耐受性CD8~+ NKT细胞体外增殖能力的鉴定

目的:利用CFSE标记细胞,流式细胞术(FCM)检测法,解析超抗原SEB活化的耐受性CD8+ NKT细胞在体外增殖的情况。方法:利用CFSE标记新鲜分离的C57BL/J鼠脾细胞,分别与ConA和LPS共同培养3d,收集细胞进行荧光染色并用FCM解析细胞表面CD69分子的表达率和增殖能力。CFSE标记的鼠脾细胞与SEB共培养5d和10d后,荧光染色并用FCM解析细胞表面CD69的百分数和增殖能力。SEB活化的第10天细胞经CFSE标记后在IL-2的协同作用下继续培养10d,荧光染色,FCM解析这群细胞的增殖能力、活性分子CD69的表达率和NKT细胞亚群的变化情况。结果:ConA、LPS和SEB三者均可以刺激小鼠脾细胞增殖。ConA和LPS在3d内可以使细胞增殖3代,且CD69的表达率为74.19%和41.56%;SEB在5d和10d内分别可以使细胞增殖5代和7代,细胞表面CD69的表达率为32.09%和48.66%。SEB活化的10d细胞可以在IL-2的协同下继续传代培养10d,可以增殖7代;这群细胞中CD8+ NKT细胞亚群,由原始的0.36%增加到38.58%;细胞表面CD69分子由正常值的0.11%提高到83.74%。结论:超抗原SEB活化的CD8+ NKT细胞可以在体外进行增殖培养,且这些细胞是活性化的细胞。利用CFSE标记细胞,FCM可以检测耐受性CD8+ NKT细胞在体外的增殖水平。     

哮喘患儿外周血CD3~+TCRvα24~+NKT细胞亚群分析

目的比较支气管哮喘急性发作期患儿和正常小儿外周血CD3+TCRvα24+NKT细胞频率;CD4+、CD8+、CD4-CD8-(DN)3个亚群比例;各亚群细胞胞内IL-4、IFN-γ水平及其表面活化分子CD69的表达情况。探讨NKT细胞在哮喘发作过程中的作用和机制。方法收集12例哮喘急性发作期患儿和10例健康小儿外周血,分离其中单个核细胞(PBMCs),对其表面分子CD3、TCRvα24、CD4、CD8、CD69及胞内分子IL-4、IFN-γ进行染色,流式细胞仪分析检测。结果哮喘患儿和健康小儿外周血CD3+TCRvα24+NKT细胞频率分别为0.42%、0.32%。哮喘组CD4+、CD8+、DN 3个亚群比例分别为:71.60%、14.90%、12.55%,正常对照组为:63.00%、13.12%、22.78%。哮喘患儿较正常小儿外周血CD4+NKT细胞比例上升,而DN NKT比例下降。3个亚群的NKT细胞均检测到了CD69、IL-4和IFN-γ的表达。总体而言,CD4+亚群和DN亚群胞内IL-4、IFN-γ水平较CD8+亚群高,DN NKT表面CD69表达高于其它2个亚群。但各亚群CD3+TCRvα24+NKT细胞CD69、IL-4和IFN-γ水平在哮喘组及正常对照组中未检测出明显差异。结论哮喘患儿急性发作期外周血CD3+TCRvα24+NKT细胞CD4+亚群频率上升,DN亚群频率下降。NKT细胞亚群比例的改变可能参与或介导了哮喘患儿急性期气道炎症反应。     

淋巴瘤患者外周血TCRVα24+Vβ11+自然杀伤T细胞体外活化特性研究

目的:研究淋巴瘤患者外周血TCRVα24 Vβ11 自然杀伤T(NKT)细胞的数量以及体外活化后的功能状态,与正常人外周血NKT细胞的数量及功能状态进行比较.方法:制备30例淋巴瘤患者和30例年龄及性别匹配的正常对照外周血单个核细胞(PBMNCs),以流式细胞术(FACS)检测TCRVα24 Vβ11 NKT细胞数量,以α-半乳糖神经酰胺(α-Galcer)及白细胞介素-2(IL-2)从PBMNCs中扩增活化NKT细胞,采用细胞内细胞因子流式细胞术检测手段,测定NKT细胞中胞内白细胞介素-4(IL-4)、干扰素-γ(IFN-γ)、肿瘤坏死因子-α(TNF-α)阳性细胞的比例.结果:淋巴瘤患者与正常对照PBMNCs中TCRVα24 Vβ11 NKT细胞的细胞比率分别为0.17%±0.10%、0.28%±0.18%(P<0.05).PBMNCs培养体系中加入α-Galcer及IL-2,将NKT细胞扩增活化7d后.淋巴瘤患者与正常对照的NKT细胞的扩增倍数分别为101.37±44.61、129.66±56.31(P<0.05).扩增活化后,淋巴瘤患者与正常对照的NKT细胞中胞内细胞因子IFN-γ阳性细胞的比例分别为41.96%±15.06%、52.48%±18.85%(P<0.05);TNF-α阳性细胞的比例分别为46.30%±16.03%、71.37%±17.28%(P<0.05);IL-4阳性细胞的比例分别为36.19%±11.74%、33.12%±12.95%(P>0.05).不同病理分型及分期的淋巴瘤患者之间上述各指标无显著差异.结论:淋巴瘤患者外周血TCRVα24 Vβ11 NKT细胞数量较正常对照明显减少,经α-Galcer扩增活化后扩增倍数较正常对照降低,分泌细胞因子IFN-γ、TNF-α的功能较正常降低,此数量及功能的降低与淋巴瘤的分型及分期无关.但其仍保持有对α-Galcer刺激后的扩增活化反应能力.     

正常人外周血TCRVα24+ NKT细胞体外活化特性观察

目的:探讨正常人外周血自然杀伤T(NKT)细胞的数量以及体外活化后表达CD69、IFN-γ和IL-4的规律并与CD3⁺ T细胞进行比较。方法:取正常成人外周血,直接三色荧光标记后溶血获取有核细胞,或以佛波醇酯(PDB)+离子霉素(Ion)刺激并培养6h,经三色荧光标记后溶血并获取有核细胞,以流式细胞术分析NKT细胞和T细胞的数量以及表达CD69和IL-4、IFN-γ的情况。结果:NKT细胞约占外周血T淋巴细胞总数的(1.34±0.42)%(x±s);PDB+Ion活化6h后NKT细胞CD69表达率为(96.71±1.33)%,明显高于对照组(11.47±2.86)%(P＜0.05);同样条件下CD3⁺T细胞CD69表达率分别为(98.60±0.47)%和(1.07±0.45)%(P＜0.05);当莫能菌素(monensin)存在时以PDB+Ion刺激6h后,IL-4阳性NKT细胞的百分比为48.62±2.44,明显高于对照组31.57±3.31(P＜0.05);IFN-γ阳性NKT细胞百分比为46.65±11.91,也高于对照组13.45±6.29(P＜0.01)。CD3⁺T细胞在刺激后表达IL-4和IFN-γ均明显升高,但IL-4表达率远远低于NKT细胞;而且对照组CD3⁺T细胞两种细胞因子表达率都明显低于NKT细胞。结论:正常成人外周血含有少量的NKT细胞,这些细胞IL-4和IFN-γ的表达率明显高于CD3⁺T细胞,是特定微环境里的重要免疫调节细胞。     

小鼠CD4~+ CD25~+ Foxp3~+调节性T细胞体外扩增

目的:本研究旨在探讨CD4+CD25+Foxp3+调节性T细胞体外扩增的方法。方法:采用磁珠分选小鼠CD4+T细胞,αCD3单克隆抗体包被24孔板,加入αCD28单克隆抗体、雷帕霉素、rhIL-2,培养3周后,流式细胞仪测定培养细胞中CD4+CD25+T细胞的含量,实时定量PCR检测CD4+CD25+T细胞Foxp3 mRNA的表达;单向混合淋巴细胞反应和增殖抑制试验测定扩增的CD4+CD25+T细胞的增殖及其抑制功能;ELISA检测培养上清中IL-10和TGF-β1的含量。结果:小鼠CD4+T细胞培养3周后,CD4+CD25+T细胞达(76.05±2.73)%,高于未加雷帕霉素组(52.17±1.36)%(P<0.001),磁珠分选的CD4+CD25+T细胞Foxp3 mRNA的表达是未加雷帕霉素组的5倍(P<0.001),增殖能力是未加雷帕霉素组的0.29倍(P<0.001),对CD4+T细胞增殖抑制能力是未加雷帕霉素组的3.6倍(P<0.001),培养上清中IL-10和TGF-β1分别是对照组的1.8倍和1.6倍(P<0.001)。结论:小鼠CD4+T细胞在含有1μg/ml的αCD28、rhIL-2 100 U/ml和终浓度为10 nmol/L雷帕霉素的培养体系中培养3周后能有效扩增CD4+CD25+Foxp3+调节性T细胞。     

卡介苗刺激后CD8~+T细胞活化、增殖及其调节

目的:探讨卡介苗(BCG)刺激后,结核菌素试验阳性(PPD+)正常人外周血单个核细胞(PBMCs)中CD8+T细胞的活化、增殖、细胞因子产生及调节性T细胞(Treg)对其调节作用。方法:体外用BCG刺激PPD+正常人PBMCs,检测CD8+T细胞的细胞因子产生、活化和增殖。纯化后获得调节性T细胞(Treg)和CD25-细胞,检测Treg对CD8+T细胞增殖的调节作用。结果:BCG诱导CD8+T细胞表达CD69和CD25等活化分子。在低剂量IL-2存在的条件下,BCG诱导CD8+T细胞发生增殖,且增殖的CD8+T细胞大部分表达Granzyme-B。体外BCG短期刺激PBMCs后,CD8+T细胞几乎不产生IFN-γ、IL-2和TNF-α。此外,调节性T细胞抑制CD8+T细胞增殖。结论:BCG诱导CD8+T细胞活化、增殖和表达颗粒酶,Treg抑制CD8+T细胞增殖。     

人外周血单个核细胞来源CD4~+CD25~+调节性T细胞的体外扩增培养及功能研究

目的建立人外周血单个核细胞来源的CD4+CD25+调节性T细胞体外扩增培养方法 ,研究体外扩增后细胞功能改变。方法 Ficoll-Paque密度梯度分离健康人外周血单个核细胞,免疫磁珠纯化CD4+T细胞,流式分选CD4+CD25+调节性T细胞。用抗人CD3/CD28单抗和IL-2联合刺激CD4+CD25+调节性T细胞,检测其Foxp3、IL-10和TGF-β表达改变。结果人外周血单个核细胞分离纯化得到纯度98%的CD4+CD25+调节性T细胞,Foxp3表达率为95%;使用IL-2加抗CD3/CD28单抗刺激6周后细胞数量可扩增1 000倍;扩增后细胞Foxp3的表达和IL-10、TGF-β的分泌均显著降低。结论本研究成功建立了高纯度大量CD4+CD25+调节性T细胞纯化和体外扩增方法,研究了CD4+CD25+T细胞体外扩增后功能表型的改变。     

固相MICA协同s4-1BBL、IL-15体外高效扩增CD3~+CD56~+细胞的研究

目的:观察固相MHCⅠ类相关抗原A(iMICA)是否协同s4-1BBL、IL-15促进外周血CD3+CD56+细胞的增殖并增强其活性。方法:首先将iMICA联合s4-1BBL、IL-15分别刺激外周血单个核细胞或纯化的CD3+CD56+细胞,共培养19天,动态观察CD3+CD56+细胞频率变化及记录其增殖曲线;其次利用LDH释放法和ELISA分别检测长期培养的CD3+CD56+细胞杀伤活性及IFNγ-、IL-4的分泌;最后检测CD3+CD56+细胞表面活性相关受体的表达。结果:iMICA联合s4-1BBL、IL-15促进CD3+CD56+细胞的频率自2%升高至21.7%,绝对细胞数平均增长32倍;扩增后的CD3+CD56+细胞杀伤K562活性明显增高,IFNγ-分泌能力增强,不分泌IL-4;其表面活化性受体表达上调,抑制性受体表达下调。结论:iMICA联合s4-1BBL、IL-15能高效扩增CD3+CD56+细胞,体外大量增殖后可用于肿瘤的过继免疫治疗。     

CD3~+CD56~+NKT细胞与Vα24~+iNKT细胞的检测及其表型特点分析

为了比较CD3+CD56+NKT细胞与CD3+TCRVα24+iNKT细胞在外周血淋巴细胞中的相对比例及其表面分子表达的差别,本研究采集了健康人外周全血,用四色荧光抗体染色和流式细胞术检测CD3+CD56+NKT细胞和CD3+TCRVα24+iNKT细胞在淋巴细胞中的比例,及其亚群表型及活化分子CD69的表达情况。检测结果表明,在正常人外周血淋巴细胞中CD3+CD56+NKT细胞所占比例为3.90%±2.89%,以CD8亚群占多数(57.61%±17.35%);而CD3+TCRVα24+iNKT细胞所占比例仅为0.39%±0.19%,且以CD4亚群占多数(56.60%±19.66%)。两种NKT细胞的相对数量之间存在显著正相关(r=0.467,P<0.05),但两类细胞之间极少重叠。CD16和CD161在CD3+CD56+NKT细胞上的表达量显著高于在CD3+TCRVα24+iNKT细胞上的表达量(P均<0.01)。活化分子CD69在两种细胞上的表达量均较低(P>0.05)。本研究结果表明,正常人外周血CD3+CD56+NKT细胞与CD3+TCRVα24+iNKT细胞在相对数量、亚群及表型上存在显著差异,是两种截然不同的NKT细胞。     

淋巴瘤患者外周血TCRVα24+Vβ11+自然杀伤T细胞体外活化特性研究

目的： 研究淋巴瘤患者外周血TCRVα24+Vβ11+自然杀伤T（NKT）细胞的数量以及体外活化后的功能状态，与正常人外周血NKT细胞的数量及功能状态进行比较。方法: 制备30例淋巴瘤患者和30例年龄及性别匹配的正常对照外周血单个核细胞（PBMNCs），以流式细胞术（FACS）检测TCRVα24+Vβ11+NKT细胞数量，以α-半乳糖神经酰胺（α-Galcer）及白细胞介素-2（IL-2）从PBMNCs中扩增活化NKT细胞，采用细胞内细胞因子流式细胞术检测手段，测定NKT细胞中胞内白细胞介素-4（IL-4）、干扰素-γ（IFN-γ）、肿瘤坏死因子-α（TNF-α）阳性细胞的比例。结果: 淋巴瘤患者与正常对照PBMNCs中TCRVα24+Vβ11+NKT细胞的细胞比率分别为0.17%±0.10%、0.28%±0.18%(P<0.05)。PBMNCs培养体系中加入α-Galcer及IL-2，将NKT细胞扩增活化7d后，淋巴瘤患者与正常对照的NKT细胞的扩增倍数分别为101.37±44.61、129.66±56.31(P<0.05)。扩增活化后，淋巴瘤患者与正常对照的NKT细胞中胞内细胞因子IFN-γ阳性细胞的比例分别为41.96%±15.06%、52.48%±18.85%(P<0.05)；TNF-α阳性细胞的比例分别为46.30%±16.03%、71.37%±17.28%(P<0.05)；IL-4阳性细胞的比例分别为36.19%±11.74%、33.12%±12.95%(P>0.05)。不同病理分型及分期的淋巴瘤患者之间上述各指标无显著差异。结论: 淋巴瘤患者外周血TCRVα24+Vβ11+NKT细胞数量较正常对照明显减少，经α-Galcer扩增活化后扩增倍数较正常对照降低，分泌细胞因子IFN-γ、TNF-α的功能较正常降低，此数量及功能的降低与淋巴瘤的分型及分期无关。但其仍保持有对α-Galcer刺激后的扩增活化反应能力。     

Lower proportion of CD19+IL-10+ and CD19+CD24+CD27+ but not CD1d+CD5+CD19+CD24+CD27+ IL-10+ B cells in children with autoimmune thyroid diseases

Abstract

Introduction: As it is generally known, regulatory B cells (Bregs) control inflammation and autoimmunity. The significance of Bregs in the population of children with autoimmune thyroid diseases (AITD) still offers plenty of potential to explore. The aim of this study was to estimate the expression of Bregs (phenotype CD19⁺CD24⁺CD27⁺IL-10⁺, CD19⁺IL-10⁺, CD1d⁺CD5⁺CD19⁺IL-10⁺ and CD1d⁺CD5⁺CD19⁺CD24⁺CD27⁺) in a paediatric cohort with AITD and in health controls.

Materials and methods: A total of 100 blood samples were obtained from 53 paediatric patients with Graves’ disease (GD) (N?=?12 newly diagnosed, mean age 12.5?±?3.5 and N?=?17 during methimazole therapy, mean age 12.7?±?4.4), Hashimoto’s thyroiditis (HT) (N?=?10 newly diagnosed, mean age 13.3?±?2.9 and N?=?10 during L-thyroxine therapy, mean age 13.7?±?3.4) and compared with healthy controls (C) (N?=?15, mean age 13.1?±?3.1). The expressions of the immune cell populations were analysed by four-color flow cytometry using a FASC Canto II cytometer (BD Biosciences).

Results: There was a decreasing tendency in the number of lymphocytes B producing IL-10 (B10) cells among all B lymphocytes and more widely, also among all lymphocytes, in each study group, as compared to C. We reported a reduction in IL-10 production in Bregs with the expression of CD19⁺CD24⁺CD27⁺IL-10 and CD1d⁺CD5⁺CD19⁺IL-10⁺ in both untreated and treated AITD.

Conclusions: Our data demonstrate that the reduction in the number of Bregs with CD19⁺CD24⁺CD27⁺IL-10⁺ and CD19⁺IL-10⁺ expression could be responsible for breaking immune tolerance and for AITD development in children.     

Circulating CD3+ CD4+ CD+ T lymphocytes in multiple sclerosis

Triple-antibody flow cytometry was used to search for distinctive populations of peripheral blood lymphocyte immunophenotypes in multiple sclerosis (MS). Using monoclonal antibodies to the cell surface markers CD3, CD4, and CD8, T cell subsets were quantified on a cohort of 31 MS patients (not treated with corticosteroids for at least 6 months), 30 healthy donors, and 14 patients with other autoimmune diseases (also corticosteroid treatment-free for at least 6 months). Untreated MS patients displayed a significantly greater population of CD3+CD4+CD8+ circulating T cells than healthy donors (P = 0.023). Patients with other autoimmune diseases displayed mean populations of CD3+CD4+CD8+ cells greater than normal donors and less than MS, but not significantly different from either. An additional 45 MS patients who had received corticosteroid therapy within the previous 6 months were phenotyped. Treatment of symptomatic MS with corticosteroids was associated with a smaller population of circulating CD3+CD4+CD8+ cells. Some MS patients have significantly greater numbers of peripheral blood T lymphocytes simultaneously expressing CD3, CD4, and CD8 surface markers than healthy donors and this population of cells may be reduced by corticosteroids treatment. This triple positive phenotype may be a manifestation of a systemic immune abnormality in MS.     

Expansion and differentiation of CD14+CD16(-) and CD14+ +CD16+ human monocyte subsets from cord blood CD34+ hematopoietic progenitors

To determine whether monocytes can be generated from CD34+ hematopoietic progenitors in large numbers, cord blood CD34+ cells were first expanded for 3-10 days in X-VIVO 10 medium supplemented with FCS, stem cell factor (SCF), thrombopoietin (TPO), and Flt-3 Ligand (Flt-3L), and then differentiated in IMDM medium supplemented with FCS, SCF, Flt-3L, IL-3 and M-CSF for 7-14 days. These two step cultures resulted in up to a 600-fold mean increase of total CD14+ cells. Using this approach, two subpopulations of monocytes were obtained: CD14+CD16(-) and CD14++CD16+ occurring at 2:1 ratio. 1.25(OH)2 Vitamin D3 added to the differentiation medium altered this ratio by decreasing proportion of CD14++CD16+ monocytes. In comparison to CD14+CD16(-), the CD14++CD16+ cells showed different morphology and an enhanced expression of CD11b, CD33, CD40, CD64, CD86, CD163, HLA-DR, and CCR5. Both subpopulations secreted TNF and IL-12p40 but little or no IL-10. CD14++CD16+ monocytes released significantly more IL-12p40, were better stimulators of MLR but showed less S. aureus phagocytosis. These subpopulations are clearly different from those present in the blood and may be novel monocyte subsets that represent different stages in monocyte differentiation with distinct biological function.     

Circulating CD4+CD25+ and CD4+CD25+ T cells in myasthenia gravis and in relation to thymectomy

Studies in experimental animal models of human autoimmune diseases have revealed that CD4⁺CD25⁺ T regulatory (Tr) cells are of thymic origin and have potentials in preventing auto‐aggressive immunity. Myasthenia gravis (MG) is the best‐characterized autoimmune disease. Changes in the thymus are found in a majority of patients with MG. Thymectomy has beneficial effects on the disease severity and course in a substantial proportion of MG patients. But the occurrence and characteristics of Tr cells have not yet been defined in MG. We determined the frequencies and properties of circulating CD4⁺CD25⁺ versus CD4⁺CD25^– cells in MG patients and healthy controls (HCs), with special focus on the effect of thymectomy on CD4⁺CD25⁺ cells. CD4⁺CD25^high cells comprise only about 2% of blood lymphocytes in both MG patients and HCs. Frequencies of CD4⁺CD25^high cells were similar in MG patients irrespective of treatment with thymectomy. CD4⁺CD25⁺ cells in both MG patients and HCs are mainly memory T cells and are activated to a greater extent than CD4⁺CD25^– cells, as reflected by high levels of CD45RO and human leucocyte antigen (HLA)‐DR‐positive cells. In both MG patients and HCs, CD4⁺CD25⁺ cells also contained a high proportion of CD95‐expressing cells as possible evidence of apoptosis‐proneness. Upon stimulation with anti‐CD3/CD28 monoclonal antibodies, CD4⁺CD25⁺ cells responded more vigorously than CD4⁺CD25^– cells in MG, irrespective of treatment with thymectomy, as well as in HCs. Although CD4⁺CD25^– cells are mainly naïve T cells, in non‐thymectomized MG patients, they are activated to a greater extent as reflected by higher expression of HLA‐DR and CD95 on the surface compared to HCs. The data thus show that there is no deficiency of CD4⁺CD25⁺ cells in MG, nor is the proportion of CD4⁺CD25⁺ cells influenced by thymectomy.     

Human CD4+CD25+ regulatory T cells

In this report, we review studies of human CD4+CD25+ regulatory T cells (T-reg). Although lagging a few years behind the discovery of these cells in the mouse, the equivalent population of CD4+CD25+ regulatory T cells has also been isolated from human peripheral blood, thymus, lymph nodes and cord blood. In general, the characteristics of this T cell subset are strikingly similar between mouse and man. In the recent explosion of research reports on human CD4+CD25+ cells, although the majority of the characteristics ascribed to these cells appear to be consistent, contrasting results have been found primarily in regards to potential involvement of TGFbeta and production of IL-10. One explanation for this variability may reside in the fact that markedly different techniques are used to isolate human CD4+CD25+ T-reg cells and thus may result in the comparison of T-reg populations that differ in cellular composition and/or activation state. Another potential explanation for differences in human T-reg function may rest on the extreme variability of the culture conditions and TCR stimuli that have been used to test the functional properties of these cells in vitro. The strength of the TCR signal provided to the culture greatly affects the functional outcome of the co-culture and can result in the difference between suppression and full activation. Surprisingly, it appears that stronger stimulation has a greater and more rapid effect on the T-resp cell than on the T-reg cell as it causes T-resp cells to quickly become resistant to suppression. Thus, the details of in vitro culture conditions may at least partially account for disparate findings in regard to the functional characterization of human CD4+CD25+ cells. Here we review the evidence regarding the identification of human CD4+CD25+ regulatory T cells and their possible mechanism(s) of function.     

Prognostic Values of CD38+CD101+PD1+CD8+ T Cells in Pancreatic Cancer

Programmed death-1 (PD-1), a key immune checkpoint molecule, has been developed as an oncotherapy target for various carcinomas. However, treatment with anti-PD-1 elicited only a minimal effect in pancreatic ductal adenocarcinoma (PDAC). Subsequent studies revealed the existence of a subset of PD-1⁺ T cells coexpressing CD38 and CD101, representing a fixed dysfunctional subpopulation that are not able to be rescued by anti-PD-1 immunotherapy. However, whether this subpopulation of PD-1 expressing CD8⁺ T cells could be useful in predicting PDAC stage or prognosing survival is unknown. In this study, we used flow cytometry and immunofluorescence assay to analyze the expression of CD38 and CD101 in 183 clinical PDAC samples, including 84 of peripheral blood and 99 of surgical tissues. High coexpression of CD38/CD101 on peripheral PD-1⁺CD8⁺ T cells or tumor-infiltrating lymphocytes (TILs) was found to be most significantly correlated with Tumor/Node/Metastasis (T/N/M) classification and clinical stage, in contrast PD-1⁺CD8⁺ T cells could not correlate with T classification. CD38/CD101 co-repression on TILs also correlated with the poor survival in these PDAC patient samples. Our data suggest that CD38/CD101 might represent a more helpful biomarker than PD-1 alone for diagnosis and prognosis of PDAC.     

CD4+CD8+ murine intestinal intraepithelial lymphocytes

We have studied a population of CD4+ intestinal intraepithelial lymphocytes using two-color flow cytometric analyses, and in highly purified fluorescent-activated cell-sorted preparations. Although CD4+ T cells present within the epithelial immune compartment comprised only approximately 10-20% of the total intestinal epithelial lymphoid cells, an unusually high proportion of those CD4+ lymphocytes expressed a CD4+CD8+ phenotype which is rarely encountered in peripheral T cells. By comparison, CD4+ lymphocytes from spleen or lymph nodes existed exclusively as single-positive T cells. Analyses of CD4 and CD8 expression on lymphocytes from Peyer's patches, the lamina propria, and IEL indicated that CD4+CD8+ lymphocytes were unique to the IEL. Using CD4+CD8+ preparations obtained by fluorescent-activated cell sorting, CD4+CD8+ epithelial T cells were found also to express CD3 and Thy-1 surface markers. This heretofore undescribed extrathymic population of double-positive T cells constitutes a unique peripheral T cell subset which may be involved in intestinal T cell maturation and development, or could represent a highly specialized effector population.     

CD4+ CD45RA+ and CD4+ CD45RO+ T cells differ in their TCR-associated signaling responses.

Peripheral CD4+ T cells can be divided into two different functional populations based on the expression of distinct isoforms of the surface molecule CD45. We have investigated the differences in the proximal signaling induced by anti-CD3 monoclonal antibody in purified populations of "naive" CD45RA+ and "memory" CD45RO+ human CD4+ T cells. Expression of cell surface CD3, CD4 and CD28 was comparable between RA+ and RO+ cells. However, TCR-directed stimulation in the form of anti-CD3 produced markedly different patterns of intracellular signaling. Greater inositol triphosphate generation occurred in naive cells and the rise in intracellular free calcium was also substantially greater in naive than in memory cells. Cells with the naive phenotype were considerably more active in TCR-dependent tyrosine phosphorylation, both at an overall level and specifically in terms of TCR-zeta and ZAP-70 phosphorylation. Despite these differences in phosphorylation, the amounts of TCR-zeta, ZAP-70 and Ick were equivalent between the two subsets. These findings suggest that the TCR-dependent signaling is differentially regulated in naive and memory CD4+ T cells. This may be due to differences in the way that the two isoforms of the CD45 phosphatase regulate the activity of proximal kinases in the TCR signaling pathway, and could be an important means by which the unique functions of differentiated T cell populations are maintained.