T-bet重组腺病毒对哮喘小鼠Thl/Th2免疫平衡的调节

目的 探讨静脉应用T-bet重组腺病毒(AdT-bet)对哮喘模型小鼠过敏性气道炎症及Th1/Th2免疫失衡的影响.方法 36只C57BL/6小鼠随机分为AdT-bet治疗组(A组)、模型对照组(B组)、正常组(C组).以卵蛋白(OVA)、氢氧化铝免疫建立哮喘模型,A组激发前尾静脉注射100 μL的AdT-bet(1×108PFU/μL),各组激发后肺泡灌洗分析细胞组份,分离肺淋巴细胞测定细胞因子分泌水平,以流式细胞仪检测CD3 、CD4 T细胞比例及表达IFNγ和IL-4的比例,比较各组肺组织学改变.结果 静脉应用AdT-bet组与对照组相比:①可明显抑制抗原激发后气道内嗜酸性粒细胞的浸润(P＜0.01);②明显抑制肺淋巴细胞产生IL-4、IL-5,增加了IFNγ的产生;③肺脏淋巴细胞CD4 IFNγ 百分比及IFNγ /IL-4 明显升高(P＜0.01),而CD4 IL-4 百分比则明显下降;④明显抑制哮喘鼠气道内及肺泡内的过敏性炎症反应.结论 激发前静脉用AdT-bet对哮喘小鼠过敏性气道炎症有明显的防治作用,其机制可能与表达的T-bet上调Thl/Th2比值,从而调整了免疫平衡有关.     

T-bet重组腺病毒对哮喘小鼠Thl/Th2免疫平衡的调节

目的探讨静脉应用T-bet重组腺病毒（AdT-bet）对哮喘模型小鼠过敏性气道炎症及Th1／Th2免疫失衡的影响。方法36只C57BL/6小鼠随机分为AdT-bet治疗组（A组）、模型对照组（B组）、正常组（C组）。以卵蛋白（OVA）、氢氧化铝免疫建立哮喘模型，A组激发前尾静脉注射100μL的AdT-bet（1×10^8 PFU/μL），各组激发后肺泡灌洗分析细胞组份，分离肺淋巴细胞测定细胞因子分泌水平，以流式细胞仪检测CD3^＋、CD4^＋ T细胞比例及表达IFNγ和IL-4的比例，比较各组肺组织学改变。结果静脉应用AdT-bet组与对照组相比：①可明显抑制抗原激发后气道内嗜酸性粒细胞的浸润（P〈0．01）；②明显抑制肺淋巴细胞产生IL-4、IL-5，增加了IFNγ的产生；③肺脏淋巴细胞CD4^＋ IFNγ百分比及IFNγ^＋/IL-4^＋明显升高（P〈0．01），而CD4^＋ IL-4^＋百分比则明显下降；④明显抑制哮喘鼠气道内及肺泡内的过敏性炎症反应。结论激发前静脉用AdT-bet对哮喘小鼠过敏性气道炎症有明显的防治作用，其机制可能与表达的T-bet上调Th1／Th2比值，从而调整了免疫平衡有关。     

职业苯接触工人外周血T-bet和GATA-3表达变化的特点

目的: 了解职业苯接触及慢性苯中毒工人外周血中T细胞特异性转录因子T-bet和GATA-3 mRNA表达情况。方法: 利用SYBR Green I实时荧光定量PCR分别检测20例正常人、25例职业苯接触工人和27例慢性苯中毒工人外周血单个核细胞T-bet和GATA-3 mRNA表达情况。结果: 在职业接触苯工人组及慢性苯中毒工人组,多数样本表现为GATA-3表达上升和T-bet表达下降,而少数病人则表现为相反的模式。GATA-3在正常人的表达水平为0.39±0.22,与正常组对照比较职业接触苯工人组中有19例GATA-3表达水平呈上升趋势(0.57±0.54), 慢性苯中毒工人组中则有20例GATA-3表达水平呈上升趋势(0.52±0.50)。此外,在职业接触苯工人组中发现6例GATA-3表达水平显著下降(0.15±0.12,P<0.05), 同样在慢性苯中毒工人组中也有7例GATA-3表达水平显著下降(0.07±0.06,P<0.05)。T-bet在正常人的表达水平为2.15±1.45,与正常组对照比较职业接触苯工人组中有19例T-bet表达水平呈下降趋势(1.91±1.49), 慢性苯中毒工人组中T-bet表达水平均呈下降趋势(1.52±0.56)。此外,在职业接触苯工人组中也可发现6例T-bet表达水平显著上升(3.19±2.10,P<0.05)。结论: 职业苯接触及慢性苯中毒影响工人外周血中T细胞特异性转录因子T-bet和GATA-3 mRNA表达水平。     

树突细胞与哮喘Th1/Th2失衡

特应性哮喘患者以Th2免疫反应为主,导致气道炎症,Th1／Th2失衡是特庆性哮喘重要的免疫病理机制,树突细胞（DCs）中肺部主要抗原递呈细胞,不但可以介志对吸入抗原初始的免疫反应,活化辅助性T细胞,而且在可以决定T细胞的分化方向,维持哮喘Th2免疫反应和Th1／Th2失衡机制中发挥重要作用而日益受到重视。本文就近年来对特应性哮喘免疫病理机制中DCs对Th1／Th2失衡影响认识作一综述。     

T-bet、GATA3及相关因子的表达与胃癌及转移的相关性研究

目的：分析胃癌患者Th1和Th2两类细胞因子的基因表达与转录因子T-bet和GATA3表达的相关性,从细胞因子与转录因子角度考证胃癌患者Th1/Th2细胞分化趋势,探讨p53与T-bet的相关性,了解T-bet与肿瘤转移之间的关系。方法：利用荧光定量PCR技术检测55例胃癌患者及45例正常人外周血单个核细胞（PBMC）中T-bet、GATA3转录因子和IFN-γ、IL-4等细胞因子的水平,应用免疫组化法检测胃癌组织中p53的表达状况。结果：55例胃癌患者T-bet、GATA3、IFN-γ、IL-4的表达率依次为51%（28/55）、78%（43/55）、27%（15/55）、69%（38/55）。定量PCR结果显示,病人组的T-bet和IFN-γ明显低于正常对照组（P〈0.01）,而GATA3和IL-4则明显高于正常对照组（P〈0.01）。T-bet与IFN-γ在病人体内的mRNA表达存在正相关性（P〈0.01）,正常人则没有。GATA3与IL-4的表达在两组中均呈明显正相关（P〈0.01和P〈0.05）,且在p53阳性的患者中,T-bet的表达率较低,而GATA3的表达率较高。结论：胃癌患者有明显Th2漂移现象,且p53的表达与T-bet的表达呈负相关。     

Instruction of naive CD4+ T-cell fate to T-bet expression and T helper 1 development: roles of T-cell receptor-mediated signals

Using T-cell receptor (TCR) transgenic mice, we demonstrate that TCR stimulation of naive CD4(+) T cells induces transient T-bet expression, interleukin (IL)-12 receptor beta2 up-regulation, and GATA-3 down-regulation, which leads to T helper (Th)1 differentiation even when the cells are stimulated with peptide-loaded I-A(b)-transfected Chinese hamster ovary cells in the absence of interferon-gamma (IFN-gamma) and IL-12. Sustained IFN-gamma and IL-12 stimulation augments naive T-cell differentiation into Th1 cells. Intriguingly, a significant Th1 response is observed even when T-bet(-/-) naive CD4(+) T cells are stimulated through TCR in the absence of IFN-gamma or IL-12. Stimulation of naive CD4(+) T cells in the absence of IFN-gamma or IL-12 with altered peptide ligand, whose avidity to the TCR is lower than that of original peptide, fails to up-regulate transient T-bet expression, sustains GATA-3 expression, and induces differentiation into Th2 cells. These results support the notion that direct interaction between TCR and peptide-loaded antigen-presenting cells, even in the absence of T-bet expression and costimulatory signals, primarily determine the fate of naive CD4(+) T cells to Th1 cells.     

Cytotoxic T lymphocyte antigen 4 immunoglobulin modified dendritic cells attenuate allergic airway inflammation and hyperresponsiveness by regulating the development of T helper type 1 (Th1)/Th2 and Th2/regulatory T cell subsets in a murine model of asthma

T helper type 2 (Th2) and regulatory T cells (T(reg) ) have been postulated to have critical roles in the pathogenesis of allergic asthma. Cytotoxic T lymphocyte antigen 4 immunoglobulin (CTLA4Ig) gene-modified dendritic cells (DC-CTLA4Ig) have the potential to reduce Th2 cells and induce T(reg) cells. In the present study, we evaluated the therapeutic effects and potential mechanisms of the adoptive transfer of DC-CTLA4Ig into mice in an experimental model of asthma. BALB/c mice were sensitized with ovalbumin (OVA) and challenged with aerosolized OVA for 7 days. Just prior to the first challenge, DC-CTLA4Ig, DCs or DCs infected with DC-green fluorescent protein (GFP) were injected intravenously into mice. The administration of DC-CTLA4Ig reduced airway hyperresponsiveness, relieved asthmatic airway inflammation and decreased the numbers of esosinophils in the BALF in OVA-sensitized/challenged mice. In addition, DC-CTLA4Ig altered the balance of Th1/Th2 cytokine production in the lungs with increased interferon (IFN)-γ levels and decreased interleukin (IL)-4 levels, decreased the percentage of Th2 and increased both the percentage of Th1 and T(reg) cells in the lungs of OVA-sensitized/challenged mice. This research demonstrates that DC-CTL4Ig reduces airway hyperresponsiveness effectively and prevents airway inflammation in OVA-sensitized/challenged mice, which is due most probably to attenuated secretion of Th2 cytokines and increased secretion of Th1 cytokines in the local airway, and the correction of the pulmonary imbalance between Th1/Th2 cells and Th2/T(reg) cells.     

Clinical and immunological effects of low-dose IFN-alpha treatment in patients with corticosteroid-resistant asthma

BACKGROUND: Interferon (IFN)-alpha is a cytokine that possesses potent anti-viral and immunoregulatory activities. We aimed to assess clinical and immunological effects of low-dose IFN-alpha in patients with severe corticosteroid-resistant asthma with and without Churg-Strauss syndrome. There is currently no efficient pharmacological treatment available for this group of patients. METHODS: We studied 10 patients with corticosteroid-resistant asthma, in which 3x10(6) IU/day IFN-alpha were administrated in addition to the prednisone dose given already before introduction of the cytokine therapy. The prednisone dose was gradually reduced dependent on the clinical situation and used as a clinical readout to evaluate the efficacy of the cytokine therapy. To distinguish between IFN-alpha- and prednisone-mediated immunological changes, the corticosteroid dose was kept constant for at least 2 weeks upon introduction of the cytokine therapy in seven patients. The effects of treatment on clinical and immunological parameters were measured at 2-4 weeks and 5-10 months depending on the availability of the patient. RESULTS: Interferon-alpha treatment rapidly improved the clinical situation as assessed by lung function parameters and required prednisone dose. Important immunological changes included: decreased leukocyte numbers, increased relative numbers of CD4+ T cells, increased differentiation of T helper (Th)1 cells, and increased expression of interleukin (IL)-10 in peripheral blood mononuclear cells. CONCLUSION: Interferon-alpha treatment was associated with dramatic improvements in the condition of patients with corticosteroid-resistant asthma with and without Churg-Strauss syndrome. Potential mechanisms of action include the establishment of a correct Th1/Th2 balance and the induction of the anti-inflammatory IL-10 gene.     

Role of STAT6 and SMAD2 in a model of chronic allergen exposure: a mouse strain comparison study

Background Asthma is a disease characterized by variable and reversible airway obstruction and is associated with airway inflammation, airway remodelling (including goblet cell hyperplasia, increased collagen deposition and increased smooth muscle mass) and increased airway responsiveness. It is believed that airway inflammation plays a critical role in the development of airway remodelling, with IL‐13 and TGF‐β1 pathways being strongly associated with the disease progression. Mouse models of asthma are capable of recapitulating some components of asthma and have been used to look at both IL‐13 and TGF‐β1 pathways, which use STAT6 and SMAD2 signalling molecules, respectively. Objectives Using brief and chronic models of allergen exposure, we utilized BALB/c and C57Bl/6 to explore the hypothesis that observed differences in responses to allergen between these mouse strains will involve fundamental differences in IL‐13 and TGF‐β1 responses. Methods The following outcome measurements were performed: airway physiology, bronchoalveolar lavage cell counts/cytokine analysis, histology, immunoblots and gene expression assays. Results We demonstrate in BALB/c mice an IL‐13‐dependent phosphorylation of STAT6, nuclear localized in inflammatory cells, which is associated with indices of airway remodelling and development of airway dysfunction. In BALB/c mice, phosphorylation of SMAD2 is delayed relative to STAT6 activation and also involves an IL‐13‐dependent mechanism. In contrast, despite an allergen‐induced increase in IL‐4, IL‐13 and eosinophils, C57Bl/6 demonstrates a reduced and distinct pattern of phosphorylated STAT6, no SMAD2 phosphorylation changes and fail to develop indices of remodelling or changes in airway function. Conclusion The activation of signalling pathways and nuclear translocation of signalling molecules downstream of IL‐13 and TGF‐β1 further support the central role of these molecules in the pathology and dysfunction in animal models of asthma. Activation of signalling pathways downstream from IL‐13 and TGF‐β1 may be more relevant in disease progression than elevations in airway inflammation alone.     

Association between beta2-adrenoceptor polymorphisms and asthma diagnosis among Mexican adults

BACKGROUND: Recent studies demonstrate that genetic variations in the human beta(2)-adrenergic receptor (beta(2)AR) structure at codons 16 and 27 alter receptor function in vitro and are associated with asthma severity and airway hyperresponsiveness but have not been linked to asthma diagnosis. The nature of the relation in a more homogeneous population is uncertain. OBJECTIVE: We determined frequencies of these polymorphisms to explore the association between beta(2)AR haplotypes and asthma diagnosis and phenotype. METHODS: This is a population-based, case-control study that involves a total sample of 907 unrelated Mexican Mestizos. Genotyping at beta(2)AR was identified by polymerase chain reaction-restriction fragment length polymorphism analysis. Multivariate logistic regression analysis was used to estimate the odds ratio (OR) of the association between beta(2)AR haplotype status and asthma diagnosis. RESULTS: A significant inverse association was found between subjects with Glu27 allele (OR, 0.5; 95% CI, 0.4 to 0.7) and Gly16-Glu27 alleles (OR, 0.5; 95% CI, 0.3 to 0.8) and asthma. Sex differences in this association were explored, given the complex relation between sex and asthma. Among men, a positive association was present between the "Gly16 allele without Glu27" (OR, 2.9; 95% CI, 1.26 to 6.8) and asthma. In contrast, a lower risk of asthma was found among women Gly16-Glu27 alleles (OR, 0.3; 95% CI, 0.2 to 0.6). Nocturnal asthma was associated with the Gly16 allele (OR, 1.8; 95% CI, 1.3 to 2.6). CONCLUSIONS: Variation in the beta(2)AR gene is associated in the pathogenesis of asthma and acts as a disease modifier in nocturnal asthma.