发酵乳杆菌干预对牛乳β-乳球蛋白过敏小鼠模型的免疫调节作用

目的观察活的/热致死发酵乳杆菌对牛乳β-乳球蛋白(BLG)致敏小鼠Th1/Th2细胞平衡、血清抗体水平及T淋巴细胞亚群数量的影响,探讨其缓解过敏反应的作用。方法用牛乳BLG和弗氏佐剂的混合液腹腔注射诱发Balb/c小鼠致敏,建立动物过敏模型。将实验动物随机分为空白组、致敏组、活的与热致死发酵乳杆菌组。采用ELISA法测定各组小鼠血清总IgE和BLG特异性IgE含量。体外分离培养各组小鼠脾淋巴细胞,采用ELISA法检测细胞上清液中Thl型细胞因子(IL-12、IFN-γ)和Th2型细胞因子(IL-4)的水平,采用流式细胞术检测脾淋巴细胞中CD3+、CD4+和CD8+的百分含量。结果与致敏组相比,活的/热致死发酵乳杆菌组小鼠的IFN-γ/IL-4比值(代表Thl/Th2细胞平衡)显著增高(P<0.05);血清总IgE和BLG特异性IgE水平显著降低(P<0.05);脾淋巴细胞中的CD4+细胞比例升高,CD4+/CD8+比值得到优化。特别是热致死的发酵乳杆菌组抑制IL-4分泌的效果显著优于活菌组(P>0.05),且该组的抗体水平和CD4+/CD8+比值与空白组相比无差异(P>0.05)。结论发酵乳杆菌干预可改善小鼠的BLG过敏症状,其作用可能与促进Thl占优势的Thl/Th2细胞平衡,阻断IgE分泌及平衡T淋巴细胞亚群数量相关。     

细粒棘球绦虫重组Bb-Eg95-EgA31融合蛋白诱导小鼠免疫应答

目的研究细粒棘球绦虫(Eg)重组双歧杆菌(Bb)-Eg95-EgA31融合蛋白免疫小鼠后诱导的免疫应答。方法 56只SPF级雌性Balb/c小鼠随机均分7组,分别为重组Bb-Eg95-EgA31皮下注射组(A组)、肌肉注射组(B组)、鼻腔内接种组(C组)、口服灌胃组(D组)、空载体对照组(E组)、Bb对照组(F组)和Bb培养用液体培养基(MRS)对照组(G组)。免疫后8周各组鼠用50个Eg原头节攻击,攻击25周后,处死小鼠,分离细粒棘球蚴包囊并称重,计算囊重抑制率;ELISA检测血清IgG及其亚类和IgE和脾细胞上清液IL-12、IFN-γ、TNF-α和IL-10水平;MTT法测定脾细胞增殖反应;流式细胞仪检测脾CD4+和CD8+T细胞百分比和脾细胞凋亡发生率。结果重组Bb-Eg95-EgA31免疫组小鼠的囊重抑制率分别为45.33%、41.33%、70.67%和62.67%;血清IgG、IgG2a、IgG2b和IgG1水平升高,IgG3和IgE降低;脾IFN-γ、IL-12和TNF-α水平升高,IL-10水平降低;脾T淋巴细胞明显增殖;脾CD4+和CD8+T细胞显著增加;脾细胞凋亡发生率显著降低。结论细粒棘...     

乳杆菌对原代淋巴细胞中Th1/Th2细胞平衡的影响

目的:分析7种乳杆菌对原代淋巴细胞增殖和细胞因子(CK)分泌的作用,进而探讨其对Th1/Th2细胞平衡的影响。方法:用不同种属、不同浓度的活的/热致死的乳杆菌体外作用于小鼠脾淋巴细胞培养60 h后,采用MTT比色法检测淋巴细胞的增殖效果。用ELISA法检测Th1型细胞因子(IL-12、IFN-γ)、Th2型细胞因子(IL-4、IL-10)和调节型细胞因子(TGF-β)的分泌量。结果:活的/热致死的乳杆菌单独作用,就能促进淋巴细胞体外增殖并表现出剂量依赖关系(P<0.05)。当菌的浓度为107集落形成单位(CFU)/mL(即细菌与细胞的比例为10∶1)时,热致死的发酵乳杆菌和嗜酸乳杆菌的免疫活性近似于活菌。而且,这两株热致死菌还可适当提高淋巴细胞分泌IL-12和IFN-γ,抑制IL-4、IL-10和TGF-β的分泌,使其IFN-γ/IL-4的比值(代表Th1/Th2细胞平衡)均显著高于刀豆蛋白A(ConA)对照组(P<0.05)。结论:乳杆菌可通过提高淋巴细胞的IFN-γ/IL-4分泌率来促进Th1优势状态的Th1/Th2细胞平衡,并具有菌株特异性。     

细粒棘球绦虫重组Bb-Eg95-EgA31疫苗诱导小鼠免疫应答的动态观察

目的:观察细粒棘球绦虫(Eg)重组双歧杆菌(Bb)-Eg95-EgA31疫苗免疫小鼠后其免疫应答的动态变化。方法:将疫苗分别采用口服灌胃和鼻腔内接种免疫BALB/c鼠,分别于免疫后2、4、6、8、10、12、14、16、18和20周用ELISA法测定免疫小鼠血清中IgG及其亚类和IgE水平。用MTT法测定脾淋巴细胞的增殖,用ELISA法检测脾淋巴细胞培养上清液中IL-12、IFN-γ、TNF-α和IL-10水平,用流式细胞术(FCM)检测脾CD4+和CD8+T细胞百分率。结果:口服免疫小鼠血清IgG、IgG2a、IgG2b、IgG1、IgG3和IgE水平分别在免疫后8、2、6、6、8和10周达到峰值。脾淋巴细胞悬液中IL-12、IFN-γ、TNF-α和IL-10水平分别在免疫后4、2、4和6周达到峰值。脾淋巴细胞增殖在免疫后6周达到峰值;脾CD4+T细胞在免疫后6周达到峰值,脾CD8+T细胞无明显变化。鼻腔内接种免疫小鼠血清IgG、IgG2a、IgG2b、IgG1、IgG3和IgE水平分别在免疫后10、6、10、8、8和10周达到峰值。脾淋巴细胞悬液中IL-12、IFN-γ、TNF-α和IL-10水平分别在免疫后2、2、4和8周达到峰值。脾淋巴细胞增殖在免疫后6周达到峰值;脾CD4+T细胞在免疫后6周达到峰值,脾CD8+T细胞无明显变化。口服免疫和鼻腔内接种是两种较好的免疫途径,且前者优于后者。结论:细粒棘球绦虫重组Bb-Eg95-EgA31疫苗可诱导小鼠产生有效的免疫应答。     

细粒棘球绦虫转Eg95-EgA31融合基因苜蓿疫苗诱导Balb/c小鼠免疫应答的动态观察

目的动态观察细粒棘球绦虫转Eg95-EgA31融合基因苜蓿疫苗免疫Balb/c小鼠后诱导的免疫应答。方法热絮凝法提取转基因苜蓿的叶蛋白,再用无菌双蒸水将叶蛋白提取液的浓度配制成20μg/μl。88只Balb/c小鼠随机分为2组,分别用100μl灌胃和10μl滴鼻免疫小鼠,每3天1次,连续免疫2个月。在末次免疫后0、2、4、6、8、10、12、14、16、18和20周各组随机剖杀4只小鼠,眼球取血,常规酶联免疫吸附法(enzyme-linked immunosorbent assay,ELISA)检测血清中IgG及其亚类和IgE水平;取脾,分离脾细胞,流式细胞仪(flow cytometr,FCM)检测脾CD4+和CD8+T淋巴细胞亚群的百分比,体外经脾细胞悬液或加入Eg粗抗原(EgAg)、伴刀豆球蛋白A(ConA)或脂多糖(LPS)刺激培养,四甲基偶氮唑盐比色法(MTT法)检测免疫鼠脾T淋巴细胞增殖情况,ELISA法检测脾细胞培养上清液中IL-12、IL-10、IFN-γ和TNF-α水平。结果在末次免疫后4～6周,2组免疫小鼠的血清IgG及其亚类和IgE水平升高,脾T淋巴细胞增殖水平升高,CD4+和CD8+T细胞亚群百分比分别升高,脾细胞培养上清液中IL-12、IFN-γ、TNF-α和IL-10水平分别升高。结论细粒棘球绦虫转Eg95-EgA31融合基因苜蓿疫苗在免疫早期(4～6周)可诱导免疫鼠脾T淋巴细胞增殖,产生Th1和Th2混合型免疫应答,CD4+和CD8+T细胞亚群在细粒棘球绦虫转Eg95-EgA31融合基因苜蓿疫苗诱导的保护性免疫机制中起重要作用。     

细粒棘球绦虫转Eg95-EgA31融合基因苜蓿疫苗诱导小鼠免疫应答的研究

目的:探讨细粒棘球绦虫(Eg)转Eg95-EgA31融合基因苜蓿疫苗诱导BALB/c小鼠产生的免疫应答及其对Eg原头节攻击感染的保护性作用。方法:热絮凝法提取转基因苜蓿的叶蛋白,再用无菌双蒸水将叶蛋白提取液的浓度配制成20g/L。分别用100μL灌胃和10μL滴鼻免疫小鼠,每3d免疫1次,连续免疫2个月。同时设转空质粒(pBI121)苜蓿叶蛋白及正常苜蓿叶蛋白对照组。末次免疫后8周,用Eg原头节腹腔注射进行攻击感染(50个Eg原头节/每鼠),感染后24周剖杀小鼠,分离并称重细粒棘球蚴组织,计算囊重减少率;采眼球血,常规ELISA检测血清中IgG及其亚类和IgE水平;取脾,分离脾细胞,流式细胞术(FCM)检测脾CD4+和CD8+T淋巴细胞亚群的百分比;脾细胞体外经脾细胞悬液或加入Eg粗抗原(EgAg)、伴刀豆球蛋白A(ConA)或脂多糖(LPS)刺激培养后,四甲基偶氮唑盐比色法(MTT法)检测免疫小鼠脾T淋巴细胞增殖情况,AnnexinV-FITC和碘化丙啶(PI)双染色法检测脾细胞的凋亡发生率,常规ELISA法检测脾细胞培养上清液中IL-12、IL-10、IFN-γ和TNF-α水平。结果:与正常蛋白对照组相比,疫苗口服接种组小鼠检获包囊质量明显降低,囊重减少率为64.1%,脾细胞凋亡发生率明显降低,脾T细胞增殖水平、CD4+T细胞亚群的百分比和CD4+/CD8+比值显著升高,血清中IgG、IgG2b和IgE水平显著升高,脾细胞培养上清液中IFN-γ、1L-12和TNF-α水平显著增高,IL-10水平明显降低。结论:细粒棘球绦虫转Eg95-EgA31融合基因苜蓿疫苗口服接种可抑制免疫鼠脾细胞发生凋亡,诱导免疫鼠脾T细胞增殖,产生Th1型细胞免疫应答以对抗Eg原头节的攻击感染,CD4+ T细胞亚群、IgG、IgG2b和IgE在疫苗诱导的保护力中起重要作用。     

日本血吸虫重组Bb(pGEX-Sj14-3-3)疫苗免疫BALB/c小鼠诱导免疫应答的动态检测

目的 研究日本血吸虫重组双歧杆菌属两歧双歧杆菌(Bb) (pGEX-Sjl4-3-3)疫苗免疫小鼠后其免疫应答的动态变化.方法 将重组疫苗分别采用口服灌胃和鼻内接种免疫BALB/c小鼠,分别于免疫后2、4、6、8、10、12、14、16、18、20和22周ELISA法测小鼠血清中IgG及其亚类、IgE和IgA及脾细胞培养液中IFN-γ、IL-12、TNF-α和IL-10水平;MTT法测定脾细胞增殖;流式细胞仪检测脾细胞凋亡率及CD4+和CD8+T细胞亚群百分率.结果 口服组血清IgG、IgG1、IgG2a、IgG2b、IgG3、IgE和IgA水平分别在免疫后8、6、6、4、8、10和6周达峰值.脾淋巴细胞增殖和凋亡水平均在免疫后4周达峰值;CD4+T细胞于8周达峰值,CD8+T细胞于14周达峰值.IFN-γ、IL-12、TNF-α和IL-10水平分别于8、8、6和4周达峰值.鼻内接种组血清IgG、IgG1、IgG2a、IgG2b、IgG3、IgE和IgA分别于4、6、4、4、8、10和8周达峰值.脾淋巴细胞增殖及凋亡水平也均在4周达峰值;CD4+T细胞于8周达峰值,CD8+T细胞于4周达峰值.IFN-γ、IL-12、TNF-α和IL-10水平分别于2、2、4和4周达峰值.口服及鼻腔内接种是两种较好的免疫途径,且后者优于前者.结论 该疫苗可诱导小鼠产生有效的免疫应答.     

PcDNA3.0/p27~(kip1)真核表达质粒对小鼠哮喘模型Th1/Th2的影响

目的:探讨细胞周期负性调控蛋白PcDNA3.0/p27kip1重组真核表达质粒转染小鼠哮喘模型对Th1/Th2比例失衡的调节作用。方法:小鼠各10只分为A组(正常对照组)、B组(哮喘模型组)、C组(质粒治疗组)三组。用卵蛋白致敏法构建小鼠哮喘模型,以本实验室构建的PcDNA3.0/p27kip1重组真核表达质粒经静脉转染小鼠哮喘模型,36小时后Western blot检测肺组织中p27蛋白表达量;流式细胞仪分析小鼠脾CD4+、CD8+T细胞比例;ELISA检测小鼠血清IL-4、IL-5、IL-13、IFN-γ水平。结果:B组与A组比较,哮喘发病后肺p27蛋白表达量明显降低;脾CD4+T细胞显著增高而CD8+T细胞显著降低;血清IL-4、IL-5、IL-13水平明显升高而IFN-γ明显降低。C组与B组比较,肺p27蛋白表达量明显增加,脾CD4+T细胞比例显著降低而CD8+T细胞显著升高;血清IL-4、IL-5、IL-13水平明显降低而IFN-γ明显升高。结论:PcDNA3.0/p27kip1静脉给药可在哮喘模型肺组织中表达,并通过基因干预调控细胞周期的方式调节Th1/Th2比例失衡,为哮喘防治提出了新思路。     

一种以虾原肌球蛋白为致敏原的Th2 反应小鼠模型的建立

目的:采用虾原肌球蛋白为致敏原建立Th2 反应小鼠模型。方法:虾原肌球蛋白腹腔注射小鼠6 周诱导Th2反应,ELISA 测定小鼠血清总IgE、sIgE 和sIgG 水平、脾淋巴细胞分泌Th1 和Th2 细胞因子的含量,采用流式细胞术检测血液中嗜碱性粒细胞的活化。结果:与对照组比较,致敏6 周的小鼠血清总IgE、sIgE 和sIgG(sIgG1、sIgG2a 和sIgG2b)均显著升高;脾淋巴细胞在抗原刺激后分泌Th2 细胞因子(IL-4、IL-5、IL-10 和IL-13)增加,而Th1 细胞因子INF-α则出现明显降低;血液中嗜碱性粒细胞表面标志物CD200R 和CD41 表达增强。结论:成功建立一种以虾原肌球蛋白为致敏原的Th2 反应小鼠模型。     

口服乳酸菌对尘螨致敏小鼠脾细胞的免疫调节作用

目的探讨口服乳酸菌对尘螨致变应性气道炎症小鼠脾细胞免疫调节功能的影响。方法雌性C57BL/6小鼠分为对照组(N组),尘螨组(M组),尘螨+乳酸乳球菌组(L组)和尘螨+植物乳杆菌组(P组)。脾细胞分离培养,检测培养上清IL-4、IL-5、IFN-γ和IL-10水平(ELISA法),脾细胞增殖情况(Brd U法),流式细胞术检测分泌IL-4/IFN-γ的CD3+CD4+细胞比例。结果在基础状态下,L组和P组脾细胞合成释放IL-4、IL-5及IFN-γ水平均明显低于M组,同时IL-10生成显著增加(P<0.05),以L组更明显。螨刺激下,L组脾细胞IL-4、IL-5的释放率要明显低于M组(P<0.05),IL-10的释放率则明显高于其余3组(P<0.05);细胞增殖试验示L组与P组细胞Brd U掺入量明显低于M组(P<0.001),与N组无差异;流式细胞术显示L组和P组,分泌IL-4的CD4+细胞减少的同时(23.1%&23.7%),总CD4+细胞比例反而增高(51.6%&43.9%),以L组为明显。结论口服乳酸菌诱导了小鼠脾细胞CD4+调节性T细胞亚群的增殖,主要通过释放IL-10下调Th1/Th2细胞因子水平,进而抑制了尘螨致变应性气道炎症。     

支原体肺炎患儿免疫球蛋白、T淋巴细胞亚群细胞因子检测的临床意义

目的:观察支原体肺炎(MPP)患儿外周血免疫球蛋白、T淋巴细胞亚群以及细胞因子的含量变化,并探讨其在MPP发病机制中的作用。方法:采用流式细胞技术检测43例MPP患儿和30例正常对照组儿童外周血T淋巴细胞亚群CD3+、CD4+、CD8+,并用速率散射比浊法检测血清IgG、IgA和IgM含量,采用ELISA检测血清干扰素-γ(IFN-γ)、白介素(IL-2、IL-4和IL-6)水平。结果:MPP患儿外周血CD3+、CD4+T细胞百分率分别为61.45±6.75和33.52±5.81,较正常对照组68.28±7.34和38.71±6.29显著降低(P<0.05),CD8+T细胞和CD4+/CD8+比值较对照组无显著差别(P>0.05);MPP患儿血清免疫球蛋白与正常对照组比较,IgG和IgA均无明显差异,IgM较对照组增高(P<0.05);MPP患儿IFN-γ、IL-4、IL-6血清水平以及IFN-γ/IL-4比值较正常对照组明显增高(P<0.05),而IL-2水平低于正常对照组(P<0.05)。结论:MPP患儿存在免疫功能减低,免疫调节紊乱,辅助性T细胞亚群(Thl/Th2)失衡,并以Thl型细胞介导的免疫反应占相对优势状态。     

IL-17作为分子佐剂增强HIV DNA疫苗细胞免疫应答的研究

目的 为了进一步增强HIV DNA疫苗的免疫反应,本研究将IL-17作为HIV DNA疫苗的分子佐剂免疫小鼠,旨在探讨IL-17对HIVDNA疫苗诱导体液和细胞免疫应答的影响.方法 将小鼠IL-17构建到真核表达载体,与HW-1膜蛋白DNA疫苗pGX-Env联合免疫BALB/c小鼠;分别在第0、2周进行免疫,在第4周检测T淋巴细胞增殖指数、抗-Env IgG、细胞因子表达水平和体内细胞毒性T淋巴细胞杀伤作用(CTL)等免疫学指标.结果 IL-17能够增强HIV DNA疫苗的特定免疫反应.与单注射疫苗组相比,IL-17作为佐剂组的T细胞增殖、抗体水平和CD4~+T细胞分泌IFN-γ、IL-4和IL-17的表达均无明显增强,但对CD8~+T细胞分泌IFN-γ的表达和体内CTL的效果影响明显(P<0.05).结论 IL-17作为分子佐剂不足以影响Th细胞分化,然而却能够增强特异性CD8~+T细胞中IFN-γ的表达,尤其是增强体内CTL反应.此结果为增强艾滋病DNA疫苗CD8~+T细胞活性和用于艾滋病的治疗提供了一个新的思路.     

Selective suppression of antigen-specific Th2 cells by continuous micro-dose oral tolerance

The effect on antigen (Ag)-specific Th2 response as well as IgE production of continuous oral administration of micro-doses of Ag was investigated. Transgenic (Tg) mice carrying the α β-T cell receptor (TCR) genes specific for ovalbumin (OVA) peptide fragment 323 – 339 were continuously fed with micro-doses of OVA (100 μg/day) for 14 days. Mice were first immunized by OVA in alum and pertussis toxin 7 days before the oral feeding and given a second immunization 1 day after the oral treatment. This feeding regimen tolerized Th2 but not Th1 responses as shown by decrease of Ag-driven cell proliferation and cytokine secretion of IL- 4 but not of IL-2 or IFN-γ as well as by the absence of Ag-specific antibody production of IgE and IgG1, but not of IgG2a or total IgG. Numbers of clonotype-specific TCR-high CD4-positive T cells in peripheral lymphoid tissues markedly decreased in the orally treated group but not in the control group. However, total numbers of CD4-positive T cells in thymus, spleen and lymph nodes were not affected by the oral treatment, indicating that tolerance induction in Th2 cells was mainly due to the down-regulation of TCR and not clonal deletion. The population of antigen-presenting cells expressing B7-2 (CD86) Ag on the surface was decreased in the spleen of the mice which underwent the feeding regimen. The present results suggest that Ag-specific low responsiveness in Th2 cells, which resulted in suppres sion of the Ag-specific IgE production, can be achieved by continuous feeding with microdoses of Ag.     

Roles of CD4+ and CD8+ T cells in adjuvant activity of diesel exhaust particles in mice

Through an imbalance in Th1 and Th2 cytokine profiles, diesel exhaust particles (DEP) are thought to induce Th2-dominated IgE and IgG1 production. However, the roles of CD4+ and CD8+ T-cell subtypes in the increased immune responses to antigen in mice exposed to DEP are unclear. In the present study, we investigated whether treatment with anti-CD4 or anti-CD8 mAb abrogated the adjuvant activity of DEP. On day -1 and day 1, each group of mice was injected intraperitoneally with anti-CD4, anti-CD8, or rat IgG (vehicle). On day 0, the mice were immunized with ovalbumin (OVA) or OVA plus DEP. After 3 weeks, each mouse was boosted with 10 microg of OVA alone. On day 7 after the first injection with OVA+DEP or OVA alone, the numbers of total, IA+, CD80+/IA+ and CD86+/IA+ cells in peritoneal exudate cells (PEC) were higher in OVA+DEP-immunized mice than in OVA-immunized mice. Depletion of CD8+ cells resulted in a modulation of the production of granulocyte-macrophage colony-stimulating factor, IL-12 and PGE(2) in peritoneal exudate fluid from OVA+DEP-immunized mice. On day 28, DEP injection markedly increased IL-4 production in the culture supernatants of spleen cells from CD4+ or CD8+-depleted mice. Depletion of CD8+ cells in OVA+DEP-immunized mice resulted in a decrease in IFN-gamma production compared with that in OVA-immunized mice. Adjuvant activity of DEP was observed in anti-OVA IgE, anti-OVA IgG1, anti-OVA IgG3, and total IgE production. Depletion of CD4+ T cells abrogated the adjuvant effect of DEP on anti-OVA IgE, and anti-OVA IgG1 production in plasma. However, depletion of CD8+ T cell inhibited the upregulated anti-OVA IgG3 production. These findings suggest that DEP injection may affect not only the function of CD4+ cells but also that of CD8+ T-cell subsets to modulate the synthesis of proinflammatory cytokine in PEC and type-1 and type-2 cytokine production in spleens.     

Lactobacillus casei strain Shirota suppresses serum immunoglobulin E and immunoglobulin G1 responses and systemic anaphylaxis in a food allergy model

BACKGROUND: Our previous study using allergen-sensitized murine splenocyte cultures has shown that Lactobacillus casei strain Shirota (LcS), a lactic acid bacterium widely used as a starter for fermented milk products, suppresses IgE production through promoting a dominant Th1-type response mediated by IL-12 induction. OBJECTIVE: We tried to evaluate the ability of LcS to suppress both IgE response and allergic reactions in vivo using a food allergy model with ovalbumin-specific T cell receptor transgenic (OVA-TCR-Tg) mice. METHODS: The ability of heat-killed LcS to induce IL-12 in serum was tested. OVA-TCR-Tg mice were fed a diet containing OVA for 4 weeks and injected with LcS intraperitoneally three times in the first week of this period. Cytokine and antibody secretion by splenocytes, and serum IgE and IgG1 responses were examined. The inhibitory effect of LcS on systemic anaphylaxis induced by intravenous challenge of OVA-fed OVA-TCR-Tg mice with OVA was also tested. RESULTS: Intraperitoneal injection of LcS induced an IL-12 response in the serum of OVA-TCR-Tg mice. In the food allergy model, LcS administration skewed the pattern of cytokine production by splenocytes toward Th1 dominance, and suppressed IgE and IgG1 secretion by splenocytes. The ability of LcS to modulate cytokine production was blocked by anti-IL-12 antibody treatment. LcS also inhibited serum OVA-specific IgE and IgG1 responses and diminished systemic anaphylaxis. CONCLUSION: LcS administration suppresses IgE and IgG1 responses and systemic allergic reactions in a food allergy model, suggesting a possible use of this lactic acid bacterium in preventing food allergy.     

In vivo administration of IL-18 can induce IgE production through Th2 cytokine induction and up-regulation of CD40 ligand (CD154) expression on CD4+ T cells

IL-18 is considered to be a strong cofactor for CD4+ T helper 1 (Th1) cell induction. We have recently reported that IL-18 can induce IL-13 production in both NK cells and T cells in synergy with IL-2 but not IL-12, suggesting IL-18 can induce Th1 and Th2 cytokines when accompanied by the appropriate first signals for T cells. We have now found that IL-18 can act as a cofactor to induce IL-4, IL-10 and IL-13 as well as IFN-gamma production in T cells in the presence of anti-CD3 monoclonal antibodies (mAb). IL-18 can rapidly induce CD40 ligand (CD154) mRNA and surface expression on CD4+ but not CD8+ T cells. The administration of IL-18 alone in vivo significantly increased serum IgE levels in C57BL/6 (B6) and B6 IL-4 knockout mice. Furthermore, the administration of IL-18 plus IL-2 induced approximately 70-fold and 10-fold higher serum levels of IgE and IgG1 than seen in control B6 mice, respectively. IgE and IgG1 induction in B6 mice by administration of IL-18 plus IL-2 was eliminated by the pretreatment of mice with anti-CD4 or anti-CD154, but not anti-CD8 or anti-NK1.1 mAb. These results suggest that IL-18 can induce Th2 cytokines and CD154 expression, and can contribute to CD4+ T cell-dependent, IL-4-independent IgE production.     

Lymphocytes in Peyer patches regulate clinical tolerance in a murine model of food allergy

BACKGROUND: Food allergy can lead to severe, potentially life-threatening anaphylactic reactions. To generate efficient strategies aimed at an active cure, a better understanding of the pathogenic mechanisms is strongly needed. OBJECTIVE: To investigate T-cell-related mechanisms of food allergy and tolerance to beta-lactoglobulin (BLG) in gut-associated lymphoid structures. METHODS: Beta-lactoglobulin-specific IgG1, IgG2a, and IgE in serum from mice anaphylactic to BLG were analyzed by ELISA and compared with those obtained in mice actively tolerized to BLG. The number of Ab-secreting cells in the spleen and in Peyer patches was determined by ELISPOT. The numbers of cytokine-producing cells after antigen-specific activation were measured by the same method. Furthermore, mesenteric lymph node cells and Peyer patches cells were transferred to naive mice, and Ab production as well as Ab-secreting cells were measured. RESULTS: Serum IgG1 and IgE Ab titers as well as IL-4-producing cell numbers were strongly increased in anaphylactic mice. IL-10 was found in Peyer patch cells from tolerant mice after BLG activation but not in anaphylactic mice. Peyer patch cells, in contrast to mesenteric lymph node cells, proliferated weakly in anaphylactic mice after antigen activation, and activation of Peyer patches was partially inhibited by tolerization. CONCLUSIONS: Our data suggest a specific role for lymphocytes in Peyer patches in tolerance to BLG. Low IL-10 production in Peyer patches may favor symptoms of food allergy.     

The role of interleukin-10 in the generation of CD4+ and CD8+ memory T cells (expressing a CD44+, CD62L- phenotype) and their contribution to the regulation of immunoglobulin E antibody formation

BACKGROUND: Immunization of mice with low doses of protein antigens like keyhole limpet hemocyanin (KLH) results in high immunoglobulin (Ig) E Ab titers in the sera of those mice while the application of high doses leads to the production of only marginal amounts of IgE but high levels of IgG2a and IgG1 antibodies. The aim of these studies is to elucidate the role of interleukin-10 (IL-10) in the generation of memory T cells and their contribution to the production of IgE Ab. METHODS: Both IL-10-deficient mice and control mice were immunized repeatedly with KLH. Serum levels of KLH-specific Ab were measured. The frequencies of memory T cells were determined by flow cytometry and the role of CD4+ and CD8+ T cells was evaluated. RESULTS: IL-10-deficient mice show an augmented production of IgE in vivo. They exhibit enhanced ratios of CD4+:CD8+ memory T cells with a CD44+, CD62L- phenotype with a significantly raised generation of CD4+ memory T cells. On the other hand, the development of CD8+ memory T cells is reduced moderately in IL-10-deficient mice, which is an interesting fact since it has been shown that primed CD8+ T cells suppress IgE Ab production at least in vitro. The ratios of total CD4+:CD8+ T cells are augmented in IL-10-deficient mice compared to wild-type mice and in K01 mice compared to K100 mice in vivo. CONCLUSIONS: The elevated ratios of CD4+:CD8+ T cells indicate a higher capacity to provide B cell help, which results in a strongly elevated IgE response in IL-10-deficient mice. These altered ratios are furthermore interesting in view of the regulatory role of CD8+ T cells which provide a suppressive potential regarding IgE Ab production as shown in vitro. The capacity of IL-10 to suppress IgE Ab production by reduction of the CD4+:CD8+ memory T cell ratio opens new possibilities in the interference with allergic disorders.