献血员CD8~+T细胞的增加对CD4~+T细胞的抑制作用

实验发现 6 5 %体检合格的献血员外周血CD8+T细胞数量明显增加 ,并伴随CD16 +淋巴细胞数量的增加。这些异常的淋巴细胞与葡萄球菌肠毒素B (SEB )共同培养 6d ,CD4+T细胞无增殖反应。预先用抗CD8抗体去除CD8+T细胞 (去除率 >90 % )再用SEB刺激淋巴细胞 ,其应答能力恢复正常。增殖的细胞是CD4+T细胞 ,它们由 34 0 4%增加到 99 34%。CD8+T细胞由最初的 9 5 7%降低到 0 12 %。这些结果显示过量的CD8+T细胞有可能是被外原性抗原活化的T细胞。它们直接抑制CD4+T细胞对SEB的免疫应答反应 ,但不破坏CD4+T细胞的TCRVβ结构。     

CD4~+杀伤性T细胞在病毒感染和肿瘤性疾病中的研究进展

CD4+杀伤性T细胞是一群表达颗粒酶和穿孔素并通过其释放发挥直接杀伤作用的CD4+T细胞群。早期关于CD4+杀伤性T细胞的研究主要集中于体外培养环境中诱导出的杀伤性细胞。但是近年来逐渐发现其在很多病毒感染性疾病和肿瘤性疾病中发挥着重要作用。更好的理解其功能特点和作用机制,将为研发新的抗感染和抗肿瘤疫苗和新的免疫治疗策略提供思路。     

慢性乙型肝炎患者外周血CD8~+T细胞TCR Vβ基因亚家族克隆化的研究

目的:分析慢性乙型肝炎(CHB)患者CD8+T细胞TCR Vβ基因亚家族克隆化特征。方法:采用逆转录-聚合酶链反应(RT-PCR)扩增8例CHB患者外周血CD8+T细胞TCR Vβ基因22个亚家族的CDR3区,基因扫描技术对TCR Vβ亚家族的克隆化进行鉴定。结果:基因扫描显示所有8例CHB患者CD8+T细胞TCR Vβ基因亚家族均出现一个或一个以上单克隆或寡克隆增生。Vβ8、Vβ11、Vβ12出现单克隆增生的频率相对较高。8例健康者TCR Vβ基因亚家族均为多克隆。结论:CHB患者外周血CD8+T细胞TCR Vβ亚家族存在克隆性增生。     

人外周血CD4~+ IL-21~+记忆T细胞的特征

目的:探讨人外周血中白细胞介素21(IL-21)的产生细胞及其特征。方法:分离人外周血单个核细胞(PBMC),分为不刺激或anti-CD3(OKT3)、OKT3+anti-CD28、PMA+ionomycin刺激四个组,流式细胞术(FCM)检测产生IL-21的细胞亚群。PMA+ionomycin刺激PBMC、纯化CD4+、CD4+CD45RA-、CD4+CD45RA+细胞、脐带血单个核细胞(CB-MC),FCM分析产生IL-21细胞的表型特征和IL-21与Th1、Th2、Th17和Th22细胞因子之间的关系。结果:与OKT3、OKT3+anti-CD28相比,PMA+ionomycin能诱导最高量的IL-21产生。产生IL-21的主要细胞为CD4+T细胞,少数CD8+T细胞。CD4+IL-21+T细胞表达CD45RO,不表达CD45RA,其中部分细胞表达CCR6、CCR7或CXCR5。CD4+CD45RA-细胞表达IL-21远高于CD4+CD45RA+细胞。进一步研究表明,PBMC产生IL-21,而CBMC不产生。此外,大约24%的CD4+IL-21+细胞表达IFN-γ,小于10%CD4+IL-21+细胞表达IL-4、IL-17或IL-22。结论:人PBMC在多克隆刺激的条件下,可以诱导IL-21的产生。产生IL-21的主要细胞亚群具有记忆CD4+T细胞的表型。其中一部分CD4+IL-21+T细胞的表型独立于Th1、Th2、Th17和Th22细胞亚群。     

CD4~+CD25~+调节性T细胞和肿瘤免疫

近期研究发现一个有独特免疫调节功能的T细胞亚群 :CD4 + CD2 5 + 调节性T细胞 ,不仅能抑制自身免疫性疾病发生 ,还可能参与肿瘤免疫的调节。这群细胞具有免疫无能和免疫抑制特性 ,通过与细胞直接接触发挥作用 ,而不依赖于其分泌的细胞因子。肿瘤环境中CD4 + CD2 5 + 调节性T细胞比例增加 ,导致肿瘤免疫失调 ,去除这群细胞可有效诱导肿瘤免疫 ,为肿瘤治疗提供了一种新的方法。     

CD4~+CD25~+CD127~(low)识别人外周血CD4~+CD25~+调节性T细胞的优势

目的:探索可用于检测人外周血中CD4+CD25+Treg 细胞的最佳标记物.方法:以 52 名健康人和 47 名非血液系统肿瘤患者为研究对象,采用多色免疫荧光素标记和多参数流式细胞术同时检测外周血中CD4+CD25high、CD4+CD25+FoxP3+和 CD4+CD25+CD127lowT 细胞,并以经典指标CD4+CD25high 和 CD4+CD25+FoxP3+为标准,分析和比较CD4+CD25+CD127low作为识别CD4+CD25+ Treg 细胞的可行性及其优势.结果:健康人和肿瘤患者外周血 CD4+CD25high、CD4+ CD25+FoxP3+和CD4+CD25+CDl27+lowT 细胞占CD4+T 细胞百分比分别为(1.769±O.682)%和(2.958±1.392)%;(2.905±1.772)%和(5.128±2.227)%以及(5.396±1.306)%和(7.175±2.565)%.三者呈相同的趋势,即肿瘤患者组>健康人组,且三者之间呈显著正相关(P<0.05).用两种不同标记法高纯度分选CD4+ CD25high 和 CD4+CD25+CD127lowT 细胞群后,FoxP3 阳性率分别为90.9%和92.7%.结论:CD4+CD25+CD127low 三标记法可以帮助识别 CD4+CD25+Treg 和部分激活的 CD4+T 细胞,提高CD4+CD25+Treg细胞的可检出数量,并且不影响细胞活性度,是反映CD4+CD25+Treg 细胞更理想的指标.     

输注体外扩增的同源CD4~+CD25~+调节性T细胞增进小鼠肿瘤易感性

目的研究过继输注体外扩增同源调节性T细胞(Treg)对小鼠抗肿瘤免疫的影响,探索过继输注Treg治疗方法可能存在的风险。方法免疫磁珠分离法分离小鼠脾脏内CD4+CD25+Treg,流式细胞术测定其纯度后予以CD3/CD28单克隆抗体磁珠和大剂量IL-2(1 000 U/mL)刺激,进行2周2轮次扩增后收集Treg,混合淋巴细胞培养测定其体外抑制功能;后将1×107Treg静脉注射BALB/c小鼠,24 h后再注射B16F10肿瘤细胞,同时设置单独接种肿瘤细胞组,14 d后计数肺部移植瘤数目,测定外周血Treg比例。结果新鲜CD4+CD25+Treg纯度大于95%,平均96.3%±2.88%,体外扩增后纯度大于85%,平均87.73%±2.35%;与新鲜Treg相比,扩增后抑制功能未受损(P0.05);给BALB/c小鼠注射1×106B16F10细胞后14 d肺部肿瘤结节数为(14±5)个,先注射1×107体外扩增Treg后再注射1×106B16F10细胞,肿瘤结节数增多为(73±9)个(P=0.007),与单独注射2×106B16F10细胞相当(86±8)个(P=0.230);给C57BL/6小鼠输注5×105B16F10细胞后结节数为(70±15)个,预先输入8×106体外扩增Treg后再注射5×105B16F10细胞,肺部肿瘤结节数明显增多,大于300个,与前者相比,差异有统计学意义(P0.01),同时荷瘤小鼠外周血Foxp3+Treg比例上升更为显著(P0.05)。结论过继输注体外扩增Treg诱导移植物免疫耐受的同时,可能抑制机体的抗肿瘤免疫,因此存在一定风险。     

献血员CD8^＋T细胞的增另对CD4^＋T细胞的抑制作用

实验发现６５％体检合格的献血员外周血ＣＤ８＾＋Ｔ细胞数量明显增加,并伴随ＣＤ１６＾＋淋巴细胞数量的增加。这些异常的淋巴细胞与葡萄球菌肠毒素Ｂ（ＳＥＢ）共同２６ｄ,ＣＤ４＾＋Ｔ细胞无增殖反应。预先用抗ＣＤ８抗体去除ＣＤ８＾＋Ｔ细胞（去除率〉９０％）再用ＳＥＢ刺激淋巴细胞,其应答能力恢复正常,增殖的细胞是ＣＤ４＾＋Ｔ细胞,它们由３４．０４％增加到９９．３４％。ＣＤ８＾＋Ｔ细胞由最初的９．５７％降低到０     

CD4~+T细胞功能的双重性

<正> T细胞受体由 CD3分子与α、β两条异质性的肽链共同组成。已知T细胞分为OD4~+和CD8~+两个亚群。CD4~+细胞亚群并非都是T辅助细胞,因为①CD4~+细胞具有多种功能,只有一部分细胞能够活化抗原特异性B细胞;②CD4分子与识别连结在MHC分子的外来多肽抗原密切相关,它决定着MHCII     

无症状HBV携带者外周血CD4~+TCR Vβ基因亚家族克隆化特征的研究

分析无症状HBV携带者(AsC)CD4+TCR Vβ基因家族克隆化特征。采用逆转录-聚合酶链反应(RT-PCR)扩增7例AsC外周血CD4+TCR Vβ基因22个亚家族的CDR3区,基因扫描技术对CD4+TCR Vβ亚家族的克隆化进行鉴定。结果基因扫描显示,7例AsC CD4+TCR Vβ基因亚家族均出现一个或一个以上单克隆或寡克隆增生;7例健康者CD4+TCR Vβ基因亚家族均呈正态分布。提示,AsC外周血CD4+TCR Vβ亚家族存在克隆性增生,这可能与AsC免疫耐受的形成有关。     

The role of hepatitis C virus specific CD4+ T lymphocytes in acute and chronic hepatitis C

 Since the discovery of hepatitis C virus it has become clear that chronic hepatitis C is a major health problem throughout the world. Because antiviral agents are of limited value in the treatment of chronic hepatitis C, research has focused on the antiviral immune response for the development of both a protective vaccine and effective immunotherapies for established chronic infection. Antiviral antibodies are present in almost all patients with chronic hepatitis C but do not seem to be virus neutralizing, probably due to the high mutational rate of viral envelope proteins. Studies on the antiviral T cell response have revealed the presence of virus-specific CD4⁺ helper and CD8⁺ cytotoxic T cells in a substantial proportion of patients with chronic hepatitis C. Recent studies describe an association between strong CD4⁺ T helper cell activity to certain hepatitis C virus antigens and a self-limited course of acute hepatitis C and possibly also a sustained response to treatment with interferon-α. Therapeutic manipulation of the virus-specific T cell response may thus develop into a new approach for prevention and treatment of hepatitis C virus infection. Received: 12 March 1996 / Accepted: 18 June 1996     

T Cell Receptor (TCR) Repertoire in Alloimmune Responses

A large number of alloantigenic determinants could be generated by both the direct and indirect alloantigen presentation pathways. Hence, a heterogeneous population of T cells expressing a wide variety of receptors would be expected to respond to this diverse array of alloantigenic determinants. However, T cells expressing highly restricted T cell receptor (TCR) variable genes have been reported in a variety of alloimmune responses. A similar phenomenon has been observed in a wide variety of other immune responses, from those induced by superantigens, to very specific responses induced by a single peptide presented by a single MHC molecule. Given this scenario, the limited number of T cell clones which dominate an allograft rejection response, or for that matter an autoimmune response or a tumor specific response, could be therapeutically targeted by virtue of the selected TCR expression.     

乙型肝炎卡介苗联合疫苗与单价乙型肝炎疫苗免疫效果的比较

目的：比较乙型肝炎卡介苗联合疫苗与单价乙型肝炎疫苗的免疫效果。方法：实验动物采用豚鼠，按0、1、2月三针免疫程序接种，并于每针免疫后1个月采血，ELISA方法检测血清抗体滴度。实验分三部分进行。实验一：三种不同规格的联合疫苗与单价乙型肝炎疫苗的比较；实验二：同一规格连续三批联合疫苗与单价乙型肝炎疫苗的比较；实验三：联合疫苗与两种单价疫苗同时免疫的比较。结果：在三个实验中，联合疫苗组第一针血清抗体滴度均低于对照组，但无统计学差异：联合疫苗组第二、三针血清抗体滴度均高于对照组，也无统计学差异，实验组各组之间无明显差异。结论：联合疫苗组三针免疫程序的HBsAg的效力与单价乙型肝炎疫苗组相似。     

儿童接种新甲型(H1N1)流感疫苗后特异性CD4+ T细胞亚群的表型特征

目的 探讨儿童接种新甲型(H1N1)流感疫苗接种后远期疫苗特异性CD4+记忆T细胞亚群的特征.方法 根据自愿原则,选择31例接种甲型H1N1流感疫苗47个月后的儿童,取静脉血并分离淋巴细胞,细胞培养中滴入甲型H1N1流感疫苗,同时设不加疫苗刺激的作为对照组,流式细胞仪检测CD4+记忆T细胞亚群的表型特征.结果 外周血单个核细胞(PBMC)中CD4+疫苗特异刺激组为29.85％,对照组为39.00％,实验组低于对照组;CD4+初始T细胞实验组为74.32％,对照组为70.08％(P＞0.05);CD4+记忆T细胞实验组为28.54％,与对照组25.52％比较,无统计学意义(P＞0.05);记忆T细胞分中央型与效应型记忆T细胞,检测结果:CCR7和CD62L单阳性记忆T细胞亚群实验组分别为72.52％、29.85％,对照组分别为84.0％、93.44％,实验组的明显低于对照组(P＜0.05).结论 实验儿童初始T细胞比例都较高;甲型H1N1流感疫苗能诱导抗原特异性记忆CD4+T细胞的产生,可是为数较少,当中主要是中央型记忆CD4+T细胞,其中CCR7+和CD62L+记忆T细胞数量较低.     

湖北汉族人群对乙肝疫苗免疫应答的水平与HLA-I类分子多态性的相关研究

目的：探讨人群对乙肝疫苗免疫应答与ＨＬＡ遗传多态性的相关性。方法：对５２名湖北汉族健康自愿者进行ＨＢＶ血源疫苗标准全程接种,共３次（第０、１、６月）,末次接种后８ｗ用酶免疫法（ＥＩＡ）检测血清抗ＨＢｓ抗体水平：Ｓ／Ｎ≥２１为应答者;Ｓ／Ｎ＜２１为无应答者。同时对受试者进行ＨＬＡＩ类抗原多态性检测。结果：应答者４２人（８１０％）,无应答者１０人（１９０％）;无应答者与ＨＬＡＢ３９具有显著相关性,ＲＲ＝１７５,χ２＝５２２,Ｐ＜００５,而与ＨＬＡＢ６２呈负相关,χ２＝６４１,Ｐ＜００５。结论：在湖北汉族人群中,ＨＬＡＢ３９表型阳性个体对乙肝疫苗免疫应答水平明显低于其他个体,而ＨＬＡＢ６２表型阳性个体明显高于其他个体。     

Mini-review CD4 T cells are required for CD8 T cell memory generation

Whereas the role of CD4 T cells in B cell memory generation is well established and unequivocal, the role that CD4 T cells play in CD8 responses was until recently far more elusive and controversial. A series of recent reports, however, have re-assessed the role of CD4 help on CD8 responses and have given rise to surprisingly unambiguous conclusions. While studying very different systems, they demonstrated that CD4 T cells are absolutely required for the generation of bona fide CD8 memory cells; the reports allow, for the first time, strong analogies to be made between B and CD8 memory cell generation. These data invite us to drastically change our idea of CD4 help on CD8 responses because they show that the old dichotomy - Th-dependent versus Th-independent CD8 responses - is no longer accurate.     

Altered naive CD4 and CD8 T cell homeostasis in patients with relapsing-remitting multiple sclerosis: thymic versus peripheral (non-thymic) mechanisms

We have reported previously that naive T cells from relapsing-remitting multiple sclerosis (RRMS) patients have T cell receptor (TCR) repertoire shifts, but the basis of these TCR repertoire shifts was uncertain. Here, we questioned whether RRMS patients have altered naive CD4 and CD8 T cell homeostasis by studying homeostatic proliferation and thymic production in RRMS patients and healthy controls. We measured thymic production by quantifying signal joint T cell receptor excision circles (sjTRECs). Both naive T subsets from controls showed an age-associated decrease in sjTRECs, i.e. evidence of progressive thymic involution, but we detected no age-associated decrease in sjTRECs in RRMS patients. Instead, naive CD8 T cells from patients had lower sjTRECs (P = 0.012) and higher Ki-67 proliferation levels (P = 0.04) than controls. Naive CD4 T cell sjTRECs did not differ between patients and controls. However, in RRMS these sjTRECs correlated strongly with CD31, a marker expressed by newly generated CD4 T cells but not by naive CD4 T cells that have undergone homeostatic proliferation. HLA-DR2 positivity correlated negatively with naive CD4 T cell CD31 expression in RRMS (P = 0.002). We conclude in RRMS that naive T subsets have homeostatic abnormalities due probably to peripheral (non-thymic) mechanisms. These abnormalities could have relevance for MS pathogenesis, as naive T cell changes may precede MS onset.     

IL-12对结构优化的HBV核心抗原DNA疫苗诱导免疫应答的影响

目的 探讨IL-12对一种结构优化的HBV核心抗原(HBcAg)DNA疫苗免疫效果的影响。方法 将小鼠IL-12基因插入结构优化的DKA疫苗pST-HBc，构成pST-HBc/IL12，将pST-HBc／IL12转染COS7细胞，ELISA检测培养上清中的HBcAg和小鼠IL-12。分别将pST-HBc／IL12和pST-HBc肌肉注射接种BALB／c小鼠，检测小鼠的体液和细胞免疫应答。结果 ELISA检测到培养上清液中的HBcAg和小鼠IL-12，pST-HBc／IL12诱导的抗-HBc总IgG阳转率和抗体水平不及pST-HBc，但其诱导的脾细胞增殖反应和细胞毒性T淋巴细胞反应均强于pST-HBc。结论 IL-12可进一步增强这种HBcAgDNA疫苗诱导的细胞免疫应答。