肺癌患者调节性T细胞的变化及CpG ODN的干预作用

目的:观察肺癌患者外周血调节性T细胞的变化,并探讨CpG ODN的干预作用。方法:分离肺癌患者和健康志愿者(各30例)的外周血单个核细胞(PBMC),用流式细胞仪检测CD4+CD25+调节性T细胞比例,Real-time PCR检测Foxp3基因的表达,ELISA法检测TGF-β和IFN-γ水平。将30例肺癌患者的PBMC随机分为实验组和安慰剂组,分别给予CpG ODN2006或安慰剂CpG ODN1612干预,比较干预前后上述指标的变化。结果:肺癌患者PBMC中的CD4+CD25+调节性T细胞比例、Foxp3基因的相对表达量、TGF-β水平均高于健康对照组,差异具有显著性,但不同病理分型和分期的肺癌患者亚组间比较无显著性差异。两组的IFN-γ水平比较无差异性。CpG ODN干预后CpG ODN2006治疗组的CD4+CD25+调节性T细胞比例、Foxp3基因的相对表达量及TGF-β水平出现了下降,差异有显著性,IFN-γ水平变化无显著性差异。而CpG ODN1612安慰剂组的上述指标在干预前后则无显著性改变。结论:肺癌患者外周血中的CD4+CD25+Foxp3+调节性T细胞比例、TGF-β水平明显升高。CpG ODN2006干预可下调CD4+CD25+Foxp3+调节性T细胞比例及TGF-β水平。     

CpG ODN抑制EB病毒复制的体外研究

目的:探讨CpG寡脱氧核苷酸链(CpG ODN)体外对EB病毒(EBV)复制的抑制作用.方法:CpG ODN体外预处理人外周血单个核细胞(PBMC)后感染EBV,用荧光定量PCR和ELISA分别检测培养后PBMC中EBV拷贝数和培养上清液中γ干扰素(IFN-γ)的水平,了解不同剂量、不同时间CpG ODN预处理PBMC中EBV复制和PBMC产生IFN-γ之间的关系.结果:(1)不同浓度CpG ODN预处理组的EBV拷贝数均低于未处理组( P <0.05),其中10 mg/L CpG ODN预处理组EBV拷贝数最低,为(3.85±0.37)×10 8基因拷贝/L;(2)CpG ODN预处理48 h组的EBV拷贝数(11.32±0.83)×10 8基因拷贝/L低于其余各预处理时间组的EBV拷贝数( P<0.05);(3)不同浓度CpG ODN预处理组培养上清液中的IFN-γ均高于PBMC组和PBMC+EBV组( P <0.05),其中 10 mg/L CpG ODN处理组IFN-γ量最高(66.27±6.29)ng/L;(4)CpG ODN预处理48 h的PBMC+CpG ODN+EBV组培养上清液中IFN-γ(51.74±4.09)ng/L高于其余各预处理时间组和PBMC组及PBMC+EBV组( P <0.05).结论:CpG ODN作为一种新型的免疫调节剂,在体外能有效抑制EBV复制,其作用机制可能与诱导PBMC产生IFN-γ有关.     

CpG ODN佐剂促进HBsAg疫苗诱导小鼠细胞免疫应答的探讨

目的 探讨cpG ODN对重组乙型肝炎表面抗原（HBsAg）诱导小鼠细胞免疫应答的影响。方法HBsAg和HBsAg＋CpG ODN分别肌肉注射免疫Balb／c小鼠后，从淋巴组织（脾和淋巴结）和非淋巴组织（肺）分离淋巴细胞，体外经HBsAg抗原刺激后，利用ELISA检测细胞培养液中IFN-γ的水平，再利用流式细胞仪在单个细胞水平上检测IFN-γ^＋细胞的频率，分析IFN-7^＋细胞亚群。结果对照组和HBsAg免疫组IFN-γ产生的水平很低，当HBsAg加强免疫1～2次后，IFN-γ表达仍然没有明显升高；而CpG ODN＋HBsAg免疫1次或加强免疫后，CpG显著促进HBsAg诱导的IFN-γ产生。进一研究结果表明CpG促进HBsAg诱导淋巴器官和非淋巴器官内CD4^＋和CD8^＋T细胞IFN-γ的表达。结论CpG免疫佐剂不仅能诱导细胞免疫应答同时也诱导体液免疫应答，提示CpG ODN可以用于HBsAg预防和治疗性佐剂。     

慢性乙肝病毒感染者不同免疫阶段IFN-γ斑点水平及其在低丙氨酸氨基转移酶抗病毒治疗中的作用

目的 探讨ELISPOT(Enzyme-linked immuno-spot assay,酶联免疫斑点检测)技术检测IFN-γ斑点数在评价慢性乙肝感染者免疫状态和指导慢性乙肝患者抗病毒治疗的应用价值.方法 将入选的慢性乙肝感染者(低水平丙氨酸氨基转移酶组17例、免疫耐受组14例、免疫清除组16例)和正常对照组15例研究对象分离PMBC(Peripheral blood mononuclear cell,外周血单个核细胞),用HBsAg刺激物与实验对象的PBMC细胞孵育,采用ELISPOT检测慢性乙肝感染者IFN-γ斑点水平,同时对17例低水平ALT(Manine aminotransferase,丙氨酸氨基转移酶)组行肝穿刺病理检查,分析其IFN-γ斑点水平与肝脏病理炎症分级的相关性;其中9例肝穿病理结果≥G2/S2并接受抗病毒治疗的慢性乙肝感染者3个月后再次采用ELISPOT检测IFN-γ斑点水平.结果 HBsAg刺激PBMC产生IFN-γ斑点水平在各组分别为免疫清除组117 ±53、低ALT组15 ±2、免疫耐受组13 ±2)和正常对照组59±10,除低ALT组与免疫耐受组之间无显著性差异外(P =0.85 ＞0.05),其余均有显著性差异.免疫清除组的慢性乙肝感染者中,HBsAg刺激物的IFN-γ斑点水平与血清ALT有显著相关性(r=0.976,P＜0.05).肝病理穿刺中17例低水平ALT慢性乙肝感染者,其中肝组织病理分期≥G2/S2的共9例,占52.9％;同时其IFN-γ斑点水平与肝脏炎症分级有显著相关性(r=0.630,P=0.009).9例肝穿病理结果≥G2/S2并接受抗病毒治疗的慢性乙肝感染者抗病毒治疗前后IFN-γ斑点水平有统计学差异(P=0.01).结论 慢性乙肝感染者免疫清除组IFN-γ斑点水平最高,低水平ALT的慢性乙肝感染者肝穿刺病理结果提示有很大一部分达到抗病毒指征,且其IFN-γ斑点水平与肝脏炎症程度呈正相关,通过ELISPOT检测IFN-γ斑点水平,可更好地判断慢性乙肝感染者免疫状态和评估慢性乙肝感染者抗病毒治疗效果.     

丙型肝炎病毒非结构区5个细胞毒性T细胞表位的鉴定

目的 采用T细胞表位预测软件结合体外实验鉴定丙型肝炎病毒(HCV)特异性细胞毒性T细胞(CTL)表位.方法 采用T表位预测软件Rankpep预测HCV特异性CTL表位,选择候选CTL表位加以合成;用候选CTL表位肽分别刺激HCV感染者以及健康志愿者的外周血单个核细胞(PBMC),采用酶联免疫斑点试验(ELISPOT)检测PBMC中肽特异性分泌IFN-γ的斑点形成细胞(spots forming cells,SFC)的水平,采用细胞内细胞因子染色(intracellular cytokine staining,ICS)检测PBMC中肽特异性IFN-γ+CD8+T细胞的水平.结果 用5条候选CTL表位肽[NS3 450(TVPQDAVSR)、NS3 594(GPTPLLYRL)、NS4b 78(SMMAFSAAL)、NS5a 416(SEENVSVVF)和NS5a 367(TVSSALAEL)]分别刺激10个HCV感染者和2个健康者的PBMC后,健康者的PBMC不产生IFN-γ而7个HCV感染者的PBMC产生IFN-γ;HCV感染者的PBMC中肽特异性分泌IFN-γ的细胞的频率为(5-36)SFC/105 PBMC,肽特异性IFN-γ+CD8+T细胞占总CD8+T细胞的百分比为0.02%～0.25%.结论 ELISPOT结果和ICS结果证实5条肽NS3 450、NS3 594、NS4b 78、NSSa 416和NS5a 367为全新的HCV特异性CTL表位.     

慢性乙型肝炎病毒感染者外周血T细胞γ干扰素和白细胞介素4的水平变化

目的研究慢性乙型肝炎病毒(HBV)感染过程中外周血T细胞表达细胞因子的调节作用。方法 60例慢性HBV感染者分为免疫耐受期组、免疫清除期组和非活动期组,20例健康人群作为对照组。另收集21例乙型肝炎病毒e抗原(HBe Ag)阳性的慢性乙型肝炎患者,进行恩替卡韦治疗6个月。全自动生化分析仪检测血清丙氨酸氨基转移酶(ALT)水平,PCR法检测HBV DNA载量,流式细胞术检测T细胞γ干扰素(IFN-γ)和白细胞介素4(IL-4)水平。结果慢性HBV感染者的外周血CD4~+T细胞和CD8~+T细胞的IFN-γ水平与HBV DNA载量呈反比,IFN-γ/IL-4比率与HBV DNA载量和血清ALT水平均呈反比。此外,从免疫耐受期到非活动病毒携带期,T细胞的IFN-γ水平逐渐增加、IL-4水平逐渐降低,且与对照组相比,免疫耐受期患者的T细胞表达IL-4增加且IFN-γ减少,到非活动携带期其细胞因子表达逐渐恢复。慢性乙型肝炎患者经恩替卡韦抗病毒治疗后,血清HBV DNA载量和ALT水平均明显降低,同时其外周血CD8~+T细胞的IFN-γ水平及IFN-γ/IL-4比率均明显增加。结论慢性HBV感染过程中,外周血T细胞的IFN-γ和IL-4发挥双向调节作用,与恩替卡韦抗病毒疗效相关。     

活动期结核病患者外周血NK细胞免疫反应特征分析

为了探讨自然杀伤(nature killer,NK)细胞在抗结核免疫应答中的特征,我们表达并纯化结核分枝杆菌特异性抗原蛋白ESAT-6,体外刺激结核病患者和正常人外周血单个核细胞(PBMC),采用流式细胞术分析不同亚群NK细胞IFN-γ释放,并与T细胞释放IFN-γ水平进行相关性分析。结果显示,经结核特异性抗原ESAT-6刺激后,结核患者来源的PBMC中有2.80%±0.65%的NK细胞可以释放IFN-γ,而正常人NK细胞释放的比例仅为0.09%±0.01%,两者间有显著差异(P0.001);同时CD56highCD16dim NK亚群细胞分泌IFN-γ的水平(6.50%±0.94%)显著高于CD56dimCD16high NK亚群细胞(1.78%±0.38%);比较同一抗原刺激条件下T细胞释放IFN-γ的能力,显示NK细胞释放IFN-γ的能力高于CD4+T和CD8+T细胞,并与释放IFN-γ的CD4+T细胞的比例呈显著正相关。上述研究结果表明,NK细胞在结核特异性抗原ESAT-6刺激下可通过分泌高水平的IFN-γ协同CD4+T细胞在抗结核感染中发挥重要作用,增强NK细胞的功能,以提高结核病患者的免疫应答水平,将为结核病的治疗提供新的策略。     

绿脓杆菌制剂与IL-12在诱导人NK细胞IFN-γ产生中的协同作用

探讨绿脓杆菌制剂(piliated Pseudomonas Aeruginosa,PPA)与IL-12协同诱导人PBMC和NK细胞IFN-γ的产生。分离健康人PBMC和纯化NK细胞分别与培养液、PPA、IL-12或PPA+IL-12共同培养,利用酶联免疫吸附法(ELISA)检测无细胞培养上清中IFN-γ的水平。同时采用流式细胞仪在单个细胞水平上分析PPA和IL-12诱导IFN-γ产生的淋巴细胞亚群。结果显示,单独应用亚适剂量的IL-12或PPA刺激人PBMC或纯化NK细胞,不能诱导或只能诱导低水平IFN-γ的产生。当PPA和IL-12共同与人PBMC或纯化NK细胞孵育后,PPA呈时间和剂量依赖性与IL-12协同诱导PBMC和纯化NK细胞产生大量IFN-γ。细胞亚群分析的结果表明,PPA和IL-12协同诱导CD56+NK细胞产生IFN-γ,但对CD4+T和CD8+T细胞无明显作用。PPA与IL-12协同促进NK细胞IFN-γ的产生,提示PPA和IL-12能直接刺激NK细胞发生免疫应答。     

Toll样配体(R-848)与IL-12对人NK细胞亚群IFN-γ产生的作用

目的:研究Toll样配体(R-848)与IL-12对人NK细胞IFN-γ产生的作用和细胞亚群分析。方法:分离人外周血PBMC和纯化的NK细胞,分别与R-848、IL-12或R-848和IL-12共同培养。利用ELISA法检测培养上清中IFN-γ的水平,再利用流式检测并分析产生IFN-γ的NK细胞亚群。结果:正常人PBMC分别与不同浓度的Toll样配体R-848、LPS、CpG培养后,均以剂量依赖的方式诱导IFN-γ的产生,但以R-848的效果最佳。细胞亚群分析的结果表明,R-848对CD4 T和CD8 T细胞IFN-γ的表达无明显作用,但显著地促进CD56 细胞表达IFN-γ。同样地,在IL-12刺激之下,CD56bright和CD56dimNK细胞表达IFN-γ。当R-848和IL-12与PBMC和纯化NK细胞孵育后,对CD56bright和CD56dimNK细胞IFN-γ的表达具有协同作用。结论:Toll样配体与NK细胞Toll样受体结合后,促进CD56brightNK细胞亚群IFN-γ的产生,而且Toll样配体与IL-12具有协同作用,提示Toll样受体与细胞因子在调控NK细胞的生物活性中发挥着十分重要的作用。     

骨髓间充质干细胞对异体T细胞几种细胞因子分泌的影响

目的:探讨骨髓间充质干细胞(MSC)对异体T淋巴细胞分泌IL-2、IL-4、IL-10、IFN-γ的影响,从而进一步探讨MSC诱导免疫耐受的机制。方法:将培养了3代后的MSC经照射后作为基底层细胞,接种分离的异体T淋巴细胞。共培养7天后,用ELASA方法检测上清中的上述四种细胞因子的蛋白含量,同时计数T淋巴细胞数量的变化,应用流式细胞仪检测与MSC共孵育前后T淋巴细胞CD3、CD4、CD8、CD25的变化。结果:(1)ELASA检测IFN-γ分泌量为667·07±14·76pg/ml;IL-10为46·19±1·41pg/ml;IL-2为33·01±5·92pg/ml;IL-4为0·15pg/ml。(2)共孵育组T淋巴细胞在数量上明显减少。(3)CD8+细胞数增多,CD25+细胞减少。结论:骨髓MSC在体外与异体T淋巴细胞共孵育后IFN-γ高分泌,可能与共孵育后T淋巴细胞亚群的改变有关。这一研究结果为预防HLA不相合的骨髓移植的GVHD的发生提供了一条新的思路。     

不同种类乙型肝炎表面抗原诱导小鼠早期细胞免疫应答的比较

目的 比较不同表达系统来源的乙型肝炎(乙肝)表面抗原(HBsAg)免疫小鼠诱导早期脾淋巴细胞抗原特异性细胞免疫应答的特点,探讨影响乙肝疫苗保护效果的因素.方法 3种HBsAg(汉逊酵母、CHO细胞和血源)分别皮下接种不同组小鼠(BALB/c,H-2d),每只3μg,于免疫后4d分离脾单个核细胞(MNC),经细胞分选仪(MACs)分选后,获得纯度高于90％的CD4+和CD8+T细胞,应用ELISPOT测定MNC、CD4+和CD8+T细胞体外刺激后所产生的细胞因子IFN-γ、IL-2斑点数( SFC).结果 细胞分选后,汉逊抗原诱导CD8+T细胞分泌IFN-γ的水平和CD4+T细胞分泌IL-2水平均显著高于CHO抗原组(8/10、2/10,P=0.035;6/10、0/10,P=0.005).汉逊抗原组与血源抗原组CD8+T细胞经体外刺激诱导IFN-y全部阳转(10/10),但分泌水平上汉逊抗原组显著高于血源抗原组(t=2.479,P=0.035);汉逊抗原组诱导CD4+T细胞IFN-γ阳转率及分泌水平均显著高于血源抗原组(10/10、4/10,P=0.005;t=3.967,P=0.003).结论 乙肝抗原免疫小鼠4d即可诱导细胞免疫应答,且汉逊酵母抗原早期诱导抗原特异性IFN-γ、IL-2的能力显著高于CHO和血源抗原,与其临床考核母婴传播阻断HBV保护率显著优于CHO和血源乙肝疫苗相一致,为及时接种乙肝疫苗的必要性和高危新生儿选择接种乙肝疫苗的类型提供依据.     

Identification of CpG oligonucleotide sequences with high induction of IFN-alpha/beta in plasmacytoid dendritic cells.

The immature plasmacytoid dendritic cell (PDC) is identical with the principal type I IFN-producing cell upon viral infection. Oligodeoxynucleotides which contain unmethylated CpG motifs (CpG ODN) are recognized by the vertebrate immune system. Previously, we described CpG ODN that strongly activate human B cells and human blood dendritic cells. Here we describe distinct CpG-containing oligonucleotide sequences which, in contrast to previously described CpG ODN, induced high amounts of IFN-alpha and IFN-beta in peripheral blood mononuclear cells (PBMC). Intracellular staining for IFN-alpha revealed that within PBMC CpG ODN-induced IFN-alpha is produced exclusively by PDC. Unlike IFN-alpha, TNF-alpha is up-regulated in PDC by all CpG ODN tested. Purified PDC responded to CpG ODN, demonstrating direct activation of PDC by CpG ODN. The most active sequence induced the production of up to 5 pg IFN-alpha per single PDC, resulting in more than 400 ng/ml IFN-alpha in the supernatant of PBMC enriched for PDC. The potency of CpG ODN to stimulate IFN-alpha correlated with their ability to stimulate NK cell lytic activity, while purified NK cells did not respond to CpG ODN. IFNgamma production in PBMC was dependent on CpG ODN-induced IFN-alpha/beta as demonstrated by IFN-alpha/beta blocking antibodies. IFN-alpha-inducing CpG ODN strongly supported IFN-gamma production of TCR-triggered CD4 T cells but were less active than other CpG ODN in stimulating B cells. In conclusion our results demonstrate that particular CpG ODN sequences exist which, due to high IFN-alpha/beta induction in PDC, induce a set of immune responses typical for viral infection.     

人参皂甙Rg3抗小鼠Lewis肺癌的机制研究

目的以小鼠Lewis肺癌为肿瘤模型探讨人参皂甙Rg3抗肿瘤机制。方法以肺癌细胞系LLC荷瘤C57/BL小鼠建立小鼠肺癌模型,随机分为人参皂甙Rg3组、阳性药顺铂组和模型组,分别给予人参皂甙Rg3、顺铂和生理盐水;同时设立空白对照组。以肿瘤质量、抑瘤率观察人参皂甙Rg3的抗肿瘤效果;以流式细胞术测定脾脏CD4+T细胞、CD8+T细胞数量及比值;以Elispot技术检测机体肿瘤抗原特异性CTL的诱生情况;以肝脏指数、脾脏指数、胸腺指数判定人参皂甙Rg3的毒副作用。结果人参皂甙Rg3组抑瘤率高于顺铂组,差异具有统计学意义(P<0.05)。生理盐水组小鼠脾脏CD4+T细胞、CD8+T细胞百分率比正常小鼠低,而人参皂甙Rg3组和顺铂组高于生理盐水组,差异具有统计学意义(P<0.05)。人参皂甙Rg3组肿瘤特异性IFN-γ斑点数明显增多,与生理盐水组相比具有统计学差异(P<0.05),顺铂组脾脏无肿瘤特异性IFN-γ斑点出现。和模型组相比较,人参皂甙Rg3组小鼠肝脏、脾脏、胸腺指数无明显差异,而顺铂组的肝脏、脾脏、胸腺指数低于人参皂甙Rg3组,差异具有统计学意义(P<0.05)。结论 LLC细胞荷瘤小鼠具有明显的免疫抑制现象,人参皂甙Rg3可显著增加脾脏CD4+T细胞、CD8+T细胞阳性率并促进肿瘤特异性CTL细胞诱生,人参皂甙Rg3无肝脏、胸腺、脾脏毒性。     

灭活与减毒两种甲肝疫苗免疫后诱导细胞免疫应答初探

目的 对国内普遍应用的减毒和灭活甲肝疫苗诱导的细胞免疫水平(产生时间、应答水平)进行检测和比较.方法 筛选健康志愿者18人,随机分组后分别接种甲肝减毒活疫苗和甲肝灭活疫苗.按实验程序以周次为时间点采血,用化学发光法对特异性甲肝抗体(HAY-IgG)进行检测;同时收集外周血单个核细胞(PBMC),用特异性甲肝抗原刺激后,以酶联免疫斑点试验(ELISPOT)法检测效应T细胞分泌TH1型细胞因子IFN-γ的情况;用胞内细胞因子染色法测定CD+ T和CD8+T淋巴细胞中分泌IFN-γ的阳性细胞百分比,Lumlnex法检测细胞培养上清中IFN-γ、IL-2、IL-10、IL-4等多种细胞因子水平.结果 两种疫苗均可诱导产生特异性抗HAV抗体,且观测期间抗体水平差异无统计学意义.两种疫苗接种初期即可诱导产生病毒特异性T细胞免疫应答反应,同时伴随高水平的效应细胞因子IFN-γ产生.在免疫接种后1-3周,灭活疫苗诱导的细胞免疫应答水平高于减毒疫苗;而在4-6周,减毒疫苗诱导的细胞免疫应答水平明显增高,超过灭活疫苗.灭活疫苗所诱导的细胞免疫应答在加强免疫后明显增强.结论 两种疫苗接种初期均可诱导体液和细胞免疫应答;灭活疫苗加强免疫后可激发记忆性免疫应答.     

Distinct CpG oligonucleotide sequences activate human gamma delta T cells via interferon-alpha/-beta.

Oligodeoxynucleotides with CpG motifs (CpG ODN) mimic microbial DNA and activate effectors of innate immunity including NK cells. Human gamma delta T cells (Vgamma9/Vdelta2) are antigen specific "natural memory" T cells in a preactivated stage, which respond to common non-protein phosphoantigens. Among several CpG ODN tested, distinct CpG ODN sequences characterized by inducing high amounts of IFN-alpha/-beta in PBMC elicited strong gamma delta T cell and NK cell responses, as determined by CD69 expression, IFN-gamma production, perforin content and lytic activity. These CpG ODN activated gamma delta T cells and NK cells in the absence of an additional stimulus and synergistically increased responsiveness to cell-type-specific antigens like isopentenylpyrophosphate for gamma delta T cells and NK-sensitive tumor cells for NK cells. NK cells and gamma delta T cells were activated via IFN-alpha/-beta released by CpG ODN-stimulated PBMC. Purified gamma delta T cells and NK cells did not respond to CpG ODN but to recombinant IFN-alpha/-beta. In conclusion, CpG ODN sequences were identified which, based on their ability to induce high amounts of IFN-alpha/-beta, represent strong adjuvants for "natural memory" cells including responses of gamma delta T cells to non-protein antigens. Early IFN-alpha/-beta dependent stimulation of IFN-gamma synthesis in NK cells and gamma delta T cells may contribute to the CpG ODN-induced Th1 bias of an evolving immune response.     

DNA activates human immune cells through a CpG sequence-dependent manner.

While bacterial DNA and cytosine-guanosine-dinucleotide-containing oligonucleotides (CpG ODN) are well described activators of murine immune cells, their effect on human cells is inconclusive. We investigated their properties on human peripheral blood mononuclear cells (PBMC) and subsets thereof, such as purified monocytes, T and B cells. Here we demonstrate that bacterial DNA and CpG ODN induce proliferation of B cells, while other subpopulations, such as monocytes and T cells, did not proliferate. PBMC mixed cell cultures, as well as purified monocytes, produced interleukin-6 (IL-6), IL-12 and tumour necrosis factor-alpha upon stimulation with bacterial DNA; however, only IL-6 and IL-12 secretion became induced upon CpG ODN stimulation. We conclude that monocytes, but not B or T cells, represent the prime source of cytokines. Monocytes up-regulated expression of antigen-presenting, major histocompatibility complex class I and class II molecules in response to CpG DNA. In addition, both monocytes and B cells up-regulate costimulatory CD86 and CD40 molecules. The activation by CpG ODN depended on sequence motifs containing the core dinucleotide CG since destruction of the motif strongly reduced immunostimulatory potential.     

Interleukin-12- and gamma interferon-dependent protection against malaria conferred by CpG oligodeoxynucleotide in mice

Unmethylated CpG dinucleotides in bacterial DNA or synthetic oligodeoxynucleotides (ODNs) cause B-cell proliferation and immunoglobulin secretion, monocyte cytokine secretion, and activation of natural killer (NK) cell lytic activity and gamma interferon (IFN-gamma) secretion in vivo and in vitro. The potent Th1-like immune activation by CpG ODNs suggests a possible utility for enhancing innate immunity against infectious pathogens. We therefore investigated whether the innate immune response could protect against malaria. Treatment of mice with CpG ODN 1826 (TCCATGACGTTCCTGACGTT, with the CpG dinucleotides underlined) or 1585 (ggGGTCAACGTTGAgggggG, with g representing diester linkages and phosphorothioate linkages being to the right of lowercase letters) in the absence of antigen 1 to 2 days prior to challenge with Plasmodium yoelii sporozoites conferred sterile protection against infection. A higher level of protection was consistently induced by CpG ODN 1826 compared with CpG ODN 1585. The protective effects of both CpG ODNs were dependent on interleukin-12, as well as IFN-gamma. Moreover, CD8+ T cells (but not CD4+ T cells), NK cells, and nitric oxide were implicated in the CpG ODN 1585-induced protection. These data establish that the protective mechanism induced by administration of CpG ODN 1585 in the absence of parasite antigen is similar in nature to the mechanism induced by immunization with radiation-attenuated P. yoelii sporozoites or with plasmid DNA encoding preerythrocytic-stage P. yoelii antigens. We were unable to confirm whether CD8+ T cells, NK cells, or nitric oxide were required for the CpG ODN 1826-induced protection, but this may reflect differences in the potency of the ODNs rather than a real difference in the mechanism of action of the two ODNs. This is the first report that stimulation of the innate immune system by CpG immunostimulatory motifs can confer sterile protection against malaria.     

丙型肝炎病毒CTL表位的HLA-A2限制性及其免疫学效应研究

目的 研究前期鉴定的5条丙型肝炎病毒(HCV)特异性细胞毒性T细胞(CTL)表位的HLA-A2限制性及其免疫学效应.方法 基于T2胞株,采用MHC-肽复合物稳定性试验研究前期鉴定的HCV特异性CTL表位与HLA-A2分子的亲和力;采用细胞内细胞因子染色(intracellular cy-tokine staining,ICS)和ELISPOT研究七述HLA-A2限制性CTL表位体外刺激HLA-A2刚性外周血单个核细胞(PBMC)产生肽特异性CTL的效应;采用CTL杀伤试验研究上述肽特异性CTL杀伤靶细胞(负载相同肽的T2细胞)的效应.结果 前期研究鉴定的5条CTL表位肽中,NS4b_78(SMMAF-SAAL)和NS5a_367(TVSSALAEL)与HLA-A2分子有高亲和力(FI1);ELISPOT结果显示NS4b_78(SMMAFSAAL)和NS5a_367(TVSSALAEL)可诱导高水平的分泌IFN-γ的效应细胞[分别为(60±6)SFC/10~4PBMC vs(4±1)SFC/10~4PBMC,P<0.001;(10±3)SFC/10~4PBMC vs(2±1)SFC/10~4PBMC,P<0.001];ICS结果证实这两条肽刺激HLA-A2阳性PBMC后,在CD8~+T细胞中产生了高百分比的CD8~+IFN-γ~+T[分别为(2.33±0.22)%vs(0.05±0.01)%,P<0.001;(0.36±0.06)%vs(0.03±0.01)%,P<0.001];并且,肽特异性CTL可特异性杀伤负载相同肽的T2细胞.结论 NS4b_78(SMMAFSAAL)和NS5a_367(TVSSALAEL)受HIA-A2限制,并具有较好的免疫原性.