特异性免疫治疗对哮喘小鼠的作用及机制的初步研究

目的　探讨特异性免疫治疗对哮喘小鼠的作用及其可能机制。方法　通过卵蛋白 (OVA)皮下注射的方法对致敏小鼠进行特异性免疫治疗 ,观察肺组织病理、支气管肺泡灌洗液 (BALF)细胞计数及分类、ELISA检测血清OVA特异性IgE(sIgE)及脾脏T淋巴细胞IL 2和IL 4的分泌 ,3H TdR掺入法检测T淋巴细胞的增殖反应 ,并与OVA致敏及激发的哮喘小鼠相比较。结果　哮喘特异性免疫治疗明显抑制小鼠肺组织炎症病理改变 ;BALF中细胞总数及嗜酸性粒细胞 (EOS)数显著减少 (P <0 .0 5 ) ;血清sIgE显著降低 (P <0 .0 5 ) ;T淋巴细胞IL 2和IL 4的分泌显著降低 (P <0 .0 5 ) ;T淋巴细胞对OVA的特异性刺激的反应显著降低 (P <0 .0 5 )。结论　特异性免疫治疗可显著抑制哮喘小鼠的炎症反应 ;诱导T淋巴细胞无能可能是特异性免疫治疗减轻哮喘相关炎症反应的机制之一     

OVA特异性免疫治疗对哮喘小鼠IL-23/Th17轴的影响及机制研究

目的腹部皮下注射大剂量卵白蛋白(OVA)建立小鼠哮喘免疫治疗模型,探讨IL-23/Th17轴在小鼠哮喘模型经皮免疫治疗过程中的作用。方法选择18只BALB/c小鼠为建模研究对象,按随机数字表法分为3组:空白对照组、哮喘对照组和哮喘免疫治疗组,每组6只小鼠。哮喘免疫治疗组予10μg OVA于0、7 d腹腔注射致敏,21~27 d持续1周予1 mg OVA腹部皮下注射诱导免疫耐受,35~41 d予1%OVA雾化激发;哮喘对照组在21~27 d OVA皮下注射等量生理盐水,其余处置同哮喘免疫治疗组;空白对照组采用等量生理盐水致敏及激发。50 d予10%OVA加强激发1次。末次激发24 h内检测气道反应性;收集支气管肺泡灌洗液(BALF)计数细胞总数及细胞分类计数;ELISA法检测血清OVA特异性Ig E、BALF中IL-5、IFN-γ、IL-23、IL-10的表达;HE染色观察肺组织病理改变;流式细胞仪检测各组脾、肺组织Treg、Th17细胞比例;q-PCR检测肺组织转录因子。结果哮喘免疫治疗组气道反应性、BALF中嗜酸性粒细胞计数、IL-23水平及血清OVA特异性Ig E水平明显低于哮喘对照组,差异有统计学意义(P0.05);而BALF中IFN-γ水平与哮喘对照组比较差异无统计学意义(P0.05);同时HE染色发现哮喘免疫治疗组肺组织炎症较哮喘对照组明显减轻;流式细胞技术检测发现外周血Treg细胞百分比明显高于哮喘对照组,差异有统计学意义(P0.05);q-PCR检测肺组织转录因子表明免疫治疗组Foxp3明显高于哮喘对照组,而RORγt明显低于哮喘对照组,差异均具有统计学意义(P0.05)。结论大剂量OVA特异性免疫治疗能够减轻哮喘小鼠气道慢性炎症反应,同时引起Th17细胞下降伴随IL-23表达降低;其机制可能与纠正肺部IL-23/Th17轴有关。     

肺脏树突状细胞表面共刺激分子在小鼠哮喘模型中的表达

目的 通过检测哮喘小鼠肺组织中树突状细胞(dendritic cells,DC)表面共刺激分子的表达以及细胞因子分泌的能力,探讨哮喘发生免疫耐受缺陷的原因.方法 Balb/c小鼠60只,分为3组(每组20只):哮喘组、磷酸盐缓冲液(PBS)对照组、健康对照组.对3组小鼠取肺组织做病理观察,行支气管肺泡灌洗液(BALF)计数细胞并分类,ELISA检测血清特异性IgE(sIgE)及BALF中细胞因子的水平.分离、培养肺脏DC,用流式细胞仪(FACS)测CD11c表达,并进一步用FACS分析哮喘小鼠DC表面共刺激分子CD11cCD80、CD11cCD86表达的变化.结果 哮喘小鼠肺组织表现为以嗜酸性粒细胞、淋巴细胞浸润为主的炎症改变,BALF中嗜酸性粒细胞计数显著增加(P＜0.01),血清sIgE水平显著升高(P＜0.01).与PBS对照组比较,哮喘小鼠CD11cCD80、CD11cCD86表达上调(P＜0.01),其分泌IL-10细胞因子的水平明显下降.结论 肺脏DC可能通过上调CD11cCD80、CD11cCD86在哮喘的免疫耐受缺陷中发挥作用.     

γδT细胞与哮喘特异性致敏原皮下脱敏疗法的研究

目的　探讨支气管哮喘γδT细胞与特异性致敏原脱敏疗法的关系 ,了解γδT细胞在哮喘发病机制中的作用。方法　应用卵清蛋白 (OVA)致敏并刺激Wistar大鼠 ,制作致敏大鼠哮喘模型 ;再用OVA皮下注射脱敏 ;观察脱敏前后OVA激发反应 ,测定气道反应性 (PC50 ) ;肺组织切片做HE染色观察炎症改变和做原位杂交检测IL 4mRNA和IFN γmRNA表达 ,并采用免疫组化法检测肺组织中γδT细胞数量 ;用ELISA法检测血清IL 4和IFN γ浓度 ,用流式细胞术检测PBMC和支气管肺泡灌洗液 (BALF)中γδTCR阳性T细胞百分率。结果　在脱敏组 (C组 ) ,用脱敏前激发浓度的OVA激发不再有明显哮喘发作 ,支气管肺内嗜酸细胞 (Eos)消失、过敏性炎症消除 ,其PC50 与对照组 (即D组和E组 )比较差异均有显著性 (均为P <0 .0 1)、而与正常组 (即A组 )比较差异无显著性 (P >0 .0 5 ) ;C组肺内IL 4mRNA表达及血清IL 4浓度均明显低于D、E组 (均为P <0 .0 1) ,而C组肺内IFN γmRNA表达及血清IFN γ浓度均明显高于A、D、E组 (均为P <0 .0 1) ;与此同时 ,C组肺组织内及BALF中γδT细胞数量则明显低于D、E组 (P <0 .0 1或P <0 .0 5 )。结论　特异性致敏原皮下脱敏疗法能纠正哮喘TH1 TH2反应失衡 ,同时伴随肺内及外周血γδT细胞异常分布的恢复 ,提示γδT     

CTLA-4在超抗原诱导T细胞无能中的作用研究

目的 探讨CTLA—4对T细胞无能的诱导作用。方法 通过使用超抗原SEA作为一种无能诱导剂，建立体外无能模型，检测了无能T细胞在受到SEA的再次刺激时其膜分子CD28和CTLA—4的表达。结果 与活化T细胞相比，无能T细胞在免疫应答的后期阶段表面表达高水平的CTLA—4分子，而CD28的表达则只较活化组T细胞稍高一些。结论 CTLA—4表面表达水平的升高很可能与T细胞无能状态的诱导有关。     

牛磺酸对内质网应激介导的过敏性哮喘小鼠气道炎症的影响

目的 探讨牛磺酸（taurine）对过敏性哮喘小鼠气道炎症的影响及其可能的作用机制。方法将24只C57BL/6小鼠随机分为对照组、模型组与牛磺酸组,每组8只,利用卵蛋白（OVA）致敏加激发的方式建立小鼠过敏性哮喘模型。第28 d时处死小鼠,HE染色检测肺组织病理损伤;酶联免疫吸附法（ELISA）检测小鼠血清中OVA特异性免疫球蛋白（OVA-IgE）的表达;ELISA检测小鼠肺泡灌洗液（BALF）中炎症因子白介素（interleukin,IL）-4、IL-5、IL-13及干扰素γ(Interferon,IFN-γ)表达;检测BALF中炎性细胞数量;Western blot检测肺组织中葡糖调节蛋白78(GRP78)、转录因子C/EBP同源蛋白（CHOP）、核因子κ-B(NF-κB)的蛋白表达。结果 牛磺酸可显著改善过敏性哮喘小鼠肺组织病理损伤,降低血清中OVA-IgE含量,降低BALF中炎性因子IL-4、IL-5及IL-13的表达,增加IFN-γ的表达,并显著降低BALF中炎性细胞数量。牛磺酸还能够显著降低过敏性哮喘小鼠肺组织中GRP78、CHOP和NF-κB总蛋白表达。结论 牛磺酸能够抑...     

糖皮质激素对哮喘小鼠CD4~+T细胞中miRNA-155表达调控的研究

目的:探讨糖皮质激素对哮喘小鼠CD4~+ T细胞中微小RNA-155(miRNA-155)表达调控的影响。方法:使用糖皮质激素对卵清蛋白诱导的小鼠哮喘模型进行治疗,观察糖皮质激素对哮喘小鼠肺组织病理学、肺组织及CD4~+ T细胞中miRNA-155表达和支气管肺泡灌洗液(BALF)中细胞因子含量的影响。结果:RT-qPCR结果显示,哮喘小鼠肺组织和脾脏CD4~+ T细胞中miRNA-155表达显著升高,随着接触过敏原时间的增加,CD4~+ T细胞中miRNA-155水平显著升高(P0.01)。HE和PAS染色显示,与对照组相比,模型小鼠肺组织中炎性细胞浸润显著增加,给予糖皮质激素治疗后可明显减轻支气管周围和血管周围炎症,减少增生杯状细胞的黏液分泌。糖皮质激素治疗后哮喘小鼠肺组织中的miRNA-155水平显著降低,CD4~+ T细胞中的miRNA-155水平显著下调。糖皮质激素治疗可抑制哮喘小鼠的脾脏中CD4~+ CD8~-细胞比例的增加,减少哮喘小鼠肺组织中CD4~+ T细胞的聚集。糖皮质激素治疗后BALF中白细胞介素4(IL-4)、IL-5和IL-13水平下降,干扰素γ水平显著增加。结论:糖皮质激素可抑制哮喘小鼠肺组织中CD4~+ T细胞的聚集,并可降低肺组织和脾脏中CD4~+ T细胞的miRNA-155的表达。     

过继转输的胚胎抗原耐受T细胞在妊娠小鼠体内细胞因子及协同刺激分子的表达特征

目的 :分析过继转输的小鼠胚胎抗原耐受T细胞内细胞因子及细胞表面协同刺激分子的表达特征。方法 :以♀CBA/J×♂DBA/ 2为自然流产模型 ,将自然流产模型CBA/J孕鼠于孕 4天 (着床期 )分别腹腔注射大鼠抗小鼠CD80和CD86mAb或大鼠同型IgG。于孕 9天 ,应用免疫磁珠阴性分选两组孕鼠的脾脏T细胞 ,将T细胞进行碳氧氢化荧光素双乙酸盐琥珀酰亚胺酯 (CFSE)体外荧光标记 ,再分别过继转输至孕 4天的CBA/J×DBA/ 2孕鼠。在宿主孕鼠孕第 9天 ,处死小鼠取脾细胞 ,用流式细胞术分析在DBA/ 2父系抗原刺激下过继转输的T细胞细胞因子IL 2、IL 4、IL 10和IFN γ及协同刺激分子CD2 8和CTLA 4的表达。结果 :与过继转输的胚胎抗原非耐受T细胞相比 ,过继转输的胚胎抗原耐受T细胞IL 10的表达显著增加 ,IL 2和IFN γ的表达则显著下降 (P <0 0 5 ) ,IL 4的表达无明显改变 (P >0 0 5 ) ;细胞表面CD2 8的表达显著下降 ,而CTLA 4的表达却显著增加 (P <0 0 5 )。结论 :过继转输的小鼠胚胎抗原耐受T细胞内Th2型细胞因子和表面CTLA 4表达上调 ,而Th1型细胞因子和表面CD2 8的表达则下降。胚胎抗原耐受T细胞通过Th2型细胞因子表达优势和协同刺激信号降调节 ,在母 胎免疫耐受的维持中发挥着重要作用。     

CTLA4Ig诱导细胞无能的作用机制探讨

IL 2受体α链 (又称CD2 5 )是T淋巴细胞活化的标志分子 ,CTLA4Ig所诱导的细胞无能CD2 5的表达下降。用FACS方法检测CTLA4Ig诱导的细胞无能的凋亡现象 ,结果发现未处理组与处理组间无差异 ;CTLA4Ig处理后的细胞无能Fas和FasL的表达 ,与未处理对照组无差异。用免疫印迹方法 ,检测发现CTLA4Ig诱导的细胞无能与未处理组相比P2 1Ras没有明显变化。用RT PCR方法检测一些细胞因子mRNA的表达水平 ,发现CTLA4Ig所诱导的细胞无能不能表达IL 2mRNA ,IFN γmR NA的表达下降 ,而IL 4mRNA、IL 10mRNA仍可表达 ,表明细胞无能的基因格局显示Th1基因受抑 ,有向Th2偏移倾向     

血红素加氧酶-1调节CD4~+T细胞亚群拮抗过敏性哮喘的实验研究

制备哮喘小鼠模型,干预血红素加氧酶-1(heme oxygenase-1,HO-1)表达,探讨HO-1在过敏性气道炎症中抗炎及其对T辅助细胞(T helper,Th)1、Th2、Th17和调节性T细胞(regulatory T cell,Treg)的调节作用。用卵清蛋白(ovalbumin,OVA)致敏、激发BALB/c小鼠制备以嗜酸性粒细胞(eosinophil,EOS)浸润为主的哮喘动物模型,并在致敏、激发中给予HO-1底物氯化高铁血红素(hemin)诱导HO-1高表达。经肺脏组织病理切片,血清OVA特异性IgE水平,肺泡灌洗液(bronchial alveolar lavage fluid,BALF)炎症细胞分类计数观察哮喘小鼠气道炎症程度;western blot和real-time PCR分别检测肺脏和脾脏组织HO-1基因表达和蛋白量,肺脏组织Th1、Th2、Th17及Treg分泌的细胞因子及特定转录因子基因表达;流式细胞术分析脾脏CD4+T细胞亚群。实验结果显示,OVA致敏、激发后(OVA组),小鼠肺脏和脾脏HO-1表达较正常组增高,血红素干预后(OVA+hemin组),HO-1蛋白表达则进一步升高;肺脏病理组织学显示OVA组见大量炎症细胞浸润,以EOS为主,伴BALF中细胞总数和EOS数及血清OVA特异性IgE增加,但经血红素干预后,上述现象明显减轻;OVA组肺组织中T-bet表达及IFN-γ水平降低;但GATA-3和RORγt表达及IL-4、IL-17A和IL-6水平较正常组显著增高,而血红素能逆转该结果;进一步显示OVA+hemin组Foxp3表达和IL-10及TGF-β水平较其余两组显著增高;脾脏CD4+T细胞亚群结果显示OVA组可见大量Th2,Th17略有增多,Th1和Treg则略降低,血红素干预明显下调Th2和Th17细胞比例,显著提升Treg细胞比例,而Th1则呈现升高趋势。结果表明,上调HO-1表达能显著拮抗EOS性气道炎症,该作用是通过调节Th17/Treg和Th1/Th2细胞平衡,促进TGF-β和IL-10分泌以抑制气道炎症。     

Ovalbumin-specific IgE modulates ovalbumin-specific T-cell response after repetitive oral antigen administration

BACKGROUND: Some patients outgrow their food allergies even though their serum antigen-specific IgE levels remain high. OBJECTIVE: To elucidate the role of T cells in outgrowing food allergies in the presence of antigen-specific IgE, we tracked antigen-specific T-cell responses after oral antigen administration. METHODS: Ovalbumin (OVA)-specific T-cell receptor (TCR) and OVA-specific IgE transgenic (Tg) mice (OVA-TCR/IgE-Tg) and OVA-specific TCR Tg (OVA-TCR-Tg) mice were fed with high doses of OVA or PBS every other day. After 7 administrations, OVA-specific proliferation and cytokine production of mononuclear cells of the spleen, mesenteric lymph nodes, and Peyer's patches and the number of splenic CD4 + CD25 + T cells were analyzed. RESULTS: Without OVA administration, the splenocytes from OVA-TCR/IgE-Tg mice exhibited a higher proliferative response and produced more IL-4 and IL-10 and less IFN-gamma than those from OVA-TCR-Tg mice. The proliferative responses of the splenocytes from either OVA-TCR/IgE-Tg mice or OVA-TCR-Tg mice fed with OVA were significantly reduced compared with those from PBS-fed mice. The number of OVA-specific TCR + T cells decreased in the spleen from OVA-fed mice, whereas the number of CD4 + CD25 + T cells increased. The suppressed proliferation of splenocytes of OVA-fed mice was partially resumed by neutralization of TGF-beta1, but not of IL-10. CONCLUSION: The presence of OVA-specific IgE modulated the OVA-specific responses of the splenocytes. Irrespective of the presence of OVA-specific IgE, repetitive oral administration of OVA induced tolerance, which seems to be composed of clonal deletion/anergy and TGF-beta1-mediated active suppression.     

Synthesized OVA323-339MAP octamers mitigate OVA-induced airway inflammation by regulating Foxp3 T regulatory cells

ABSTRACT: BACKGROUND: Antigen-specific immunotherapy (SIT) has been widely practiced in treating allergic diseases such as asthma. However, this therapy may induce a series of allergic adverse events during treatment. Peptide immunotherapy (PIT) was explored to overcome these disadvantages. We confirmed that multiple antigen peptides (MAPs) do not cause autoimmune responses, which led to the presumption that MAPs intervention could alleviate allergic airway inflammation without inducing adverse effects. RESULTS: In this study, synthesized OVA323-339MAP octamers were subcutaneously injected into ovalbumin (OVA)-sensitized and -challenged Balb/c mice to observe its effect on allergic airway inflammation, Th2 immune response, and immune regulating function. It was confirmed that OVA sensitization and challenge led to significant peritracheal inflammatory, cell infiltration, and intensive Th2 response. Treatment of OVA323-339MAP octomers in the airway inflammation mice model increased CD4+CD25+Foxp3+ T regulatory (Treg) cells and their regulatory function in peripheral blood, mediastinal draining lymph nodes, and the spleen. Furthermore, OVA323-339MAP increased IL-10 levels in bronchial alveolar lavage fluid (BALF); up-regulated the expression of IL-10,membrane-bound TGF-beta1, as well as Foxp3 in lung tissues; and up-regulated programmed death-1 (PD-1) and cytotoxic T lymphocyte associated antigen 4 (CTLA-4) on the surface of Treg cells. These results were further correlated with the decreased OVA specific immunoglobulin E (sIgE) level and the infiltration of inflammatory cells such as eosinophils and lymphocytes in BALF. However, OVA323-339 peptide monomers did not show any of the mentioned effects in the same animal model. CONCLUSIONS: Our study indicates that OVA323-339MAP had significant therapeutic effects on mice allergic airway inflammation by regulating the balance of Th1/Th2 response through Treg cells in vivo. Key words Allergic airway inflammation; Specific immunotherapy; Multiple antigen peptide.     

Opposite effects of immunotherapy with ovalbumin and the immunodominant T-cell epitope on airway eosinophilia and hyperresponsiveness in a murine model of allergic asthma.

In the present study, we investigated immunotherapy using an entire protein or an immunodominant epitope in a murine model of allergic asthma. Immunotherapy was performed in ovalbumin (OVA)-sensitized mice before OVA challenge. Mice were treated subcutaneously with OVA, the immunodominant epitope OVA323-339, or vehicle. In vehicle-treated animals, repeated OVA challenge induced increased serum levels of OVA-specific immunoglobulin (Ig)G1, IgE, airway eosinophilia, and hyperresponsiveness, compared with saline-challenged animals. In addition, interleukin (IL)-4 and IL-5 production upon OVA restimulation of lung-draining lymph node cells in vitro were significantly increased in OVA-challenged animals. Immunotherapy using OVA significantly reduced airway eosinophilia and hyperresponsiveness. This finding was accompanied by significantly reduced OVA-specific IL-4 and IL-5 production. Further, OVA immunotherapy induced increased serum levels of OVA-specific IgG1, whereas OVA-specific IgG2a and IgE levels were not affected. In contrast to OVA immunotherapy, immunotherapy with OVA323-339 aggravated airway eosinophilia and hyperresponsiveness. OVA-specific IgG1, IgG2a, and IgE serum levels, and in vitro IL-4 and IL-5 production, were not affected. Thus, immunotherapy with protein resulted in beneficial effects on airway eosinophilia and hyperresponsiveness, which coincided with a local reduced T-helper 2 (Th2) response. In contrast, peptide immunotherapy aggravated airway hyperresponsiveness and eosinophilia, indicating a local enhanced Th2 response.     

Female mice are more susceptible to the development of allergic airway inflammation than male mice

BACKGROUND: In humans the prevalence of asthma is higher among females than among males after puberty. The reason for this phenomenon is not clear. OBJECTIVE: We tested the hypothesis that female mice are more susceptible to the development of allergic asthma than male mice and studied allergic immune responses in the lung. METHODS: We compared allergic airway inflammation, i.e. methacholine (MCh) responsiveness, serum IgE, and cytokines, and the number of the different leucocytes in lungs of male and female BALB/c mice, twice-sensitized to ovalbumin (OVA) and subsequently challenged with OVA (OVA-mice) or phosphate-buffered saline (PBS-mice) aerosols on days 24-26, 30, and 31. RESULTS: OVA challenge significantly increased MCh responsiveness, numbers of eosinophils, CD4(+) T cells, CD4(+)/CD25(+) T cells, B cells, and levels of Thelper (Th)2 cytokines, total, and OVA-specific IgE. There was, however, also an effect of gender, with female mice responding to OVA challenges with higher numbers of eosinophils, CD4(+) T cells, B cells, and levels of IL-4, IL-13, IFN-gamma, total, and OVA-specific IgE than male mice. In contrast, female PBS-mice had significantly lower percentages of regulatory CD4(+)/CD25(+) T cells than males (females 4.2+/-0.2% vs. males 5.3+/-0.1% of CD4(+) T cells, P<0.05). CONCLUSION: Female mice develop a more pronounced type of allergic airway inflammation than male mice after OVA challenge. The reduced percentage of regulatory T cells in the lungs of female PBS-mice may indicate that the level of these cells in the lung during the sensitization phase is important for the development and/or progression of an allergic immune response after multiple OVA challenges.     

Interleukin-16 aggravates ovalbumin-induced allergic inflammation by enhancing Th2 and Th17 cytokine production in a mouse model

Asthma is a chronic inflammatory disease that involves a variety of cytokines and cells. Interleukin-16 (IL-16) is highly expressed during allergic airway inflammation and is involved in its development. However, its specific mechanism of action remains unclear. In the present study, we used an animal model of ovalbumin (OVA)-induced allergic asthma with mice harboring an IL-16 gene deletion to investigate the role of this cytokine in asthma, in addition to its underlying mechanism. Increased IL-16 expression was observed during OVA-induced asthma in C57BL/6J mice. However, when OVA was used to induce asthma in IL-16^−/− mice, a diminished inflammatory reaction, decreased bronchoalveolar lavage fluid (BALF) eosinophil numbers, and the suppression of OVA-specific IgE levels in the serum and BALF were observed. The results also demonstrated decreased levels of T helper type 2 (Th2) and Th17 cytokines upon OVA-induced asthma in IL-16^−/− mice. Hence, we confirmed that IL-16 enhances the lung allergic inflammatory response and suggest a mechanism possibly associated with the up-regulation of IgE and the promotion of Th2 and Th17 cytokine production. This work explored the mechanism underlying the regulation of IL-16 in asthma and provides a new target for the clinical treatment of asthma.     

CTLA4-IgG reverses asthma manifestations in a mild but not in a more "severe" ongoing murine model.

We investigated whether CTLA4-Ig can reverse established asthma manifestations in a novel murine model of ongoing disease. In BALB/c mice, sensitized to ovalbumin (OVA) without adjuvant, airway inflammation was induced by a first series of OVA aerosol challenges. Murine CTLA4-IgG was then administered, followed by a second series of OVA inhalations. In control-treated mice, two series of OVA challenges induced upregulation of OVA-specific IgE in serum, eosinophils in the bronchoalveolar lavage fluid (BALF), and IL-5 production by lung lymphocytes upon OVA restimulation in vitro, compared with saline-challenged mice. CTLA4-IgG significantly inhibited all of these parameters in OVA-challenged mice. Importantly, mCTLA4-IgG performed better than the gold-standard dexamethasone because this corticosteroid did not inhibit the upregulation of OVA-specific IgE in serum. In a more "severe" ongoing model, induced by sensitization to OVA emulsified in aluminum hydroxide, resulting in airway hyperresponsiveness to methacholine and stronger inflammatory responses, mCTLA4-IgG was less effective in that only the number of eosinophils in the BALF was reduced (P = 0.053), whereas dexamethasone inhibited both BALF eosinophilia and cytokine production by lung lymphocytes. Thus, CTLA4-Ig might be an effective alternative therapy in established allergic asthma, especially in situations of mild disease.     

DGKα DNA vaccine relieves airway allergic inflammation in asthma model possibly via induction of T cell anergy

Induction of T cell immune tolerance is thought to be a good method for treatment of asthma. Diacylglycerol kinases alpha (DGKα), enzymes that catalyze phosphorylation of diacylglycerol to produce phosphatidic acid, could inhibit diacylglycerol (DAG)-mediated signaling following T-cell receptor engagement and prevent T cell hyperactivation, thus playing important roles in the induction of T cell anergy. In the present study, we aimed to investigate the effects of DNA vaccine encoding DGKα gene administration on allergen-induced airway allergic inflammation in the murine model of asthma. Animal models were created and plasmid containing DGKα were constructed. Cytokine production was detected after the administration of DGKα gene plasmid. Immunization of mice with alum-adsorbed ovalbumin (OVA) followed by challenged with inhalation of aerosolized OVA resulted in the development of airway allergic inflammation. Administration of DGKα gene before the aerosolized OVA challenge significantly decreased the allergic airway inflammation and eosinophil infiltration in bronchoalveolar lavage fluid (BALF). Immunization with DGKα DNA vaccine decreased OVA-specific IgE and interleukin 13 (IL-13) levels in sera, and increased the IFN-γ level in BALF. The results of the present study provide evidence for the potential utility of the administration of DGKα DNA vaccine as an approach to gene therapy for asthma.     

Lipopolysaccharide inhalation exacerbates allergic airway inflammation by activating mast cells and promoting Th2 responses

BACKGROUND: Bacterial infection occasionally exacerbates asthma, although the cellular and molecular mechanisms have not been well defined. An involvement of mast cells has been suggested, as lipopolysaccharides (LPS)-induced cytokine production from mast cells in vitro. OBJECTIVE: This study was undertaken to examine the effects of LPS inhalation on mast cell functions and allergen-specific immune responses in a murine model of asthma. METHODS: Female BALB/c mice or mast cell-deficient W/W(v) mice were immunized intraperitoneally with ovalbumin (OVA). Mice were challenged with aerosolized OVA or OVA with LPS daily from day 21 to day 24. Twenty-four hours after the last challenge, airway inflammation and OVA-specific immune responses were examined. Allergen-specific T cell responses were further analysed by adoptively transferring OVA-specific CD4(+) T cells. Expression of chemokines in the lung was also examined. RESULTS: LPS inhalation with OVA resulted in exacerbated airway infiltration, which was not evident in mast cell-deficient mice. IL-5 production by mast cells in the lung was enhanced by LPS inhalation. OVA-specific IgE production as well as proliferation, cytokine production and local infiltration of OVA specific T-helper lymphocytes type 2 (Th2) were also enhanced. Up-regulated expression of Th2- and/or eosinophil-attracting chemokines was observed in the lung of mice inhalated with LPS. CONCLUSIONS: LPS inhalation exacerbates airway inflammation, which is accompanied by mast cell activation and enhanced Th2 responses. These observations provide clues towards understanding the mechanisms of bacterial infection-induced exacerbation of the clinical features of asthma.