PPD对TH1细胞的在体调节及对卵蛋白致敏小鼠气道炎症的影响

目的：探索结核菌素纯蛋白衍生物（purified protein derivative，PPD）对卵蛋白（ovalbumin，OVA）致敏小鼠肺组织TH1细胞的在体调节和对气道炎症的。方法：取37只Balb/c小鼠，雌雄兼有，6-8周。OVA雾化连续10d，每次雾化20min，复制OVA致敏模型。观察记录小鼠耗氧量、肺组织淋巴细胞反应和支气管肺泡灌洗液（bronchoalveolar lavage fluid，BALF）中炎性细胞变化。结果：OVA致敏组小鼠肺组织CD4^ T淋巴细胞增加，CD8^ T淋巴细胞无明显变化，主要表现为γ-IFN阴性CD4^ T淋巴细胞的增加，γ-IFN^ /CD4比较降低。PPD治疗后，肺组织CD4^ 淋巴细胞降低，但γ-IFN^ 细胞明显增加。OVA致敏小鼠消耗氧增加，PPD治疗后降低。结论：使用本实验体系PPD可上调TH1细胞并减轻实验性哮喘的气道反应。     

减毒活菌卡介苗通过STAT6对哮喘小鼠肺组织Th1和Th2型细胞因子的影响

目的:研究减毒活菌卡介苗(BCG)干预对哮喘小鼠呼吸道炎症、气管肺泡盥洗液(BALF)中细胞因子及肺组织信号转导和转录激活因子-6(STAT6)蛋白表达的影响。方法:将昆明小鼠30只随机分为正常对照组、哮喘组、BCG治疗组3组,每组小鼠都为10只。正常对照组以生理盐水致敏激发,以卵清白蛋白(OVA)致敏激发建立小鼠哮喘模型,BCG治疗组于OVA致敏前及后5天分别以BCG皮内注射干预,所有小鼠在最后一次抗原激发后24小时收集BALF,计数BALF中的白细胞总数及嗜酸性粒细胞(EOS)数目,苏木素-伊红(HE)染色观察小鼠肺组织病理形态学改变,用酶联免疫吸附试验(ELISA)检测BALF中IL-4、IFNγ-水平,以免疫组织化学法观察各组小鼠肺组织STAT6表达。结果:小鼠肺组织HE切片显示哮喘组有大量炎症细胞浸润。哮喘组、BCG治疗组小鼠肺组织STAT6蛋白表达和BALF中的白细胞总数、EOS计数、IL-4水平均较正常对照组升高(P<0.05);而与哮喘组比较,BCG治疗组肺组织STAT6蛋白表达和BALF中的白细胞总数、EOS计数、IL-4水平均降低(P<0.05)。与正常对照组比较,哮喘组BALF中的IFNγ-水平显著下降(P<0.01),而BCG治疗组BALF中的IFNγ-水平增加(P<0.05)。结论:BCG能抑制哮喘小鼠气道炎症、减少哮喘小鼠Th2型细胞因子IL-4的生成、提高Th1细胞因子IFNγ-的水平,其干预机制可能与BCG抑制哮喘小鼠肺组织STAT6蛋白的表达有关。     

呼吸道合胞病毒对致敏小鼠气道炎症和CD8+ T细胞功能的影响

目的观察呼吸道合胞病毒（RSV）对致敏小鼠气道炎症和CD8^＋T细胞功能的影响.方法BALB/c小鼠40只,随机分成4组,分别为磷酸盐缓冲液（PBS）对照组、鸡卵白蛋白（OVA）组、RSV组、OVA/RSV组;应用OVA腹腔注射致敏、OVA气道雾化结合RSV滴鼻激发哮喘;支气管肺泡灌洗液（BALF）作细胞分类计数;酶联免疫吸附试验（ELISA）测定BALF上清中白细胞介素（IL）-4、IL-5、干扰素（IFN）-γ含量;苏木精-依红（HE）染色观察肺病理变化;采用三色光流式细胞分析法测定气管旁淋巴结（PBLN）中CD4^＋、CD8^＋T细胞及细胞内细胞因子IFN-γ、IL-4、IL-5表达与TH2/TH1、Tc2/Tc1比值变化.结果（1）BALF中细胞总数及分类：与OVA组比较,OVA/RSV组细胞总数、嗜酸性粒细胞、淋巴细胞均明显增加（分别P＜0.01）;与RSV组比较,OVA/RSV组细胞总数、嗜酸性粒细胞明显增加（分别P＜0.01）.（2）BALF上清中细胞因子含量：与OVA组比较,OVA/RSV组IFN-γ、IL-4、IL-5含量均明显升高（分别P＜0.01）;与RSV组比较,OVA/RSV组IFN-γ无明显变化,而IL-4、IL-5显著上升（分别P＜0.01）.（3）肺组织病理：OVA/RSV组与其他各组比较气道黏膜增厚,管腔狭窄、收缩,上皮破坏,管壁周围炎症细胞浸润明显加重.（4）PBLN中CD4^＋（WN-γ^＋、IL-4^＋、IL-5^＋）、CD8^＋（IFN-γ^＋、IL-4^＋、IL-5^＋）T细胞各占CD3^＋T细胞百分比及TH2/TH1、Tc2/Tc1比值变化：与OVA组比较,OVA/RSV组CD8^＋（IFN-γ^＋、IL-4^＋、IL-05^＋）T细胞百分比、Tc2/Tc1比值增加（分别P＜0.01）,TH2/TH1比值无明显变化.与RSV组比较,OVA/RSV组CD4^＋（IL-4^＋、IL-5^＋）T细胞、TH2/TH1比值、CD8^＋（IL-4^＋、IL-5^＋）T细胞、Tc2/Tc1比值均明显上升（分别P＜0.01）.结论（1）OVA致敏小鼠RSV感染后可明显加重气道炎症,TH2、TH1型炎症均加强,且以TH2型炎症加重为主.（2）OVA致敏小鼠RSV感染后可引起CD8^＋T细胞数量及功能改变,即由产生IFN-γ^＋为特征的Tc1细胞向产生IL-4^＋、IL-5^＋为特征Tc2细胞转化,并可能与气道内IL-4、IL-5升高及嗜酸性粒细胞的大量募集有关.     

不同Th1/Th2细胞免疫应答支气管肺泡灌洗液中细胞学的变化

目的 探讨不同Th细胞优势应答下支气管肺泡灌洗液（BALF）中的细胞学变化，了解Th1/Th2细胞免疫应答的细胞和分子机制。方法 用鸡卵清蛋白（OVA）致敏Wistar大鼠（每组10只），制作致敏大鼠哮喘模型；用“冻干BCG”皮内注射制作BCG免疫大鼠模型。收集BALF并做HE染色，进行细胞分类计数。采用流式细胞术，测定BALF中，CD2^ ,CD28^ 及γδTCR^ T细胞占总淋巴细胞的百分率及平均荧光密度（MIF）。用原位杂交法，检测肺组织中IL－4mRNA的IFN－γmRNA的表达。用ELISA法检测血清IL－4和IFN－γ的浓度。结果 哮喘组BALF中淋巴细胞，嗜酸性粒细胞（EOS），浆细胞和中性粒细胞的总数，均显著多于正常组（P＜0．01）；BCG免疫组BALF中，淋巴细胞和巨噬细胞的总数也显著高于正常组（P＜0．001）。哮喘组BALF中，CD2^ T 细胞的明显增加。但哮喘组CD2^ T细胞的F1显著高于正常组及BCG组（P＜0．05）；BCG组BALF中，CD^2 T细胞的百分率与正常组相比产无显著差异（P＞0．05），其CD2^ T细胞的MFI显著高于正常组(P＜0．05）。哮喘组和BCG组BALF中，CD28^ 细胞占淋巴细胞的百分率显著多于正常组（P＜0．01）；BCG组CD28^ 细胞的MFI高于哮喘组（P＜0．01）。两组的CD28^ 细胞的MF1均显著多于正常组（P＜0．05）。哮喘组和BCG组BALF中，γδTCR^ 细胞占淋巴细胞的百分率显著高于正常组（P＜0．01）。结论 支气管哮喘患者Th2细胞的优势应答，与BALF中的B细胞，EOS，浆细胞和中性粒细胞等APC数的增加及T细胞上CD2的高表达有关；而BCG免疫组中的Th1细胞的优势应答与BALF中巨噬细胞，T细胞增加及T细胞上CD28的高表达有关。γδT细胞可能存在Th1/Th2细胞免疫模式，既参与哮喘免疫也参与BCG免疫过程，可能是调节Th0细胞分化的重要始动细胞。     

卡介苗对哮喘小鼠TH1/TH2平衡的影响

目的　探讨卡介苗 (BCG)对哮喘小鼠TH1 TH2平衡的影响。方法　C5 7BL 6小鼠以卵白蛋白 (OVA)致敏激发建立哮喘模型。于第一次抗原激发前 2周以BCG皮内注射干预 ,在最后 1次抗原激发后 4 8h收集支气管肺泡灌洗液 (BALF)和外周血 ,ELISA方法测定外周血清及BALF中IL 5与IFN γ水平 ,并采用三色光流式细胞分析法测定外周血TH1 TH2细胞比。结果　与阴性对照组相比 ,OVA致敏激发组外周血清及BALF中IL 5水平升高而IFN γ水平降低 ,BCG干预组外周血清及BALF中IL 5较OVA致敏激发组低而IFN γ较后者升高 ,与阴性对照组水平相近。此外 ,OVA致敏激发组外周血中TH2 TH1比值 (1.5 7± 0 .5 6 )较阴性对照组 (0 .37± 0 .0 5 )明显增高 (P <0 .0 1) ,BCG干预后TH2 TH1比值 (0 .5 9± 0 .11)较OVA致敏激发组下降 (P <0 .0 5 ) ,同时Tc2 Tc1比值 (0 .6 2± 0 .0 7)也较OVA致敏激发组 (1.15± 0 .18)降低 (P <0 .0 5 )。结论　哮喘小鼠中TH2型免疫应答占优势 ,BCG干预不仅在细胞因子水平 ,也在细胞数量上校正了TH1 TH2失平衡。     

苯亚甲基丙二腈脂类衍生物AG490减轻中性粒细胞性哮喘模型小鼠气道炎症

目的观察苯亚甲基丙二腈脂类衍生物AG490对中性粒细胞性哮喘模型小鼠气道炎症的影响。方法无特定病原体(SPF)级C57BL雌性小鼠54只,按随机数字表法分成中性粒细胞性哮喘(NA)组、AG490处理的NA(NAAG)组和正常(NC)组,每组18只。NA、NAAG组小鼠于第0、6、13天经气道滴卵清蛋白(OVA)、脂多糖(LPS)致敏。NAAG组小鼠于实验第0天起经腹腔注射AG490每只500μg,3次/周,连续3周。于第21天连续2 d雾化吸入10 g/L OVA激发,每次1 h。最后1次雾化结束后24 h时,收集小鼠标本并检测相关指标。收集支气管肺泡灌洗液(BALF)并检测其有核细胞总数及分类比例;分离肺组织行HE染色及过碘酸希夫(PAS)染色,光镜下观察肺组织病理变化和杯状细胞增生;采用流式细胞术检测肺脏Th17细胞和调节性T细胞(Treg)的频数;采用ELISA检测小鼠BALF中IL-17的水平。结果与NA组相比,NAAG组BALF有核细胞计数、中性粒细胞百分比、嗜酸性粒细胞百分比均明显降低,NAAG组肺组织病理学改变及杯状细胞增生较NA组明显减轻。与NA组相比,NAAG组BALF IL-17水平降低、肺组织Th17细胞比例减少、Treg比例增加。结论 NA小鼠致敏阶段给予AG490处理,可增加小鼠激发阶段肺组织Treg数量、减少Th17细胞数量,减轻NA小鼠气道炎症。     

新生期卡介苗和乙肝疫苗联合接种对哮喘小鼠IFN-γ、IL-4和IL-17A表达的影响

目的:观察新生期卡介苗(BCG)和乙肝疫苗(HepB)联合接种对哮喘小鼠干扰素γ(IFN-γ)、白细胞介素4(IL-4)和白细胞介素17A(IL-17A)表达的影响,探讨BCG和HepB联合接种对气道炎症的影响及可能机制。方法:BALB/c小鼠随机分为BCG和HepB联合接种造模[卵清蛋白(OVA)所致哮喘模型]组(B/H/O组)、BCG接种造模组(B/O组)、HepB接种造模组(H/O组)、BCG和HepB联合接种组(B/H组)、造模组(OVA组)、BCG组、HepB组和生理盐水对照(NS)组,每组6只。B/H/O组和B/H组于第0、7和14天分3次皮下注射1×105CFU的BCG,同时第0和28天分2次下肢腿部肌肉注射HepB 1.5μg,其它组单独接种BCG或HepB。OVA致敏和雾化吸入激发建立哮喘模型;末次激发24 h后取肺组织HE染色;收集支气管肺泡灌洗液(BALF)进行细胞总数计数和嗜酸性粒细胞(EOS)计数;ELISA法检测血清IFN-γ和IL-4及肺组织匀浆IL-17A的水平。结果:肺组织病理观察发现,OVA组、B/O组、B/H/O组和H/O组支气管周围大量炎症细胞浸润,气道上皮细胞增生肥大,B/H/O组和H/O组的炎症程度较OVA组重,B/O组则较OVA组轻。B/H/O组、B/O组和H/O组BALF细胞总数与OVA组比较均下降(P0.05);EOS计数在B/H/O组比B/H组上升(P0.05),B/O组比BCG组上升(P0.05),H/O组比HepB组上升(P0.05)。分别与H/O组、OVA组和NS组比较,HepB组的血清IFN-γ/IL-4比值均升高(P0.05);分别与B/H/O组、B/O组、OVA组和NS组比较,B/H组的血清IFN-γ/IL-4比值均升高(P0.05)。与OVA组比较,B/H/O组和B/O组的肺组织匀浆IL-17A水平均下降(P0.05);与B/O组比较,B/H/O组的肺组织匀浆IL-17A水平进一步下降(P0.05)。结论:卡介苗和乙肝疫苗联合接种有助于减轻哮喘模型小鼠肺部的炎症反应,其机制可能与降低IL-4分泌、提高IFN-γ/IL-4水平和抑制IL-17A的表达有关。     

肾怡对狼疮小鼠免疫器官内Th1/Th2细胞比例的调节作用

目的：探讨复方中药肾怡对MRL/lpr小鼠免疫器官内Th1/Th2细胞比例的调节作用。方法：将MRL/lpr狼疮小鼠随机分成对照组和中药治疗组，从12周观察到28周后于实验终点处死小鼠。通过流式细胞术分别检测胸腺和脾脏中CD4^ CD30^-(Th1)、CD4^ CD30^ (Th2)淋巴细胞所占百分比，进一步对脾细胞进行CD^ T淋巴细胞分选，并于体外利用PHA—P进行刺激后，通过RT—PCR方法检测IL-4(Th2细胞因子)和IFN—γ(Th1细胞因子)的表达丰度，比较二者的比值在对照组和中药治疗组之间的差别。结果：胸腺中几乎检测不到CD4^ CD30^ T淋巴细胞；脾脏中虽可检测到CD4^ CD30^ T淋巴细胞，但在未加入PHA-P的条件下，CD4^ CD30^ T淋巴细胞在对照组和中药治疗组中所占的比例没有显著差异；经PHAP刺激后对照组和治疗组脾细胞中CD4^ CD30^ T淋巴细胞所占百分比均明显增加，但治疗组中CD4^ CD30^ T淋巴细胞所占百分比的增加程度明显低于对照组；将脾细胞中CD4^ T淋巴细胞分选出来后进行RT-PCR检测，结果显示中药治疗组CD^ T淋巴细胞所表达IL-4／IFN—γ(Th2／Th1)比值明显低于对照组。结论：复方中药肾怡能够纠正MRL/lpr狼疮小鼠脾脏中CD^ T淋巴细胞在PHA-P刺激的条件下朝向Th2过度分化的倾向性。     

雾化吸入灭活草分支杆菌减轻哮喘小鼠气道炎症及对Toll样受体2表达的影响

目的研究雾化吸入灭活草分支杆菌对支气管哮喘小鼠气道炎症及肺组织细胞因子分泌的影响,探讨Toll样受体2(TLR2)表达在雾化吸入灭活草分支杆菌防治支气管哮喘中的作用。方法将24只雄性Balb/c小鼠按随机数字表法分为3组,每组8只:正常对照组(A)、哮喘模型组(B)、干预组(C)。卵清蛋白(OVA)致敏制小鼠支气管哮喘模型。C组在每次卵蛋白激发前给予雾化吸入草分枝杆菌治疗,每天1次。各组动物处死后提取肺组织和支气管肺泡灌洗液(BALF)。进行病理HE染色、AB-PAS染色观察支气管肺炎症和气道粘液分泌情况,并行半定量分析。BALF中炎症细胞计数,检测BALF中IL-4、IL-10、IFN-γ水平。实时定量PCR检测肺组织TLR2 mRNA表达水平。结果干预组BALF中IL-4分泌减少,IL-10、IFN-γ增加(P<0.05),BALF中嗜酸性粒细胞比例低于模型组,气道炎症病变较模型组减轻,肺组织TLR2 mRNA表达水平较模型组显著升高(P<0.05)。结论吸入草分枝杆菌能减轻支气管哮喘小鼠气道炎症,其效应与调节肺内细胞因子分泌有关。草分枝杆菌可能通过上调TLR2基因的表达调节支气管哮喘的免疫失衡。     

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     

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.     

Essential role of dendritic cell CD80/CD86 costimulation in the induction, but not reactivation, of TH2 effector responses in a mouse model of asthma

BACKGROUND: Airway dendritic cells (DCs) are crucial for the generation of TH2 cells from naive T cells during sensitization and for reactivation of primed TH2 cells on allergen challenge in mouse models of asthma. It is unknown whether CD80/CD86 costimulation is necessary during both phases of the response because primed T cells rely less on costimulatory molecules compared with naive T cells. OBJECTIVE: We sought to study the contribution of CD80/CD86 costimulatory molecules on DCs during sensitization or challenge in a mouse model of asthma. METHODS: Naive BALB/c mice received an intratracheal injection of ovalbumin (OVA)-pulsed DCs obtained from the bone marrow of wild-type (WT) or CD80/CD86-/- mice and were subsequently challenged with OVA aerosol to address the role of costimulation during sensitization. OVA-sensitized mice received OVA-pulsed WT or CD80/CD86-/- DCs without OVA aerosol to address the role of costimulation during challenge. RESULTS: WT DCs induced the proliferation and effector TH2 differentiation of naive OVA-specific T cells, whereas CD80/CD86-/- DCs induced only proliferation. Not surprisingly, WT DCs but not CD80/CD86-/- DCs induced sensitization to OVA in naive mice. In contrast, in OVA-sensitized mice intratracheal injection of CD80/CD86-/- OVA-pulsed DCs led to eosinophilic airway inflammation, goblet cell hyperplasia, and effector TH2 cytokine production that was not different from that seen after injection with WT OVA-DCs, even when the inducible costimulator ICOS was blocked or cytotoxic T lymphocyte-associated antigen 4 immunoglobulin was given. CONCLUSION: CD80/CD86 costimulation on DCs is only necessary during priming of naive T cells into TH2 cells but not during restimulation of previously primed TH2 cells in the challenge phase.     

Interleukin-10 gene transfer to the airway regulates allergic mucosal sensitization in mice.

The objective of this study was to investigate the effect of airway gene transfer of interleukin (IL)-10, a cytokine with potent anti-inflammatory and immunoregulatory activities, on allergic mucosal sensitization. We used a recently described murine model that involves repeated exposures to aerosolized ovalbumin (OVA), daily for 10 d, in the context of granulocyte macrophage colony-stimulating factor (GM-CSF) expression in the airway environment achieved by intranasal delivery of a replication-deficient adenovirus carrying the GM-CSF transgene. The resulting inflammatory response was characterized by a T-helper 2 cytokine profile and marked airway eosinophilia. After complete resolution of the inflammatory response (Day 28), a single exposure to OVA reconstituted airway eosinophilia and induced airway hyperresponsiveness. We show that concurrent expression of IL-10 inhibited GM-CSF-driven OVA-specific inflammation in a dose-dependent manner. Specifically, IL-10 decreased the number of mononuclear cells, neutrophils, and eosinophils in the bronchoalveolar lavage fluid (BALF). Histologic evaluation of the tissue corroborated the findings in the BALF. Concurrent expression of IL-10 at the time of mucosal sensitization abrogated both the cellular and physiologic recall responses in vivo. Studies in interferon (IFN)-gamma knockout mice demonstrated that prevention of airway eosinophilia by IL-10 was IFN-gamma-independent and that expression of IL-10 was associated with decreased levels of IL-4, IL-5, and tumor necrosis factor-alpha in the BALF. Flow cytometric analysis of dispersed lung cells showed that expression of IL-10 in the airway reduced the absolute number of Class II major histocompatibility complex (MHC)(+)/CD11c(+) (dendritic cells) and Class II MHC(+)/Mac-1(bright) (macrophages) cells expressing the costimulatory molecules B7.1 and B7.2 by 30%. However, IL-10 coexpression did not prevent expansion of CD4 and CD8 T cells or expression of the early activation marker CD69 on T cells. Thus, airway gene transfer of IL-10 altered the immune response to OVA in a way that resulted in inhibition of airway inflammation. These findings suggest that development of an immunoregulatory strategy based on IL-10, alone or in combination with GM-CSF, warrants further consideration.     

Regulation of allergen-induced bone marrow eosinophilopoiesis: role of CD4+ and CD8+ T cells

BACKGROUND: The mechanisms of the distant stimulation of the bone marrow (BM) after airway allergen exposure remain largely obscure. T cells have been implicated in allergic airway inflammation but their role in allergen-induced BM eosinophilopoiesis is poorly understood. The aim of this study was to determine the role of CD4(+) and CD8(+) T cells in allergen-induced BM eosinophilopoiesis. METHODS: Ovalbumin (OVA)-sensitized wild type (WT), CD4 knockout (CD4-/-) and CD8 knockout (CD8-/-) mice were exposed intranasally to OVA or saline. Bromo-deoxyuridine (BrdU) was used to label newly produced cells. Bone marrow, blood and bronchoalveolar lavage (BAL) were sampled 24 h after the final exposure. Immunostaining for newly produced eosinophils (i.e. BrdU(+)/MBP(+)) and BM eosinophil progenitor [CD34(+)/CD45(+)/interleukin-5 (IL-5)Ralpha(+)] cells was performed. RESULTS: The number of newly produced BM eosinophils (BrdU(+)/MBP(+) cells) was significantly reduced in allergen exposed CD4-/- or CD8-/- mice compared with allergen exposed WT mice, which was followed by a subsequent decrease in newly produced blood and airway eosinophils. Furthermore, BM eosinophil progenitors were significantly reduced in allergen exposed CD4-/- and CD8-/- mice compared with WT mice. Finally, serum IL-5 and Bronchoalveolar lavage fluid eotaxin-2 levels were abolished in allergen exposed CD4-/- mice to levels seen in saline exposed WT mice. CONCLUSIONS: These data suggests that both CD4(+) and CD8(+) T cells have a regulatory role in allergen-induced BM eosinophilopoiesis, whereas CD4(+) T cells are obligatory for allergen-induced airway eosinophilia. The subsequent traffic of eosinophils to the airways is likely to be at least partly regulated by a CD4(+) T-cell-dependent local airway eotaxin-2 production.     

Virally activated CD8 T cells home to Mycobacterium bovis BCG-induced granulomas but enhance antimycobacterial protection only in immunodeficient mice

The effect of secondary infections on CD4 T-cell-regulated chronic granulomatous inflammation is not well understood. Here, we have investigated the effect of an acute viral infection on the cellular composition and bacterial protection in Mycobacterium bovis strain bacille Calmette-Guérin (BCG)-induced granulomas using an immunocompetent and a partially immunodeficient murine model. Acute lymphocytic choriomeningitis virus (LCMV) coinfection of C57BL/6 mice led to substantial accumulation of gamma interferon (IFN-gamma)-producing LCMV-specific T cells in liver granulomas and increased local IFN-gamma. Despite traffic of activated T cells that resulted in a CD8 T-cell-dominated granuloma, the BCG liver organ load was unaltered from control levels. In OT-1 T-cell-receptor (TCR) transgenic mice, ovalbumin (OVA) immunization or LCMV coinfection of BCG-infected mice induced CD8 T-cell-dominated granulomas containing large numbers of non-BCG-specific activated T cells. The higher baseline BCG organ load in this CD8 TCR transgenic animal allowed us to demonstrate that OVA immunization and LCMV coinfection increased anti-BCG protection. The bacterial load remained substantially higher than in mice with a more complete TCR repertoire. Overall, the present study suggests that peripherally activated CD8 T cells can be recruited to chronic inflammatory sites, but their contribution to protective immunity is limited to conditions of underlying immunodeficiency.     

Differential capacity of CD8α+ or CD8α− dendritic cell subsets to prime for eosinophilic airway inflammation in the T-helper type 2-prone milieu of the lung

BACKGROUND: Different subsets of dendritic cells (DCs), identified in mouse spleen by their differential expression of CD8 alpha, can induce different T-helper (Th) responses after systemic administration. CD8 alpha(-) DCs have been shown to preferentially induce Th type 2 (Th2) responses whereas CD8 alpha(+) DCs induce Th1 responses. OBJECTIVE: To study if these DC subsets can still induce different Th responses in the Th2-prone milieu of the lung and differentially prime for eosinophilic airway inflammation, typical of asthma. METHODS: Donor mice first received daily Flt3L injections to expand DC numbers. Purified CD8 alpha(+) or CD8 alpha(-) splenic DCs were pulsed with ovalbumin (OVA) or phosphate-buffered saline and injected intratracheally into recipient mice in which carboxyfluorescein diacetate succinimidyl ester-labelled OVA-specific T cell receptor transgenic T cells had been injected intravenously 2 days earlier. T cell proliferation and cytokine production of Ag-specific T cells were evaluated in the mediastinal lymph nodes (MLNs) 4 days later. The capacity of both subsets of DCs, to prime for eosinophilic airway inflammation was determined by challenging the mice with OVA aerosol 10 days later. RESULTS: CD8 alpha(-) DCs migrated to the MLN and induced a vigorous proliferative T cell response accompanied by high-level production of IL-4, IL-5, IL-10 and also IFN-gamma during the primary response and during challenge with aerosol, leading to eosinophilic airway inflammation. In the absence of migration to the MLN, CD8 alpha(+) DCs still induced a proliferative response with identical levels of IFN-gamma but reduced Th2 cytokines compared with CD8 alpha(-) DCs, which led to weak eosinophilic airway inflammation upon OVA aerosol challenge. Unpulsed DCs did not induce proliferation or cytokine production in Ag-specific T cells. CONCLUSION: CD8 alpha(-) DCs are superior compared with CD8 alpha(+) DCs in inducing Th2 responses and eosinophilic airway inflammation in the Th2-prone environment of the lung.     

Oral administration of Enterococcus faecalis FK-23 suppresses Th17 cell development and attenuates allergic airway responses in mice

Evidence is increasing that oral administration of probiotics can attenuate asthmatic responses both in murine models and clinical trials. T-helper 17 (Th17) cells, a subset of CD4+ T cells have been implicated as having an important role in the development of several allergic disorders, but the relationship between oral administration of probiotics and Th17 development has not been well studied. BALB/c mice were given lysed Enterococcus faecalis FK-23 (LFK) orally for 28 days. After sensitization by subcutaneous injection of ovalbumin (OVA) on Days 14 and 21 and 1% OVA inhalation on Days 25, 26 and 27, they were challenged with a 5% OVA aerosol on Day 28. Twenty-four hours later, airway resistance and accumulation of inflammatory cells in bronchoalveolar lavage fluid (BALF) and lung tissues were determined. Ιnterleukin (IL)-17-expressing CD4+ lymphocytes isolated from lung, spleen and lamina propria of the intestine were detected by flow cytometry. The expression of IL-6 and TGF-β mRNA was assessed by real-time PCR. Increases in airway hyperresponsiveness, and numbers of total leukocytes and mast cells in BALF induced by OVA challenge were significantly suppressed by oral administration of LFK. The increased percentage of IL-17-expressing CD4+ cells from lung, spleen and intestine in OVA-challenged mice was reduced following LFK treatment. We conclude that the oral administration of LFK suppresses the asthmatic response and that this is associated with attenuation of Th17 cell development.     

Allergic sensitization and allergen exposure during pregnancy favor the development of atopy in the neonate

BACKGROUND: Several studies have considered that the in utero environment plays an important role in the onset of the allergic phenotype. We assessed whether allergic sensitization and allergen exposure during pregnancy favor the postnatal onset of allergy in the neonate. METHODS: BALB/c mice were sensitized to ovalbumin (OVA) before mating followed by allergen aerosol exposure during pregnancy. T and B cell responses in offspring were followed up until day 60 postpartum. At the age of 4 weeks offspring were exposed to a heterologous antigen, beta-lactoglobulin (BLG). RESULTS: Pregnant mice developed immediate hypersensitivity responses and Th-2/ Th-0 immunity following allergen aerosol exposure. At birth, T cells from offspring of nonsensitized BALB/c mice were characterized by an impaired IFN-gamma production, which was lowered even further in offspring of OVA-sensitized BALB/c mice. Offspring of OVA-sensitized BALB/c mice responded with immediate-type cutaneous hypersensitivity reactions to OVA which could be related to the pre- and postnatal transfer of maternal OVA-specific IgG1 antibodies. After exposure to BLG, offspring of OVA-sensitized BALB/c mice developed an accelerated Th-2-driven immune response compared to offspring from nonsensitized BALB/c mice as indicated by enhanced anti-BLG IgG1 antibody production and increased numbers of positive immediate-type cutaneous hypersensitivity reactions to BLG. CONCLUSION: Our data suggest that Th-2/Th-0 immunity present during pregnancy has a decisive impact on shaping the Th-1/Th-2 T cell profile in response to postnatal allergen exposure.