正常人外周血中效应记忆性Th9细胞表型及与其它Th亚群之间的关系

目的探讨正常人外周血中IL-9分泌细胞的表型及Th9细胞与其他Th细胞亚群的关系。方法分离正常人外周血单个核细胞(PBMCs),在不同的刺激条件下,使用ELISA及ELISpot检测IL-9的产生情况,使用流式细胞术(FACS)分析CD3、CD4细胞中IL-9、IL-4、IFN-γ的表达情况。结果正常人外周血PBMCs在不同的刺激条件下均有IL-9的产生,在anti-CD3、anti-CD3+anti-CD28及PMA+Ionomycin的刺激下IL-9的水平分别为(21.73±10.08)pg/ml、(74.14±11.76)pg/ml、(94.76±15.36)pg/ml,各组之间差异具有统计学意义(P0.05)。外周血中CD3-IL-9+及CD3+IL-9+细胞的频率分别为0.17%±0.05%和0.70%±0.23%。在CD3+IL-9+T细胞中,Th9细胞的比例为0.51%±0.22%。正常人外周血中Th9细胞表型以效应记忆性为主(CD45RO+CD62L+CCR7-),且比例与Th2细胞呈正相关,相关系数R=0.63。结论正常人外周血中存在的IL-9分泌细胞以效应记忆性Th9细胞为主,且其比例与Th2细胞呈正相关。     

人肠道正常粘膜组织与外周血中记忆性IL-22~+T淋巴细胞频率及表型的比较

目的比较人肠道正常粘膜组织与外周血中IL-22+T淋巴细胞的频率及其表型特征。方法分离人肠道正常粘膜与外周血中单个核细胞,anti-CD3+anti-CD28刺激后,采用流式细胞术(FACS)检测IL-22的产生及其与IFN-γ、IL-17的关系,分析IL-22+T淋巴细胞CD45RO,CD62L,CCR7,CCR6,CCR10,CCR4等表面分子的表达。结果与anti-CD3+anti-CD28刺激外周血中CD4+和CD8+T淋巴细胞产生少量的IL-22(0.6%;0.57%)相比,肠道粘膜CD4+T细胞产生大约3.15%的IL-22,CD8+T淋巴细胞产生4%左右的IL-22。此外,肠道粘膜CD4+和CD8+T细胞中存在一群产生IL-22并独立于Th1、Th17,Tc1、Tc17的细胞亚群。肠道粘膜IL-22+T细胞表达较高比例的CD45RO,其中部分细胞表达CCR7,而较少表达CD62L。进一步研究表明,肠道粘膜CD4+IL-22+和CD8+IL-22+T细胞表达较高水平的CCR10(55.3%;73.9%),部分细胞表达CCR6或CCR4。结论人肠道正常粘膜组织中IL-22主要由效应型或中央型记忆T细胞产生,部分IL-22+T细胞独立于Th1、Th17,Tc1、Tc17细胞亚群。     

脐血多能干细胞对阿尔茨海默病患者外周血淋巴细胞的免疫调节作用

目的研究脐血多能干细胞(CB-SCs)对阿尔茨海默病(AD)患者外周血淋巴细胞(LCs)的调节作用,初步探讨其治疗AD的潜能。方法人脐血中分离并培养CB-SCs;AD患者外周血中分离淋巴细胞;将两者共培养3 d,其中植物凝集素P(PHA-P)刺激组刺激淋巴细胞增殖;ELISA法检测上清液中IL-1、IL-4和IL-10的含量,流式细胞仪检测淋巴细胞亚群中CD4+/CD8+T细胞的比例、CD4+T细胞中调节性T细胞的比例及Treg细胞功能蛋白IL-10和TGF-β1的阳性率。结果 1)CB-SCs能抑制PHA-P诱导的LCs增殖及LCs聚集;2)CB-SCs共培养组的促炎因子IL-1明显下降(P0.05),抗炎因子IL-4和IL-10明显上升(P0.01);3)CB-SCs可下调CD4+/CD8+T淋巴细胞比例(P0.01);4)在无PHA-P作用时CB-SCs可以增加CD4+T淋巴细胞中Treg细胞的比例(P0.01),PHA-P存在时CB-SCs主要增强Treg细胞功能蛋白的表达。结论 CB-SCs在体外对AD患者外周血的淋巴细胞具有免疫调节作用,主要通过增加Treg细胞的比例及增强其抗炎功能来发挥作用。     

急性HIV感染者外周血T淋巴细胞CD57抗原动态表达及临床意义分析

目的 研究CD57在HIV急性感染者外周血T淋巴细胞的动态表达情况及临床意义.方法 随机选取2006年11月-2009年12月期间确诊为HIV-1急性感染的17位患者为研究对象,15例健康体检者为对照组,收集HIV感染者1、3、6个月时间点及对照组外周血单个核细胞(PBMC),以流式细胞仪双色、三色分析法分别分析CD3+ CD57+T淋巴细胞、CD3+ CD4+ CD57+T淋巴细胞、CD3+CD8+CD57+T淋巴细胞的比例,并分析其与病毒载量、CD4+T细胞计数间的相关性.结果 在感染1、3、6个月外周血淋巴细胞中,CD57+T淋巴细胞比例分别为15.24％±1.49％、13.51％±2.45％及14.65％ ±1.83％,正常对照组CD57+T淋巴细胞比例为3.72％±0.56％,HIV感染1、3、6个月CD57+T淋巴细胞比例较正常对照组明显增高,差异有统计学意义(P均＜0.0001).在感染的1个月、3个月外周血中CD8+CD57+在淋巴细胞中的比例分别为7.79％ +2.10％、9.88％±2.36％,与对应时间点的病毒载量成正相关关系,R2分别为0.3700、0.3768,P值分别为0.0096、0.0088;与对应时间点CD4+T细胞计数成负相关关系,R2分别为0.3768、0.4235,P值分别为0.0215、0.0017.急性HIV感染1个月时间点,6例病情快速进展患者与11例病情非快速进展患者,CD8+ CD57+T细胞比例分别为11.20％±2.21％、6.16％±1.09％,CD4+ CD57+T淋巴细胞比例分别为2.79％ ±0.31％、1.40％±0.30％,病情快速进展患者CD8+CD57+T、CD4+CD57+T淋巴细胞比例均高于病情非快速进展组,P值分别为0.0338、0.0106.结论 HIV感染急性期CD57+T淋巴细胞比例增加,其中CD8+ CD57+T淋巴细胞百分比可反映HIV病毒载量变化及CD4+T淋巴细胞的计数情况,HIV急性感染早期CD57在淋巴细胞高表达提示病情进展迅速.     

AIDS患者γδ T 细胞能够杀伤自体HIV感染和未感染的CD4 T细胞

 目的：建立自体人类免疫缺陷病毒 (Human Immunodeficiency Virus, HIV) 感染的CD4 T细胞模型,检测获得性免疫缺陷综合症 (Acquired Immunodeficiency Syndrome, AIDS) 患者γδ T 细胞对自体HIV感染和未感染的CD4 T细胞的杀伤作用。方法：分离健康志愿者和未治疗的AIDS患者外周血单个核细胞 (PBMCs),磁珠分选获得高纯度的CD4 T细胞,加入植物血凝素（Phytohemagglutinin, PHA）和白细胞介素-2 (interleukin-2, IL-2) 共同培养,建立自体HIV感染的CD4 T细胞模型。流式细胞术检测HIV-p24+ CD4 T细胞的比例。乳酸脱氢酶 (Lactate dehydrogenase, LDH)法测定γδ T 细胞的细胞毒作用。结果：培养到第10 d时,HIV-p24+CD4 T细胞的比例达到最高值。AIDS患者的γδ T 细胞能够杀伤自体HIV感染和未感染的CD4 T细胞（细胞溶解率分别为71.1 ± 9.7和24.2 ± 18.2）。而健康志愿者γδ T 细胞对自体的CD4 T细胞没有杀伤作用（细胞溶解率为4.3 ± 10.1）。结论：AIDS患者γδ T 细胞能够杀伤自体HIV感染的CD4 T细胞,为采用γδ T 细胞过继免疫治疗AIDS提供了依据。     

老年抑郁症伴焦虑患者外周血中Th17细胞与细胞因子的改变

探讨老年抑郁症伴焦虑患者(≥60岁)外周血中Th17细胞发挥的作用。选取28例老年抑郁症伴焦虑患者为实验组,另选取老年健康体检者(≥60岁)28例为对照组。采用流式细胞术检测两组人群外周血中CD3~+、CD4~+ T淋巴细胞亚群及Th17细胞(CD4~+IL-17~+)的比例,ELISA检测患者血清中IL-6、TNF-α、IL-1β、IL-17含量,实时定量PCR检测外周血淋巴细胞中核转录因子IL-17、RORγt表达水平。老年抑郁症伴焦虑患者外周血CD3~+、CD4~+ T淋巴细胞百分率低于对照组(P均0.01),Th17细胞表达比例为(2.05±0.47)%,明显高于对照组(0.69±0.25)%,差异有统计学意义(P0.01);IL-6、TNF-α、IL-1β、IL-17在老年抑郁症伴焦虑患者组的浓度均高于对照组,差异有统计学意义(均为P0.01),老年抑郁症伴焦虑患者外周血淋巴细胞中IL-17、RORγt基因表达水平均高于对照组,差异有统计学意义(均为P0.01)。Thl7细胞与老年抑郁症伴焦虑具有相关性,可能通过分泌以IL-17为主的细胞因子造成患者机体免疫功能紊乱,参与老年抑郁症伴焦虑病情发展。     

IL-15对异基因抗原刺激下人CD8+T 细胞增殖分化影响的初步研究

目的：探讨IL-15对异基因抗原刺激下人CD8+T细胞增殖分化的影响。方法：在IL-15存在的条件下,将从健康志愿者外周血中新鲜分离的CD8+T细胞与HLA-A,-B,-DR完全错配的异体抗原提呈细胞（APCs）进行混合淋巴细胞培养（MLRs）。经9 d培养后,对诱导后产生的CD28-CD8+和CD28+CD8+T细胞亚群进行细胞毒功能测定和表型检测,并对CD8+T细胞增殖分化过程中CD28分子的动态变化规律进行监测。结果：在IL-15诱导及异基因抗原刺激下,CD8+T细胞增殖分化后产生的CD28+CD8+T细胞具有细胞毒作用,与外周血新鲜分离的类似细胞相比,其高表达了FasL、颗粒霉素-B和穿孔素;而CD28-CD8+抑制性T细胞不具有细胞毒作用,与外周血新鲜分离的类似细胞相比,低表达了FasL、颗粒霉素-B和穿孔素。在异基因抗原提呈细胞刺激下,IL-15可诱导CD8+T细胞增殖分化过程中CD28-/CD28+细胞数比例升高（从0.24到1.01）,并可诱导CD28+T细胞上的CD28分子丢失。结论：IL-15通过调节CD28分子的表达影响异基因抗原对CD8+T细胞的增殖分化。     

肺结核患者外周血CD4~+和CD8~+记忆性T细胞亚群、IL-17、IL-27表达的初步探讨

目的:探讨肺结核患者外周血CD4+和CD8+记忆性T细胞亚群及白细胞介素17(Interleukin-17,IL-17),IL-27的表达。方法:采用流式细胞术检测肺结核患者组外周血CD4+和CD8+记忆性T细胞,患者组按治疗史分为初治组,复治组;按痰涂片抗酸染色分为痰涂阳性组,痰涂阴性组。初治组8例为凡既往未用过抗结核药物治疗或用药时间少于一个月的新发病例;复治组22例为凡既往应用抗结核药物一个月以上的新发病例、复发病例、初治治疗失败病例等;痰涂阳组9例为痰涂片抗酸染色阳性;痰涂阴组21例为痰涂片抗酸染色阴性。ELISA法检测IL-17,IL-27。结果:①与健康对照组比较:患者组CD4+效应型记忆性T细胞均显著增高(P<0.05),初治组与涂阴组CD8+效应型记忆性T细胞均显著降低(P<0.05),复治组IL-17显著降低(P<0.05),而IL-27显著增高(P<0.05)。②与初治组比较:复治组CD4+中央型记忆性T细胞显著降低(P<0.05),而CD8+效应型记忆性T细胞显著增高(P<0.05),IL-17显著降低(P<0.05),IL-27显著增高(P<0.05)。③与涂阴组比较:涂阳组CD4+中央型记忆性T细胞显著降低(P<0.05),CD8+效应型记忆性T细胞显著增高(P<0.05),CD8+中央型记忆性T细胞显著降低(P<0.05)。④Spearman相关性分析显示:IL-17与IL-27呈正相关(P<0.05),记忆性T细胞亚群与IL-17,IL-27水平无显著相关性(P>0.05)。结论:肺结核患者外周血CD4+效应型记忆性T细胞的表达可望作为TB初步诊断的观察指标,CD4+中央型记忆性T细胞和CD8+效应型记忆性T细胞的表达均可望作为TB患者的临床分组依据,TB外周血IL-17、IL-27水平可望用于判断TB的炎症程度。     

IL-21在不同乙型肝炎病毒感染者外周血CD4~+T细胞中表达的初步研究

目的:探讨乙肝病毒感染不同临床表现患者外周血CD4+T细胞中IL-21表达的差异及其在发病机制中的作用。方法:分离乙肝病毒感染不同临床表现患者及健康人外周血单个核细胞(PBMC),使用PMA+ionomycin进行刺激,同时每份标本未加PMA+ionomycin刺激做阴性对照,流式细胞术(FCM)检测IL-21的表达情况及其与Th17细胞亚群的关系。结果:PMA+ionomycin刺激能够诱导IL-21的产生,产生IL-21的主要为CD4+T细胞,IL-17A+IL-21+CD4+T细胞几乎检测不到,IL-21+CD4+T细胞比例在急性乙型肝炎组、乙肝病毒携带组中较正常对照组和慢重肝组有所升高,Th17细胞亚群比例在各组中没有统计学差异;除急性乙型肝炎组外,其余各组中IL-21+CD4+T细胞比例与Th17细胞亚群比例均有较好的相关性。结论:IL-21在HBV感染不同临床表现患者外周血CD4+T的表达有一定差异,并且其与Th17细胞亚群有相关性,提示IL-21在HBV感染的发病机制可能发挥一定作用。     

1型糖尿病患者外周血IL-35表达及其对Th9细胞的调控作用

目的观察1型糖尿病(type 1 diabetes mellitus, T1DM)患者外周血IL-35的表达及其对Th9细胞的调控作用。方法入组31例T1DM患者和13例对照者, 分离血浆和外周血单个核细胞(peripheral blood mononuclear cells, PBMCs)。ELISA检测血浆IL-35和IL-9水平, 实时定量PCR法检测PBMCs中IL-35亚基EBI3和IL-12p35亚基以及Th9转录因子PU.1 mRNA相对表达量, 流式细胞术检测PBMCs中Th9细胞比例。使用重组人IL-35刺激T1DM患者和对照者PBMCs, CCK-8法检测细胞增殖, 并检测Th9细胞比例、PU.1 mRNA相对表达量、IL-9分泌水平的变化。分选11例T1DM患者PBMCs中的CD4+CCR4-CCR6-CXCR3-细胞和CD8+T细胞, 使用重组人IL-35刺激CD4+CCR4-CCR6-CXCR3-细胞, 将104个CD4+CCR4-CCR6-CXCR3-细胞与105个CD8+T细胞共培养, ELISA法检测培养上清中IFN-γ和TNF-α水平, 酶联免疫斑点试...     

Selective activation of resting human γδ T lymphocytes by interleukin-2

In rheumatoid arthritis and other inflammatory diseases we and others have found that γδ T cells express activation antigens, suggesting that they are involved in the pathogenesis of these disorders. In this study we have stimulated peripheral blood mononuclear cells from normal donors with recombinant interleukin-2 (rIL-2) to see whether such a stimulus alone could activate γδ T cells. Short-term exposure (24-96 h) to rIL-2 selectively stimulated the γδ but not the αβ T cells to express activation antigens (CD69, CD25 and HLA-DR). Long-term culture (2 weeks) in rIL-2-containing medium caused a selective increase in the proportion of the γδ T cells and a corresponding reduction of the fraction of αβ T cells. Limiting dilution analysis revealed that approximately 1/60 of the γδ T cells responded to IL-2 in contrast to only 1/250 of the αβ T cells. Comparison of the expression of the IL-2 receptor (IL-2R) a and P chains showed that there was a similar expression of the α chain on γδ and αβ T cells whereas the relative density of the β chain was more than twice as high on γδ T cells. Both the IL-2-induced proliferation of γδ T cells and the expression of activation antigens on these cells could be inhibited by an anti-IL-2Rβ monoclonal antibody (mAb) but not by an anti-IL-2Rα mAb. Expression of CD69 on γδ T cells was dependent neither on the presence of B cells, monocytes, nor αβ T cells. Finally, we found that the IL-2-induced expression of CD69 was inhibited by activation of cAMP-dependent protein kinase and by inhibition of the Src-family of the tyrosine protein kinase, but not by inhibition of protein kinase C or by activation of the CD45 associated tyrosine phosphatase. The ability of γδ T cells to be activated by IL-2 is a feature which they have in common with natural killer cells. Moreover, it may be possible that the expression of activation antigens on γδ T cells in inflammatory diseases is an epiphenomenon secondary to IL-2 produced by activated αβ T cells.     

γδ T cells are secondary participants in acute graft-versus-host reactions initiated by CD4+ αβT cells

To examine the role of T cell subpopulations in an acute graft-versus-host (GVH) reaction, γδ T cells and αβ T cells expressing one of the two prototypic Vβ gene families were negatively isolated from adult blood samples and injected into allogeneic chick embryos. CD4⁺ αβ T cells expressing either Vβ1 or Vβ2 receptors were equally capable of inducing acute GVH reactions, consistent with the idea that αβ T cell alloreactivity is determined by CDR3 variability. By themselves, the γδ T cells were incapable of inducing GVH reactions. However, host γδ T cells were recruited into the donor αβ T cell-initiated lesions, where they were activated and induced to proliferate. The data suggest that γβ T cells may play a secondary role in GVH reactions.     

Murine T Cell Determination of Pregnancy Outcome: I. Effects of Strain, αβ T Cell Receptor, γδ T Cell Receptor,and γδ T Cell Subsets

PROBLEM: T cells bearing αβ T cell receptor (TcR) and γδ TcR are present at the fetomaternal interface, and the latter, which express surface activation markers, can react with fetal trophoblast cell antigens. What is the role of these cells? METHOD: Using stress-abortion-prone DBA/2-mated CBA/J and abortion-resistant C57/B16 mice, αβ, γδ, and CD8^+/- T cell subsets were measured in spleen and uterine decidua. The effect of immunization against abortion and administration of anti-TcR antibody in vivo was examined. Cytokine synthesis was measured by intracellular staining of Brefeldin A-treated cells. RESULTS: Abortion-prone matings showed an unexpected accumulation of γδ T cells beginning in the peri-implantation period and this was suppressed by immunization against abortion. The immunization deleted γδ T cells producing the abortogenic cytokines, TNF-α and γ-interferon, and increased production of the anti-abortive cytokines, IL-10 and transforming growth factor-β2 (TGF-β2). Immunization also boosted the number of αβ T cells which were present in the decidua as early as 2 days after implantation. In vivo injection of GL4 (anti-δ) depleted γδ T cells producing Th1 cytokines in the peri-implantation period, and prevented abortions, whereas H57 (anti-β) decreased the number of αβ T cells and led to 100% abortions. CD8⁺ T cells present in peri-implant decidua before onset of abortions were mostly αβ TcR⁺, although some were γδ⁺. Changes in γδ and αβ T cells in pregnancy were most dramatic in uterine tissue. CONCLUSION: Although decidual γδ T cells after formation of a distinct placenta and fetus produce anti-abortive TGF-β2-like molecules and IL-10, prior events can lead to abortion. High local production of TNF-α and γ-interferon develop during the peri-implantation phase because of an excessive increase in the Th1 cytokine⁺ subset of γδ cells; these cytokines may be contributed by other tissues in decidua, and the contribution of bioactive factors by γδ T cells may augment the cytokine pool. In contrast, αβ T cells (which may be inactivated by stress that causes abortions) may mediate the anti-abortive effect of alloimmunization. Alloimmunization involves a shift from a Th1 to a Th2 pattern in the γδ T cells in decidua.     

Patterns of lymphokine secretion amongst mouse γδ T cell clones

Although the patterns of lymphokine (LK) secretion by CD4 and CD8 αβ T cells have been extensively studied, the question of whether γδ T cells display patterns of restricted LK production and whether these patterns are the same as seen in conventional αδ T cells has not been previously addressed. In this study we generated panels of γδ T cell clones from normal C57BL/6 and BALB/c mice using a lectin-driven system and compared their patterns of secretion of nine LK with those of CD4 and CD8 αβ T cell clones generated in the same system. The results showed that γδ T cell clones displayed nonrandom patterns of highly restricted LK production with a strong bias towards the production of type 1 LK. The dominant pattern was one of high level secretion of interferon-γ and tumor necrosis factor (TNF), with variable production of interleukin (IL)-2, and little or none of the type 2 LK IL-4, IL-5, IL-6, and IL-10. This pattern differed significantly from that of CD4 Th1 clones in that γδ clones showed a striking deficiency in the production of IL-3 and granulocyte/macrophage colony-stimulating factor. A small subset of γδ clones displayed a novel pattern, in which the only LK produced in substantial quantity were TNF and variable amounts of IL-2. The bias of γδ T cells towards type 1 LK production was not an artefact associated with cloning because bulk populations of splenic γδ T cells behaved in the same way, even when activated in the presence of high concentrations of IL-4.     

Comparative analysis of αβ and γδ T cell activation by Mycobacterium tuberculosis and isopentenyl pyrophosphate

Phosphorylated nonpeptide compounds have recently been identified as potent mycobacteria-derived ligands for human Vγ9/Vδ2-expressing γδ T cells. Crude mycobacterial extracts also contain protein antigens which stimulate CD4 αβ T cells to produce growth factors that are used by γδ T cells for clonal expansion. We have investigated the dynamics in vitro of expansion of CD4 T cells and Vγ9 cells in cultures of peripheral blood mononuclear cells stimulated with synthetic isopentenyl pyrophosphate (IPP) in the absence or presence of additional stimuli. The results indicated that following stimulation with IPP, γδ T cells express CD25 and CD69 antigens, but fail to proliferate unless growth factors are provided exogenously or endogenously through activation of CD4 T cells by additional stimuli such as tetanus toxoid, alloantigen, or superantigens. Furthermore, the presence of antigen presenting cells are required for expansion of γδ T cells. In response to IPP stimulation, purified CD4 T cells neither express CD25 or CD69, nor do they proliferate even in the presence of exogenous IL-2. Apart from IL-2, IL-15 and, less efficiently, IL-4, IL-7, and IL-12 can contribute to cellular expansion of IPP-reactive Vγ9 cells. Together, the results demonstrate that peripheral blood γδ T cells proliferate in response to IPP only if CD4 T cells are simultaneously activated by an additional stimulus. This mechanism provides a tight control of the reactivity of γδ T cells towards phosphorylated nonpeptide antigens.     

CD4(+) T cell clones producing both interferon-gamma and interleukin-10 predominate in bronchoalveolar lavages of active pulmonary tuberculosis patients.

The pattern of cytokine production in T cell clones derived from bronchoalveolar lavages (BAL) of active pulmonary tuberculosis (TB) patients was analyzed in clones obtained by limiting dilution procedures which expand with high efficiency either total T lymphocytes, independently of their antigen-recognition specificity, or Mycobacterium tuberculosis-specific T cells. BAL-derived clones, representative of CD4(+) cells from five patients with active TB, produced significantly higher amounts of IFN-gamma than BAL-derived CD4(+) clones from three inactive TB donors or four controls (with unrelated, noninfectious pathology). Average IL-4 and IL-10 production did not differ significantly in the three groups. Although these data suggest a predominant Th1 response to M. tuberculosis infection in the lungs, the majority of BAL-derived CD4(+) clones produced both IFN-gamma and IL-10 and the percentage of clones with this pattern of cytokine production was significantly higher in clones derived from BAL of active TB patients than from controls. Only rare clones derived from peripheral blood (PB)-derived CD45RO(+) CD4(+) T cells of both patients (nine cases) and controls (four cases) produced both IFN-gamma and IL-10; instead, the IL-10-producing clones derived from PB T cells most often also produced IL-4, displaying a typical Th2 phenotype. Higher average amounts of IFN-gamma and IL-10 were produced by BAL-derived CD8(+) clones of four active TB patients than of four controls, although the frequency of CD8(+) clones producing both IFN-gamma and IL-10 was lower than that of CD4(+) clones. The M. tuberculosis-specific BAL-derived T cell clones from three active TB patients were almost exclusively CD4(+) and produced consistently high levels of IFN-gamma often in association with IL-10, but very rarely with IL-4. Unlike the BAL-derived clones, the M. tuberculosis-specific clones derived from PB CD45RO(+) CD4(+) T cells of three different active TB patients and two healthy donors showed large individual variability in cytokine production as well as in the proportion of CD4(+), CD8(+), or TCR gamma/delta(+) clones. These results indicate the predominance of CD4(+) T cells producing both the proinflammatory cytokine IFN-gamma and the anti-inflammatory cytokine IL-10 in BAL of patients with active TB.     

CCL25 induces α₄β₇ integrin-dependent migration of IL-17⁺ γδ T lymphocytes during an allergic reaction

Herein, we provide evidence that during allergic inflammation, CCL25 induces the selective migration of IL-17(+) γδ T cells mediated by α(4) β(7) integrin. Intrapleural injection of CCL25 into ovalbumin (OVA)-immunized C57BL/6 mice triggered the accumulation of γδ T lymphocytes expressing CCR9 (CCL25 receptor) and α(4) β(7) integrin in the pleura, but failed to attract αβ T lymphocytes. CCL25 attracted CCR6(+) γδ T cells producing IL-17 (but not IFN-γ or IL-4). OVA challenge triggered increased production of CCL25 followed by the accumulation of CCR9(+) , α(4) β(7) (+) , and CCR6(+) /IL-17(+) γδ T cells into the pleural cavities of OVA-immunized mice, which was inhibited by the in vivo neutralization of CCL25. The in vivo blockade of α(4) β(7) integrin also inhibited the migration of IL-17(+) γδ T lymphocytes (but not of αβ T lymphocytes) into mouse pleura after OVA challenge, suggesting that the CCL25/α(4) β(7) integrin pathway is selective for γδ T cells. In addition, α(4) β(7) integrin blockade impaired the in vitro transmigration of γδ T cells across endothelium (which expresses α(4) β(7) ligands VCAM-1 and MadCAM-1), which was induced by CCL25 and by cell-free pleural washes recovered from OVA-challenged mice. Our results reveal that during an allergic reaction, CCL25 drives IL-17(+) γδ T-cell mobilization to inflamed tissue via α(4) β(7) integrin and modulates IL-17 levels.     

Expression and regulation of adhesion molecules by γδ T cells from lymphoid tissues and intestinal epithelium

T cells bearing the γδ T cell receptor localize largely in epithelial tissues, but are also present at low frequency in organized secondary lymphoid organs. To assess the role of cell surface adhesion molecules in the traffic and tissue localization of γδ T cells, we compared the expression of these molecules on both αβ and γδ T cells in several lymphoid and non-lymphoid organs. In the gut epithelium, γδ cells express less LFA-1 (CD11a), Pgp-1 (CD44), and α4 integrin than the corresponding αβ cells. In lymph nodes (LN) and Peyer's patches (PP), adhesion molecule expression by γδ cells is heterogeneous, with some of the cells having a phenotype similar to that of intraepithelial γδ cells and the rest expressing high levels of CD44 and L-selectin (CD62L) but lower β7 and α_{M 290}, a phenotype more like lymph node αβ cells. Therefore, the particular set of adhesion molecules expressed by a T cell is dependent, in part, on its anatomic location. Superimposed upon this, however, are differences in expression that are based on the type of T cell; LN and PP γδ T cells express less CD44 but much more β7, α_{M 290} and ICAM-1 (CD54) than αβ T cells in the same organ. The differences in adhesion molecules between αβ and γδ cells are not due simply to differences in their activation status, because these molecules are regulated differently after activation through the T cell receptor (TcR)/CD3 complex. The differential expression of adhesion molecules on cells bearing a particular TcR V region suggests that distinct adhesion phenotypes may arise from prior contact with specific antigen and resultant cell activation in vivo. Lastly, the presence of high level expression of α4β7 and α_{M 290} on L-selectin^lo γδ cells in lymph nodes suggests that these γδ cells may be uniquely capable of migrating to the gut. The differences in adhesion molecule expression and regulation between γδ and αβ T cells could explain, in part, the distinct homing and tissue localization of these T cell subsets in vivo.