大蒜新素治疗小鼠巨细胞病毒性心肌炎作用研究

目的探讨大蒜新素对小鼠巨细胞病毒(MCMV)性心肌炎治疗作用及其抗CMV机制. 方法 60只BALB/c小鼠随机分成大蒜新素治疗组(20只)、安慰剂组(20只)和正常对照组(20只).大蒜新素治疗组接种MCMV K181后24 h开始用大蒜新素一般剂量(25 mg/kg)腹腔注射,每天1次,共14 d;安慰剂组和正常对照组仅用等量生理盐水.各组分别于治疗后第3、5、7、14天各处死5只小鼠,观察小鼠心肌组织病理损害;用双抗体夹心ELISA法检测小鼠心肌组织细胞因子IFN-γ表达水平;用RT-PCR方法检测小鼠脾核转录因子T-bet mRNA表达强度. 结果 MCMV感染下调小鼠T-bet mRNA和TH1类细胞因子IFN-γ的表达(P＜0.01);大蒜新素能诱导MCMV性心肌炎模型小鼠转录因子T-bet mRNA和细胞因子IFN-γ的表达显著增加(P＜0.01),并显著改善MCMV感染小鼠心肌组织病理损害(P＜0.05). 结论大蒜新素通过上调转录因子T-bet mRNA表达进而促进TH1类细胞因子IFN-γ分泌,诱导和促进TH1优势应答反应,增强机体特异性细胞免疫功能而发挥抗MCMV作用.     

急慢性MCMV感染对小鼠脾细胞Foxp3/T-bet/GATA-3蛋白表达水平的影响

目的：在整体水平研究鼠巨细胞病毒（MCMV）感染对小鼠辅助性T细胞亚群Th1、Th2和调节性T细胞（Treg）分化特异性转录因子T-bet、GATA-3和Foxp3蛋白表达水平的影响。方法：建立MCMV播散型感染模型,依据主要脏器内病毒滴度,确定感染后28天为本模型急、慢性期界定点。42只模型鼠分别于接种MCMV Smith株后第1、3、7、14、28、45天和60天各处死6只,分离脾细胞;另设42只正常小鼠作为模拟感染对照。Western blot法检测脾细胞中特异转录因子T-bet、GATA-3和Foxp3蛋白表达水平。结果：MCMV感染后第3天T-bet蛋白表达显著增高达峰值,与模拟感染对照组比较有显著差异（P〈0.01）,随后下降,第28天后降至模拟感染对照组相当水平;而GATA-3蛋白表达在感染后第3天开始升高,第7天达峰值（P〈0.01）,第14天开始缓慢下降,但至第60天仍显著高于模拟感染对照组（P〈0.05）;Foxp3蛋白表达在感染后7天明显低于模拟感染对照组,第28天降至最低（P〈0.01）,第45天和60天表达明显上调,并显著高于模拟感染对照组水平（P〈0.05）。结论：感染急性期,MCMV上调Th1/Th2特异性转录因子T-bet和GATA-3的蛋白表达;感染慢性期,MCMV诱导Treg特异性转录因子Foxp3蛋白表达上调,同时显著抑制T-bet和GATA-3蛋白表达,提示CMV诱导Foxp3表达增加可能是其抑制宿主抗病毒免疫,导致慢性持续性感染的重要原因。     

CD4+CD25+调节性T细胞抑制效应性T细胞在MCMV感染中的免疫作用

目的 通过细胞水平探讨CD4+CD25+调节性T细胞(Treg)在T淋巴细胞与感染小鼠巨细胞病毒(MCMV)的小鼠胚胎成纤维细胞(MEF)共培养体系中发挥的免疫作用.方法 建立小鼠T细胞与感染MCMV的同系MEF(MEFMCMV)体外共培养细胞模型.通过噬斑法检测共培养上清中感染性病毒量;Western blot方法检测辅助性T细胞亚群TH1/TH2特异性转录因子T-bet/GATA-3蛋白表达水平;ELISA法检测共培养上清中细胞因子IL-4、IL-10和IFN-γ表达水平.结果 去除Treg的T细胞(TdepTreg)与MEFMCMV共培养3 d后可显著减少上清中的感染性病毒量;同时THl/TH2上游特异性转录因子T-bet/GATA.3和下游细胞因子IL-4、IL-10和IFN-γ的蛋白质表达水平显著升高.向共培养体系中添加Treg后病毒负荷量显著增加;T-bet/GATA-3和IFN-γ蛋白表达水平下降;IL-10蛋白表达水平在Treg比率为1%～2%时与TdepTreg组比较无显著差异,在Treg比率增至5%～20%时较TdepTreg组显著增加;而IL-4表达水平与TdepTreg组比较无显著差异,上述效应均与Treg添加比率成剂量相关性.结论 巨细胞病毒感染小鼠成纤维细胞后能激活效应性T细胞增殖活化,而Treg可抑制效应性T细胞在MCMV感染中的免疫保护作用.     

鼠巨细胞病毒感染对小鼠脾细胞IL-12 p35和p40基因转录和表达的影响

目的 探讨鼠巨细胞病毒（MCMV）感染对小鼠脾细胞内TH-1细胞调控因子白细胞介素-12（IL-12）p35和p40基因转录和表达影响的时序性变化特点。方法 制备全身播散型MCMV感染小鼠模型，于感染后3d,5d、7d、10d和14d分离小鼠脾细胞，在PHA刺激后用RT-PCR法检测脾细胞内IL-12 p35和p40 mRNA水平时序性变化，ELISA法测定脾细胞培养上清中IL-12 p70和IFN-γ蛋白水平变化。结果 模型鼠在感染后第3天IL-12 p70表达显著增高（P〈0．05），但第5天后急剧下降，显著低于正常鼠（P〈0．05）；IFN-γ在感染后第3天增高达峰值（P〈0．01），随后逐渐下降，在感染后第10～14天降至正常水平；IL-12 p35mRNA水平变化与IL-12 p70完全一致；而p40mRNA则从感染第3天开始持续高水平表达（P〈0．01）。结论 IL-12 p35mRNA和IL-12 p70在感染5d后持续明显下降是感染后期TH1类细胞因子持续低表达、TH1反应受抑制的主要原因之一；感染后IL-12 p40mRNA持续高水平可能导致拮抗剂（p40）2表达增加，后者可进一步抑制IL-12功能。     

吡格列酮对哮喘模型TH1/TH2细胞因子表达的影响

目的 初步探讨过氧化物酶增殖活化受体-γ（PPAR-γ）激动剂吡格列酮对哮喘模型TH1/TH2细胞因子表达的影响及其机制。方法 18只BALB／c小鼠随机分为正常对照组、哮喘组和药物组，每组各6只。采用Western blot方法检测各组小鼠肺组织T-bet和GATA3的表达，同时运用流式细胞仪检测小鼠脾细胞胞内细胞因子白细胞介素4（IL-4）和干扰素-γ（IFN-γ）的表达。结果 哮喘组肺组织T-bet的表达与正常对照相比显著升高（P〈0．01），GATA3无显著变化（P〉0．05）；经吡格列酮治疗的小鼠肺组织T-bet的表达与哮喘鼠比显著增高（P〈0．01），而GATA3无显著变化（P〈0．05）。哮喘鼠T细胞内IL-4／WN-γ比值与正常组相比明显升高（P〈0．01）；经吡格列酮治疗后细胞内IL-4，IFN-γ比值明显降低（P〈0．01）。结论 PPAR-γ激动剂吡格列酮可能通过参与调控TH1细胞转化过程中重要转录因子T-bet的表达，改变IL-4／IFN-γ比值，从而改善相应的炎性症状，PPAR-γ可能成为哮喘治疗的新靶点。     

转录因子T-bet/GATA-3在致敏大鼠脾CD4+T细胞中失衡表达和调节的研究

目的 探讨转录因子T-bet/GATA-3在卵白蛋白(OVA)致敏大鼠脾CD4+T细胞中失衡表达,及地塞米松和咪喹莫特对其的调节作用.方法 从SD大鼠脾脏中分离获得CD4+T细胞,ELISA法测定细胞上清液中细胞因子IL-4、IL-5和IFN-γ含量;Western blot检测CD4+T细胞中T-bet和GATA-3表达.结果 在4个时间点培养细胞上清液中,空白对照组检测到低水平IFN-γ;随着培养时间延长,阳性对照组IL-4和IL-5持续增加,IFN-γ保持在低水平.地塞米松干预组IL-4、IL-5和IFN-γ低表达,均低于空白对照组(P＜0.01);咪喹莫特干预组IL-4和IL-5表达降低,IFN-γ表达增强.此作用从培养6 h开始,12 h达高峰,持续至24 h.在4个时间点培养细胞中,空白对照组检测到转录因子T-bet和GATA-3蛋白表达;随着细胞培养时间延长,阳性对照组T-bet表达降低,GATA-3表达增加.地塞米松干预组T-bet低表达,GATA-3在24 h内表达水平无明显变化;咪喹莫特干预组与阳性对照组比较,GATA-3表达降低,T-bet表达增强.此作用从细胞培养6 h开始,12 h达高峰,持续至24 h.结论 OVA致敏大鼠脾CD4+T细胞中,转录因子T-bet/GATA-3失衡表达,即T-bet低表达,GATA-3异常高表达;地塞米松抑制CD4+T细胞中T-bet表达,对GATA-3表达无明显作用;咪喹莫特通过调节CD4+T细胞中T-bet和GATA-3平衡表达,纠正TH1和TH2细胞的失衡,提示咪喹莫特可能在由TH2细胞介导免疫异常的哮喘中发挥作用.     

地塞米松对实验性哮喘小鼠TH1/TH2细胞因子的影响及其机制的探讨

目的：初步探讨地塞米松对小鼠哮喘模型哮喘进展过程中T_H细胞因子的影响及其机制。方法： 18只BALB/c小鼠随机分为正常对照组、哮喘组和地塞米松处理组，每组各6只。运用流式细胞仪检测小鼠脾细胞胞内细胞因子白细胞介素-4和干扰素-γ的表达,用Western blotting方法检测各组小鼠肺组织转录因子 T-bet 和GATA-3的表达，用组织学观察肺组织炎症程度。结果：哮喘鼠T细胞内IL-4/IFN-γ比值明显高于正常组（P﹤0.01）；地塞米松组细胞内IL-4/IFN-γ比值明显低于哮喘组（P﹤0.01）。哮喘组肺组织T-bet的表达明显低于正常对照组（P﹤0.01），GATA-3明显高于正常对照组（P﹤0.01）;地塞米松组的小鼠肺组织T-bet和GATA-3的表达均明显低于哮喘组（P﹤0.01）， GATA-3降低更为明显。结论：调控T_H1和T_H2细胞转化过程中重要转录因子T-bet和GATA-3的表达，可以改变IL-4/IFN-γ比值，纠正哮喘的T_H2漂移，从而改善相应的炎性症状，这可能是地塞米松抑制哮喘的重要机制之一。     

BALB/c小鼠感染弓形虫后Thl/Th2免疫漂移的实验研究

目的:动态分析BALB/c小鼠感染弓形虫后Thl/Th2免疫失衡及免疫漂移特点,并探讨转录因子T-bet和GA.TA-3在此过程中的改变及其意义.方法:90只BALB/c小鼠随机分为正常对照组30只,弓形虫感染组60只.于感染后奇数天每天处死感染组小鼠2只,对照组小鼠1只,采用ELISA法动态检测各组小鼠血清中IFN-γ和IL-4的水平,同时应用荧光定量PCR方法检测小鼠脾细胞中T-bet和GATA-3 mRNA的表达情况.结果:感染组小鼠中,血清IFN-γ于感染后第4天开始显著升高,第5~7天维持在高峰值,从第8天开始下降,第9天降至正常水平;IL-4于感染后第8天开始显著升高,第9天升至峰值,从第14天开始下降,第15天降至正常水平;脾细胞T-bet mRNA的表达在感染后第3天升高,第5天达高峰后于第9天降至正常水平;脾细胞GATA-3 mRNA的表达在感染后第7天升高,第11天达高峰,于第13天降至正常水平.正常对照组小鼠在实验期内IFN-γ、IL-4水平没有明显变化,维持在正常的较低水平.结论:BALB/c小鼠感染弓形虫后诱导的免疫应答在感染急性期(第1-8天)以Th1应答为主,第9至13天,宿主免疫应答以Th2细胞应答为主,之后Thl/Th2应答基本恢复平衡.Thl应答向Th2应答的漂移与T-bet和GATA-3 mRNA的表达相关并受其调控,Thl/Th2型免疫应答的发生时相和效应强度可能影响弓形虫感染的最终结局.     

黄芪在树突状细胞水平对哮喘TH 1/TH 2平衡的调节作用

目的 探讨黄芪在树突状细胞(DC)水平对过敏性哮喘TH/TH2平衡的调节作用.方法 用rhGM-CSF和rhIL-4诱导培养外周血来源的DC并予鉴定,ELISA法检测其分泌的细胞因子IL-12、IL-10以及与自身T细胞反应后,RT-PCR检测T-bet和GATA-3 mRNA含量,流式细胞术检测T细胞分泌的胞内细胞因子IL-4和IFN-γ水平.结果 哮喘患儿外周血DC分泌IL-10高于对照组(P＜0.05);黄芪干预后DC分泌IL-10降低,与哮喘组比较差异有统计学意义(P＜0.05).哮喘患儿外周血DC分泌IL-12低于对照组(P＜0.05);黄芪干预后DC分泌IL-12增加,但与哮喘组比较差异无统计学意义.混合培养第7天哮喘组T细胞内IL-4水平显著高于正常对照组(P＜0.01);而IFN-γ水平则显著低于正常对照组(P＜0.05);哮喘组IL-4/IFN-γ比值高于正常对照组(P＜0.01).黄芪干预后T细胞内IL-4水平与哮喘组比较差异无统计学意义,而IFN-γ水平增加,与哮喘组比较差异有统计学意义(P＜0.05),IL-4/IFN-γ比值降低,与哮喘组比较差异有统计学意义(P＜0.01).哮喘组T-bet mRNA的表达强度明显低于正常对照组(P＜0.01);而哮喘组GATA-3 mRNA的表达强度则明显高于正常对照组(P＜0.05);哮喘组GATA-3/T-bet比值高于正常对照组(P＜0.05).黄芪干预后T细胞GATA-3 mRNA的表达强度与哮喘组比较差异无统计学意义,而T-bet mRNA水平增加,与哮喘组比较差异有统计学意义(P＜0.05),GATA-3/T-bet比值降低,与哮喘组比较差异有统计学意义(P＜0.01).结论 哮喘患儿DC功能缺陷,产生IL-12减少、IL-10增加导致TH2优势分化,从而使TH1/TH2平衡向TH2倾斜,合成IFN-γ减少,进而造成气道慢性炎症、气道高反应性而致哮喘发作.黄芪对DC的调节主要通过降低IL-10的分泌水平,从而降低其抑制TH0细胞向TH 1分化的功能,即间接抑制了TH0细胞向TH2的分化.     

BALB/c小鼠感染弓形虫后Th1/Th2免疫漂移的实验研究

目的：动态分析BALB/c小鼠感染弓形虫后Th1/Th2免疫失衡及免疫漂移特点,并探讨转录因子T-bet和GA-TA-3在此过程中的改变及其意义。方法：90只BALB/c小鼠随机分为正常对照组30只,弓形虫感染组60只。于感染后奇数天每天处死感染组小鼠2只,对照组小鼠1只,采用ELISA法动态检测各组小鼠血清中IFN-γ和IL-4的水平,同时应用荧光定量PCR方法检测小鼠脾细胞中T-bet和GATA-3 mRNA的表达情况。结果：感染组小鼠中,血清IFN-γ于感染后第4天开始显著升高,第5~7天维持在高峰值,从第8天开始下降,第9天降至正常水平;IL-4于感染后第8天开始显著升高,第9天升至峰值,从第14天开始下降,第15天降至正常水平;脾细胞T-bet mRNA的表达在感染后第3天升高,第5天达高峰后于第9天降至正常水平;脾细胞GATA-3 mRNA的表达在感染后第7天升高,第11天达高峰,于第13天降至正常水平。正常对照组小鼠在实验期内IFN-γI、L-4水平没有明显变化,维持在正常的较低水平。结论：BALB/c小鼠感染弓形虫后诱导的免疫应答在感染急性期（第1~8天）以Th1应答为主,第9至13天,宿主免疫应答以Th2细胞应答为主,之后Th1/Th2应答基本恢复平衡。Th1应答向Th2应答的漂移与T-bet和GATA-3 mRNA的表达相关并受其调控,Th1/Th2型免疫应答的发生时相和效应强度可能影响弓形虫感染的最终结局。     

Biology of human TH1 and TH2 cells

Evidence is accumulating to suggest the existence of polarized human T-cell responses, reminiscent of T_H1 and T_H2 subsets described for mouse T cells. Human T_H1 cells preferentially develop during infections by intracellular bacteria and trigger phagocyte-mediated host defense, whereas T_H2 cells, which predominate during helminthic infestations and in response to common environmental allergens, are responsible for phagocyte-independent host response. Human T_H1 and T_H2 cells exhibit not only different functional properties but probably also distinct surface markers; T_H2, but not T_H1, clones express membrane CD30 and release the soluble form of CD30, a member of the TNF receptor superfamily. The cytokine profile of natural immunity evoked by different offending agents in the context of different host genetic backgrounds appears to be the most critical factor in determining the phenotype of the subsequent specific response. IL-12 and IFN- and produced by macrophages and NK cells favor the development of T_H1 cells, whereas the early production of IL-4 by a stillunidentified cell type favors the development of T_H2 cells. Clearly, polarized human T_H1 and T_H2 responses not only play different roles in protection, they can also promote different immunopathological reactions. Strong and persistent T_H1 responses seen to be involved in organ-specific autoimmunity, contact dermatitis, and some chronic inflammatory disorders of unknown etiology. In contrast, polarized T_H2 responses favor a reduced protection against the majority of infectious agents (including HIV) and, in genetically predisposed hosts, are responsible for triggering of allergic atopic disorders.     

Genetic polymorphism and TH1/TH2 orientation

BACKGROUND: It is likely that besides developmental and environmental factors, genetic factors also play an important role in Th1/Th2 orientation and susceptibility to related disorders. Thus, for each genetic factor involved one would expect an opposite pattern of susceptibility towards Th1- and Th2-associated diseases. METHODS: We report a comparative analysis of the pattern of association of four genetic polymorphisms with bronchial asthma (Th2 disease) and Crohn's disease (CD; Th1 disease). The study population included 291 Roman children with bronchial asthma and 72 adult Romans with CD, and haptoglobin, adenosine deaminase (ADA), acid phosphatase locus 1 (ACP1) and MN phenotypes were determined. RESULTS: Compared with controls from the same population, the pattern of phenotype association observed in bronchial asthma is exactly opposite to that observed in CD. The analysis of pairwise gametic type distribution for ACP1, ADA and MN polymorphisms has shown that the pattern of differences between bronchial asthma and controls is opposite to that observed between CD and controls. CONCLUSIONS: The pattern of differences between bronchial asthma versus CD is compatible with the hypothesis that some of the genetic systems considered contribute to Th1/Th2 orientation.     

Coevolution of TH1, TH2, and TH17 responses during repeated pulmonary exposure to Aspergillus fumigatus conidia

Aspergillus fumigatus, a ubiquitous airborne fungus, can cause invasive infection in immunocompromised individuals but also triggers allergic bronchopulmonary aspergillosis in a subset of otherwise healthy individuals repeatedly exposed to the organism. This study addresses a critical gap in our understanding of the immunoregulation in response to repeated exposure to A. fumigatus conidia. C57BL/6 mice were challenged intranasally with A. fumigatus conidia weekly, and leukocyte composition, activation, and cytokine production were examined after two, four, and eight challenges. Approximately 99% of A. fumigatus conidia were cleared within 24 h after inoculation, and repeated exposure to A. fumigatus conidia did not result in hyphal growth or accumulation of conidia with time. After 2 challenges, there was an early influx of neutrophils and regulatory T (T(reg)) cells into the lungs but minimal inflammation. Repeated exposure promoted sustained expansion of the draining lymph nodes, while the influx of eosinophils and other myeloid cells into the lungs peaked after four exposures and then decreased despite continued A. fumigatus challenges. Goblet cell metaplasia and low-level fibrosis were evident during the response. Repeated exposure to A. fumigatus conidia induced T cell activation in the lungs and the codevelopment by four exposures of T(H)1, T(H)2, and T(H)17 responses in the lungs, which were maintained through eight exposures. Changes in CD4 T cell polarization or T(reg) numbers did not account for the reduction in myeloid cell numbers later in the response, suggesting a non-T-cell regulatory pathway involved in dampening inflammation during repeated exposure to A. fumigatus conidia.     

Immunologic influences on allergy and the TH1/TH2 balance

TH2 cell-mediated immune responses against "innocuous" antigens play a triggering role in atopic allergy. Several epidemiologic studies have clearly shown that the reduced microbial exposure of children caused by the westernized lifestyle is responsible for the increased prevalence of allergy that has occurred in the last decades in developed countries ("hygiene hypothesis"). The immunologic changes caused by the reduced exposure to pathogenic and nonpathogenic microbes during childhood are still controversial. The initial interpretation has been a lack of shift of allergen-specific responses from the TH2 to the TH1 phenotype. This is because of reduced production of IL-12 and IFNs by cells of the natural immunity stimulated by bacterial products through their Toll-like receptors (missing immune deviation). Another interpretation emphasizes the importance of reduced activity of T-regulatory cells (reduced immune suppression). However, although there are impressive amounts of data in favor of the missing immune deviation, experimental evidence supporting the role of reduced immune suppression in explaining the increased prevalence of allergy is currently weak or even contradictory. The solution to this question is very important not only from a theoretic point of view but also because of its therapeutic implications.