与鉴定方法。方法常规培养小鼠肾癌细胞(Renca细胞),于Balb/c小鼠皮下建立小鼠肾癌模型;分离小鼠脾脏制成单细胞悬液,磁珠分选Gr-1+CD11b+双阳性的MDSCs;台酚蓝染色检测细胞存活率;流式细胞仪(flow cytometry,FCM)测其细胞纯度;显微镜下观察细胞形态;免疫荧光测其表面Gr-1、CD11b荧光表达情况;RT-PCR检测Cox2和Arg-1的m RNA的表达情况;小鼠皮下成瘤实验观察MDSCs促肿瘤生长。结果成功建立小鼠肾癌模型,磁珠分选后经FCM检测Gr-1+CD11b+双阳性的MDSCs细胞可达92.3%,显著高于分选前(P0.01);免疫荧光鉴定结果显示:分选后的细胞形态完整,Gr-1和CD11b的荧光表达于细胞膜且2种荧光可以融合;RT-PCR检测分选后的MDSCs细胞群的Cox2和Arg-1的m RNA相对表达量显著高于分选前(P0.05);小鼠皮下成瘤观察到MDSCs组与实验对照组有显著差异(P0.05)。结论用免疫磁珠从荷瘤小鼠脾脏中成功分选得到MDSCs,具有较高纯度和良好的生物活性,为后续实验提供了理想的细胞来源。     

免疫磁珠分选系统在分离大鼠骨髓干细胞群中的应用

采用免疫磁珠分选系统(MACS)分离大鼠骨髓Thy-1.1 干细胞群。收集大鼠胫骨和股骨的骨髓细胞,Percoll密度梯度离心分离单个核细胞,Thy1.1单抗标记,间接MACS分离纯化Thy-1.1 干细胞群,流式细胞仪检测其纯度和分选前后CD34 百分比,台盼兰拒染法检测细胞活力,计算回收率。结果表明分选后的Thy-1.1 细胞纯度达94.2%,回收率64.7%;分选后细胞活力为99.6%,与分选前99.8%无明显差异;分选前CD34 百分比为1.2%,与分选后1.3%无差异。MACS能有效分选大鼠骨髓Thy-1.1 干细胞群,所得细胞纯度高,细胞活力保持好。大鼠Thy-1.1抗原与CD34分子无明显相关性。     

体外扩增自体CD4~+CD25~+调节性T细胞促进小鼠供体来源肿瘤的转移

目的研究输注体外扩增自体CD4+CD25+调节性T细胞(regulatory T cells,Tregs)治疗是否存在增加供体来源肿瘤转移的风险。方法取Balb/c(H-2d)小鼠骨髓细胞,在重组鼠源性GM-CSF和IL-4诱导以及TNF-α刺激下分化为成熟树突状细胞。免疫磁珠法(MACS)从Balb/c(H-2d)小鼠脾脏分选出CD4+CD25+Tregs,加入成熟树突状细胞和高浓度重组鼠源性IL-2,体外扩增7 d。流式细胞术检测新鲜以及扩增后CD4+CD25+Tregs纯度及免疫抑制功能。将Balb/c(H-2d)小鼠随机分为2组,实验组:经尾静脉注射1×107体外扩增后CD4+CD25+Tregs,24 h后注射5×105 B16-F10(H-2b)(鼠源性黑色素瘤细胞);对照组:单独输注5×105 B16-F10(H-2b)。结果新鲜分选和扩增后CD4+CD25+Tregs纯度及免疫抑制功能无明显下降。对照组肺部肿瘤结节为(9±8)个,实验组肺部肿瘤结节为(118±15)个。与对照组相比,实验组肺部肿瘤结节明显增加(P0.01)。结论体外扩增的CD4+CD25+Tregs具有抑制机体抗肿瘤能力,过继输注体外扩增的自体CD4+CD25+Tregs治疗移植后排斥反应,能够增加供体来源肿瘤转移的风险。     

Mtb-Ag活化γδT细胞的扩增及对γδT细胞CD69分子表达的影响

目的 用结核杆菌低分子多肽抗原(Mtb-Ag)激活和扩增γδT细胞,观察γδT细胞表面CD69分子表达的情况.方法 分离获取健康人外周血单个核细胞(PBMC),用Mtb-Ag刺激PBMC,所得细胞用磁珠阳性分选,通过荧光单抗TCR γδPE染色及流式细胞仪检测γδT细胞所占比例.用γδPE/CD69FITC细胞双染检测初次刺激和再次刺激γδT细胞CD69分子的表达情况.结果 新鲜分离的PBMC中γδT细胞的比例仅为(4.9±1.85)％,Mtb-Ag刺激培养10d后升为(69.2±6.57)％,免疫磁珠阳性分选后达(99.3±8.92)％.Mtb-Ag初次刺激γδT细胞,CD69分子的表达24 h达高峰,为75.2％;Mtb-Ag再次刺激γδT细胞,CD69分子的表达6h达高峰,为72％.结论 Mtb-Ag能特异地刺激PBMC中的γδT细胞增殖,Mtb-Ag初次和再次刺激均可特异性活化γδT细胞.     

ConA刺激对CD4~+CD25~+调节性T细胞趋化特性及其表面趋化因子受体CCR4/CCR6表达的影响

目的体外动态观察ConA激活的调节性T细胞表面趋化因子受体的表达变化及其趋化特性,为利用调节性T细胞诱导免疫耐受提供线索。方法常规分离正常健康人外周血单个核细胞,免疫磁珠阴性分选CD4+T细胞;加FITC-An-tiCD4抗体,APC-AntiCD25抗体,PE-AntiCD127抗体上流式细胞仪分选出CD4hiCD127loCD25hi-int细胞。纯化的调节性T细胞与CD4+CD25-T分别用ConA(10μg/mL)刺激0、24、48h后,用趋化因子CCL1、CCL5、CCL20、CCL22做趋化实验,观察各趋化因子作用下调节性T细胞与CD4+CD25-T细胞的趋化特性。同时,流式细胞仪检测CCR4与CCR6的表达。结果分离得到的调节性T细胞纯度为97.4%,活细胞率为95%,得率:4.1%。CCL1、CCL20、CCL22均可趋化调节性T细胞,且在ConA激活后趋化效率随时间而改变。CCL1与CCL22对调节性T细胞的趋化指数显著高于CD4+CD25-T细胞;CCL20对调节性T细胞和CD4+CD25-T细胞趋化指数都很高;CCL5对调节性T细胞趋化性则显著弱于CD4+CD25-T细胞。ConA刺激后...     

High-avidity CD8+ T cells

The primary goal of vaccination is the establishment of protective immunity. Thus there has been significant effort put toward the identification of attributes of the immune response that are associated with optimal protection. Although the number of virus-specific cells elicited is unquestionably important, recent studies have identified an additional parameter, functional avidity, as critical in determining the efficiency of viral clearance. T-cell avidity is a measure of the sensitivity of a cell to peptide antigen. High-avidity cells are those that can recognize antigen-presenting cells (APC) bearing very low levels of peptide antigen, whereas low-avidity cells require much higher numbers of peptide major histocompatibility complex (MHC) complexes in order to become activated or exert effector function. We are only now beginning to gain insights into the molecular control of avidity and the signals required for the optimal activation, expansion, and retention of high-avidity cells in vivo. This review summarizes the current knowledge regarding CD8⁺ T-cell avidity and explores some of the important issues that are, as of yet, unresolved.     

Alloantigen-induced regulatory CD8+CD103+ T cells

Regulatory T cells (Tregs) appear of great importance in the balance between alloreactivity and tolerance and subsets of both CD4(+) and CD8(+) T cells have been recognized to function as regulatory T cells after allogenic transplantation. Among the CD8(+) T-cell subsets, the CD103(+) cells were most recently identified as regulatory. In this review, we describe their phenotypical and functional properties, as well as their relevance for the alloimmune response in vivo. These CD8(+)CD103(+) Tregs are generated within mixed lymphocyte cultures (MLCs) and are elevated by additional transforming growth factor-beta. Interestingly, myeloid dendritic cells are the responsible cell type for induction of CD103(+) Tregs. Allostimulated CD8(+)CD103(+) Tregs display an antigen-experienced effector phenotype with limited effector functions such as cytotoxicity and interferon-gamma production and show a reduced proliferation capacity after restimulation. Beside this anergic phenotype, CD8(+)CD103(+) Tregs are able to suppress alloreactive effector T cells. Through intracellular cytokine staining and transwell assays, we showed that the mechanism of suppression is cytokine independent, but close cell-cell contact is required for suppression.     

Upregulation of CD4 on CD8+ T cells: CD4dimCD8bright T cells constitute an activated phenotype of CD8+ T cells

Aside from an intermediate stage in thymic T-cell development, the expression of CD4 and CD8 is generally thought to be mutually exclusive, associated with helper or cytotoxic T-cell functions, respectively. Stimulation of CD8+ T cells, however, induces the de novo expression of CD4. We demonstrate that while superantigen (staphylococcal enterotoxin B, SEB) and anti-CD3/CD28 costimulation of purified CD8+ T cells induced the expression of CD4 on CD8+ T cells by 30 and 17%, respectively, phytohaemagglutinin (PHA) stimulation did not induce CD4 expression on purified CD8+ T cells but significantly induced the expression of both CD4 on CD8 (CD4dimCD8bright) and CD8 on CD4 (CD4brightCD8dim) T cells in unfractionated peripheral blood mononuclear cells (PBMC). The level of the PHA-mediated induction of CD4dimCD8bright and CD4brightCD8dim was at 27 and 17%, respectively. Depletion of CD4+ T cells from PBMC abrogated this PHA-mediated effect. Autologous CD4+ and CD8+ T-cell co-cultures in the presence of PHA induced this CD4dimCD8bright T-cell expression by 33%, demonstrating a role for CD4 cells in the PHA-mediated induction of the double positive cells. The induction of CD4dimCD8bright was independent of a soluble factor(s). Phenotypic analysis of CD4dimCD8bright T cells indicated significantly higher levels of CD95, CD25, CD38, CD69, CD28, and CD45RO expression than their CD8+CD4- counterparts. CD4dimCD8bright T cells were also negative for CD1a expression and were predominantly T-cell receptor (TCR) alphabeta cells. Our data demonstrate that CD4dimCD8bright T cells are an activated phenotype of CD8+ T cells and suggest that CD4 upregulation on CD8+ T cells may function as an additional marker to identify activated CD8+ T cells.     

CD8+ T cells in autoimmunity

Mounting evidence shows that CD8(+) T cells contribute to the initiation, progression and regulation of several pathogenic autoimmune responses in which these cells were not previously thought to play a major role. CD8(+) T cells can kill target cells directly, by recognizing peptide-MHC complexes on target cells, or indirectly, by secreting cytokines capable of signaling through death receptors expressed on the target cell surface. Autoreactive CD8(+) T cells can also contribute to autoimmunity by releasing cytokines capable of increasing the susceptibility of target cells to cytotoxicity, or by secreting chemokines that attract other immune cells to the site of autoimmunity. Autoreactive CD8(+) T cells can also downregulate autoimmune responses. Recent important advances include a mechanistic understanding of events leading to the activation and recruitment of autoreactive CD8(+) T cells in certain autoimmune responses and a greater appreciation of the diverse roles that these T cells play in autoimmunity.     

Generation of peptide-specific CD8+ T cells by phytohemagglutinin-stimulated antigen-mRNA-transduced CD4+ T cells

Functional analysis of antigen-specific CD8(+) T cells is important for understanding the immune response in various immunological disorders. To analyze CD8(+) T cell responses to a variety of antigens with no readily defined peptides available, we developed a system using CD4(+) phytohemagglutinin (PHA) blasts transduced with mRNA for antigen molecules. CD4(+) PHA blasts express MHC class I and II, and also CD80 and CD86 and are thus expected to serve as potent antigen presenting cells. EGFP mRNA could be transduced into and the protein expressed by more than 90% of either LCL or CD4(+) PHA blasts. Its expression stably persisted for more than 2 weeks after transduction. In experiments with HLA-A*2402 restricted CD8(+) CTL clones for either EBNA3A or a cancer-testis antigen, SAGE, mRNA-transduced lymphoid cells were appropriate target cells in ELISPOT assays or (51)Cr releasing assays. Finally, using CD4(+) PHA blasts transduced with mRNA of a cancer-testis antigen MAGE-A4, we successfully generated specific CTL clones that recognized a novel HLA-B*4002 restricted epitope, MAGE-A4(223-231). Messenger RNA-transduced CD4(+) PHA blasts are thus useful antigen presenting cells for analysis of CD8(+) T cell responses and induction of specific T cells for potential immunotherapy.     

Activated CD4+ CD25+ T cells suppress antigen-specific CD4+ and CD8+ T cells but induce a suppressive phenotype only in CD4+ T cells

CD4(+) CD25(+) regulatory T cells are increasingly recognized as central players in the regulation of immune responses. In vitro studies have mostly employed allogeneic or polyclonal responses to monitor suppression. Little is known about the ability of CD4(+) CD25(+) regulatory T cells to suppress antigen-specific immune responses in humans. It has been previously shown that CD4(+) CD25(+) regulatory T cells anergize CD4(+) T cells and turn them into suppressor T cells. In the present study we demonstrate for the first time in humans that CD4(+) CD25(+) T cells are able to inhibit the proliferation and cytokine production of antigen specific CD4(+) and CD8(+) T cells. This suppression only occurs when CD4(+) CD25(+) T cells are preactivated. Furthermore, we could demonstrate that CD4(+) T-cell clones stop secreting interferon-gamma (IFN-gamma), start to produce interleukin-10 and transforming growth factor-beta after coculture with preactivated CD4(+) CD25(+) T cells and become suppressive themselves. Surprisingly preactivated CD4(+) CD25(+) T cells affect CD8(+) T cells differently, leading to reduced proliferation and reduced production of IFN-gamma. This effect is sustained and cannot be reverted by exogenous interleukin-2. Yet CD8(+) T cells, unlike CD4(+) T cells do not start to produce immunoregulatory cytokines and do not become suppressive after coculture with CD4(+) CD25(+) T cells.     

Tolerogenic dendritic cells impede priming of naïve CD8+ T cells and deplete memory CD8+ T cells

Type 1 diabetes is a T‐cell‐mediated autoimmune disease in which autoreactive CD8⁺ T cells destroy the insulin‐producing pancreatic beta cells. Vitamin D3 and dexamethasone‐modulated dendritic cells (Combi‐DCs) loaded with islet antigens inducing islet‐specific regulatory CD4⁺ T cells may offer a tissue‐specific intervention therapy. The effect of Combi‐DCs on CD8⁺ T cells, however, remains unknown. To investigate the interaction of CD8⁺ T cells with Combi‐DCs presenting epitopes on HLA class I, naive, and memory CD8⁺ T cells were co‐cultured with DCs and proliferation and function of peptide‐specific T cells were analyzed. Antigen‐loaded Combi‐DCs were unable to prime naïve CD8⁺ T cells to proliferate, although a proportion of T cells converted to a memory phenotype. Moreover, expansion of CD8⁺ T cells that had been primed by mature monocyte‐derived DCs (moDCs) was curtailed by Combi‐DCs in co‐cultures. Combi‐DCs expanded memory T cells once, but CD8⁺ T‐cell numbers collapsed by subsequent re‐stimulation with Combi‐DCs. Our data point that (re)activation of CD8⁺ T cells by antigen‐pulsed Combi‐DCs does not promote, but rather deteriorates, CD8⁺ T‐cell immunity. Yet, Combi‐DCs pulsed with CD8⁺ T‐cell epitopes also act as targets of cytotoxicity, which is undesirable for survival of Combi‐DCs infused into patients in therapeutic immune intervention strategies.