流式细胞术鉴定人外周血滤泡辅助性T细胞

目的:用免疫荧光染色和流式细胞术(FCM)鉴定正常人外周血单个核细胞(PBMC)中滤泡辅助性T(Tfh)细胞, 以便对其功能进行进一步研究.方法:密度梯度离心法分离人PBMC, 采用不同荧光素标记的抗CXCR5、 CD4及CD19抗体进行染色FCM分析, 鉴定出表型为CD4+CXCR5+的T细胞亚群.结果:外周血可以检测到CD4+CXCR5+T细胞亚群, 占CD4+T淋巴细胞百分比为(11.09±0.38)%, MFI值为25.78±0.72, 低于B细胞膜表面CXCR表达水平(MFI值为99.6±8.1).结论:健康人外周血存在一定比例的Tfh细胞, 应用FCM可以成功鉴定Tfh细胞, 为进一步研究其功能提供了良好的技术平台.     

评估人T 淋巴细胞亚群对结核杆菌脂质抗原的免疫反应

目的:观察结核杆菌脂质的一些脂类抗原对人外周血中淋巴细胞活化和增殖的作用,进而探讨脂类抗原在结核感染中是否存在特异性的免疫作用。方法:取健康人外周血单个核细胞(PBMC),分离诱导出非成熟树突状细胞(im DC)后分别加入结核杆菌脂质全脂质(TLIP)、丙酮可溶性脂质(ASLIP)、纯硫脂(PSLIP)、脂阿拉伯糖(LAM)、脂甘露聚糖(LM)、同时设置非脂类抗原全菌裂解物(WCL)、培养分泌蛋白(CFP)、耐热抗原(Mtb-HAg)、脂多糖(LPS)和空白对照组。用CFSE标记自体淋巴细胞后,与被脂质抗原刺激后的DC共培养。之后,用流式细胞仪(FCM)检测T淋巴细胞亚群(CD4+、CD8+、NKT和γδT)的增殖和分泌细胞因子(IFN-γ、TNF-α和IL-4)的情况。结果:相较于空白组,所有脂质都能促进NKT细胞和CD8+T细胞增殖(P0.05)。相较于空白组ASLIP,LAM和LM可以促进非增殖的CD4+T细胞分泌IL-4,或者促进增殖的CD4+T细胞分泌IFN-γ(P0.05)。相较于空白对照组,所有脂质抗原(除了LM)都能促进增殖的γδT和CD8+T细胞分泌IFN-γ和TNF-α,而LM能抑制增殖的CD8+T细胞分泌TNF-α。结论:结核杆菌脂质抗原能激活PBMC的特异性免疫反应,特别是CD1限制性T细胞的应答。     

EIAV减毒疫苗诱导的特异性细胞免疫应答

目的：研究马传染性贫血病毒（EIAV）减毒疫苗株接种动物体内诱导的细胞免疫学反应方法：选用健康没有EIAV感染的马，接种EIAV减毒疫苗株DLV，运用流式细胞术检测疫苗株诱导的马外周血单核细胞（PBMC）中CD4和CD8阳性淋巴细胞数量的变化，以及^3H测定特异性淋巴细胞增殖反应和^51Cr释放实验测定淋巴细胞杀伤反应：结果：EIAV减毒疫苗株DLV免疫动物后，能够引起CD8^＋细胞明显增加．免疫马PBMC在EIAV刺激下．引起EIAV特异性淋巴细胞增殖反应（SI≥3），并能检测出EIAV特异性CTL活性，靶细胞杀伤百分率高于30％：结论：EIAV减毒疫苗株DLV免疫动物能够引起特异性EIAV细胞免疫反应，极有可能参与宿主的保护免疫作用。     

STUDY ON PERIPHERAL BLOOD MONONUCLEAR CELL(PBMC) PROLIFERATIVE RESPONSES TO DIFFERENT HCV ANTIGENS IN PATIENTS WITH HEPATITIS C

为探讨丙型肝炎(HC)病人细胞免疫功能和丙型肝炎病毒(HCV)的致病机制及机体对其免疫保护作用,收集24例HC病人(急性3例,慢性21例),用3H-TdR掺入法研究病人外周血单个核细胞(PBMC)对不同HCV抗原增殖反应,并用流式细胞仪(FACS)检测了PBMC中CD4+、CD8+淋巴细胞亚群在HCV抗原刺激后的变化.结果:HC病人PBMC对HCV合成肽CP9,NS和基因重组抗原C,E1,E2,NS3刺激后出现不同程度增殖反应,刺激指数(SI)分别为1.69±0.51,1.61±0.54,1.68±0.58,1.49士0.44,1.44±0.44和1.33±0.33.3例急性HC中2例病人的PBMC对HCV抗原呈有效增殖反应(SI≥2.1),且血清HCVRNA阴转伴ALT正常.细胞表型分析显示:增殖的细胞表型是CD4+淋巴细胞,而CD8+淋巴细胞增殖反应较弱.结论:HC病人PBMC确实存在对HCV抗原的增殖反应;CD4+淋巴细胞比CD8+淋巴细胞增殖反应要强,急性HC病人PBMC对HCV抗原有效的增殖反应预示可能有良好的临床愈合.     

连翘提取物对小鼠T淋巴细胞体外活化与增殖的影响

目的:分析连翘(FS)提取物对小鼠淋巴结T细胞的体外活化与增殖的影响,初步探讨其免疫抑制作用机制.方法:无菌分离小鼠淋巴结细胞,加入多克隆刺激剂刀豆蛋白A(ConA)进行刺激,利用荧光标记的单克隆抗体(mAb)染色结合流式细胞术(FCM),检测小鼠T淋巴细胞的表达的活化抗原CD69、CD25、CD71的表达情况;以羧基荧光素乙酰乙酸琥珀酰亚胺酯(CFDA-SE)染色,以FCM分析FS对淋巴细胞体外增殖的影响.结果:终浓度为40、80、160 mg/L的FS均对ConA刺激诱导的T细胞CD69、CD25和CD71的表达有降低作用(P＜0.05).CFDA-SE染色分析显示,上述浓度的FS对ConA诱导的小鼠T淋巴细胞增殖具有抑制作用(P＜0.05).结论:FS对ConA诱导的T细胞早、中、后期活化和体外增殖有抑制作用.     

四聚体技术检测人外周血巨细胞病毒抗原特异性CTL

为深入了解抗病毒免疫机制,探索人在健康状态及巨细胞病毒(CMV)急性感染时抗原特异性细胞毒T淋巴细胞(CTL)数量的动态变化。以CMV抗原肽、HLA-A*0201重链和轻链制备CMV四聚体;分离并检测12名健康被检者外周血单个核细胞(PBMC)中CMV抗原特异CTL数量;PBMC体外培养建立CTL细胞系,于末次刺激的不同时相进行四聚体染色,流式细胞仪(FACS)检测抗原特异CTL数量。结果发现9名被检者PBMC中均检出抗原特异CTL;细胞系中CMV特异性CTL数量急剧增多,细胞系与PBMC相比,差异有显著的统计学意义(P<0.001);研究结果提示,9名被检者感染过CMV,血液中存在少量免疫记忆性T细胞,当再次遭遇同一抗原后发生克隆扩增。     

婴儿肠道不同部位T细胞亚群及其表面分子检测——婴儿肠道HIV-感染和复制的可能性分析

通过对婴儿外周血(PB)、肠系膜淋巴结(MLN)和肠上皮内(IE)来源淋巴细胞的比较性研究,以分析婴儿肠道HIV-1感染容许性和HIV-1复制支持性的细胞与分子基础。分离婴儿外周血单个核细胞(PBMC),肠系膜淋巴结淋巴细胞(MLNL)和肠上皮间淋巴细胞(iIEL),制备单细胞悬液,运用流式细胞术结合荧光抗体染色技术:(1)检测不同部位的CD3+T细胞中CD4+辅助性T细胞和CD8+杀伤性T细胞比例;(2)检测不同部位的CD4+T细胞CCR5和CXCR4以及CD69和HLA-DR的表达水平。结果发现:(1)iIEL中的CD4+辅助性T细胞占CD3+T细胞的比例明显低于PBMC和MLNL,而CD8+杀伤性T细胞占CD3+T细胞的比例明显高于PBMC和MLNL;(2)iIEL中CD4+T细胞CCR5和CXCR4以及CD69和HLA-DR的表达水平均明显高于PBMC和MLNL。结果表明:婴儿iIEL中CD4+T淋巴细胞与PBMC和MLNL的CD4+T淋巴细胞相比较,高表达HIV-1入胞共受体CCR5和CXCR4,提示iIEL更易被HIV-1感染;iIEL中CD4+T淋巴细胞高表达细胞活化标记分子CD69和HLA-DR,说明其更有利于HIV-1复制,这种高基础活化率可能与其不断接触小肠来源的食物和共生菌抗原有关。由此可见,婴儿肠道具有了HIV-1感染容许性和HIV-1复制支持性的细胞和分子基础,因此成了HIV-1最易感的解剖部位,这可能是围产期HIV感染的婴儿病毒载量明显高于成年人,且病情进展也比成年人快的原因。     

儿童新甲型流感疫苗远期特异性CD8+记忆T 细胞的表型特征

目的:探讨儿童新甲型(H1N1)流感疫苗接种后远期外周血疫苗特异性CD8~+记忆T细胞的特征。方法:选择31例于2009年12月~2010年1月接种甲型H1N1流感疫苗的3~6岁儿童,抽取外周静脉血5 ml,分离淋巴细胞加入甲型H1N1流感疫苗进行培养,并设对照组,用流式细胞仪检测细胞表面分子的表达,同时以CCK-8法检测细胞增殖,计算细胞增殖指数。结果:外周血PBMC中CD8~+T细胞在实验组和对照组分别是13.41%与9.41%,P0.05。CD8~+初始T细胞在两组的比例均高达80%上;CD8~+记忆T细胞在两组占17%~19%;记忆T细胞分中央型和效应型记忆T细胞,两个亚群检测结果:CCR7和CD62L单阳性记忆T细胞亚群在实验组占比明显低于对照组的占比,P0.05。应用CCK-8法检测疫苗刺激后抗原特异性增殖,检测结果见细胞增殖指数大于0.8的仅为51.16%,大于1.0在本研究中没有。结论:31例儿童外周血PBMC中CD8~+T细胞占比少,初始T细胞CD45R+均较高,具有抗原再刺激后再应答的基础;甲型H1N1流感疫苗可以诱导抗原特异性记忆CD8~+T细胞的产生,但数量不多,其中大多数为中央型记忆CD8~+T细胞;细胞增殖指数结果表明疫苗特异性细胞增殖不佳;提示对该疫苗的远期疫苗特异性CD8~+T细胞免疫记忆不理想。     

四聚体技术检测人外周血巨细胞病毒抗原特异性OTL

为深入了解抗病毒免疫机制,探索人在健康状态及巨细胞病毒（CMV）急性感染时抗原特异性细胞毒T淋巴细胞（CTL）数量的动态变化.以CMV抗原肽、HLA-A＊0201重链和轻链制备CMV四聚体;分离并检测12名健康被检者外周血单个核细胞（PBMC）中CMV抗原特异CTL数量;PBMC体外培养建立CTL细胞系,于末次刺激的不同时相进行四聚体染色,流式细胞仪（FACS）检测抗原特异CTL数量.结果发现9名被检者PBMC中均检出抗原特异CTL;细胞系中CMV特异性CTL数量急剧增多,细胞系与PBMC相比,差异有显著的统计学意义（P＜0.001）;研究结果提示,9名被检者感染过CMV,血液中存在少量免疫记忆性T细胞,当再次遭遇同一抗原后发生克隆扩增.     

多肽类结核杆菌抗原激活的γδ T细胞表达抗原提呈细胞表型和功能

目的:观察用多肽类结核杆菌耐热抗原(Mtb-HAg)激活的人外周血γδ T细胞是否具有抗原提呈细胞的表型和抗原提呈作用.方法:外周血单个核细胞(PBMC)经贴壁法获取单核细胞, 加GM-CSF, IL-4和LPS培养诱导为成熟DC.PBMC用Mtb-HAg优势扩增γδT细胞后用流式分选纯化γδ T(Vδ2+)细胞.PBMC经尼龙毛柱法获得纯化T细胞, 用CFSE标记后单独加Mtb分泌性抗原(Mtb-SAg), 或加单核细胞和Mtb-SAg共同培养, 或与经Mtb-SAg预处理的成熟DC或活化γδT细胞共同培养.第11天时用流式细胞术检测CD4+T细胞的增殖.Mtb-HAg活化的γδ T细胞与FITC标记的Mtb-SAg孵育不同时间后用流式细胞术和激光共聚焦显微镜检测摄入情况.结果:Mtb-HAg活化的γδ T细胞CD80, CD86和MHC-Ⅱ类分子的表达显著增加.Mtb-SAg预处理活化的γδ T细胞诱导初始T 细胞增殖数和CD4+T细胞增殖指数的活性与成熟DC相似.Mtb-HAg活化的γδ T细胞能摄入FITC标记的Mtb-SAg.结论:用多肽类 Mtb-HAg激活的γδ T细胞具有抗原提呈细胞的表型, 并具有摄入和提呈可溶性抗原给初始T淋巴细胞的能力.     

Identification of broadly recognized, T helper 1 lymphocyte epitopes in an equine lentivirus

Equine infectious anaemia virus (EIAV) is a horse lentivirus causing lifelong, persistent infection. During acute infection, CD8(+) cytotoxic T lymphocytes (CTL) are probably involved in terminating plasma viraemia. However, only a few EIAV CTL epitopes, restricted to fewer horse major histocompatibility complex (MHC) class I alleles, are known. As interferon-gamma (IFN-gamma)-secreting CD4(+), T helper 1 (Th1) lymphocytes promote CTL activity and help maintain memory CTL, identifying broadly recognized EIAV Th1 epitopes would contribute significantly to vaccine strategies seeking to promote strong CTL responses among horses with varying class I haplotypes. To this end, peripheral blood mononuclear cells (PBMC) from 10 MHC disparate, EIAV-infected horses were tested in T-lymphocyte proliferation assays for recognition of peptides from the Gag p26 capsid region and a portion of Pol. Both regions are highly conserved among EIAV isolates, and this Pol region is 51-63% homologous to other lentiviral Pol proteins. Seven of 10 horses recognized peptide Gag 221-245, and peptides Gag 242-261 and Pol 323-344 were recognized by five and four horses, respectively. Furthermore, the Gag peptides were recognized by two additional horses after resolving their initial plasma viraemia, indicating that these two peptides can be immunodominant early in infection. Gag peptide-responsive PBMC produced only IFN-gamma, indicating a Th1 response, while Pol 323-344-responsive PBMC produced IFN-gamma both with and without interleukin-4. PBMC from uninfected horses failed to either proliferate or secrete cytokines in response to peptide stimulation. Finally, CD4(+) T lymphocytes were required for proliferation responses, as shown by assays using CD4- versus CD8-depleted PBMC.     

活体染料CFDA-SE在淋巴细胞增殖研究中的应用

目的 :探讨活体染料CFDA SE在淋巴细胞增殖研究中的应用价值。方法 :利用CFDA SE染色、荧光抗体标记和流式细胞术 ,检测淋巴细胞及其亚群在多克隆刺激剂作用下荧光强度的变化 ,并应用相关软件分析其增殖情况。结果 :PDB ion omycin或ConA刺激 4 8h后均出现淋巴细胞分裂 ,表现为CFSE荧光强度的系列减半。环孢菌素A(CsA)可抑制ConA促进淋巴细胞增殖的作用 ,CFSE荧光无减半。ConA刺激4 8h后 ,出现CD4 T细胞和CD8 T细胞增殖不同步的现象 ,72h后这一现象更加明显。经ModFitTM 软件拟合后 ,得到的各项增殖指标显示 ,ConA对CD8 T细胞的促增殖作用强于对CD4 T细胞的作用。结论 :CFDA SE染色结合荧光抗体标记和流式细胞术 ,是分析淋巴细胞增殖的有力工具     

CD8+ T细胞对HIV-1合成表位的免疫主导应答研究

目的研究CD8^＋ T细胞对人免疫缺陷病毒1型（HIV-1）表位的免疫主导应答。方法分别采用酶联免疫斑点技术（ELtSPOT）和羧乙基锗倍半氧化物（CFSE）标记流式分析技术，以覆盖HIV-1 Env、Pol、Gag、Vif、Nef、Tat区的701个重叠肽段组成的34个肽段库及其部分单肽段作为刺激表位，对一例感染HIV-1的长期不进展者（LTNP）的外周血单个核细胞（PBMC）中CD8^＋ T细胞的了γ-干扰素（IFN-γ）分泌细胞频率和细胞增殖率进行了测定研究。结果HIV-1 Gag区域肽段诱导产生的CD8^＋ T细胞的IFN-γ分泌细胞频率最高，Nef、Tat、Vif区域依次顺减，Env和Pol区域不能诱导产生显著性应答；在IFN-γ ELISPOT实验中，肽段和相应肽段库刺激产生的结果一致；CD8^＋ T细胞在单肽段刺激下，用ELISPOT技术测定的IFN-γ分泌细胞频率和CFSE标记流式分析技术测定的细胞增殖率显示出较好的相关性。结论CD8^＋ T细胞能特异性识别某些HIV-1抗原表位，诱导出免疫主导应答；当进行HIV-1特异性CD8^＋ T细胞反应增殖测定和免疫主导应答研究时，ELISPOT是值得称道的标准实验，同时，推荐一种新颖的CFSE标记流式分析技术。     

Advanced age in horses affects divisional history of T cells and inflammatory cytokine production

A number of model systems have been employed to investigate age-associated changes in immune function. The purpose of the current study was to characterize senescent T cells and to investigate the inflamm-aging phenomenon both in vitro and in vivo using the old horse as a model. We examined whether decreased T cell proliferation induced by Con A is caused by increased apoptosis. We also utilized intracellular CFSE to analyze changes within each round of cell proliferation, in particular cytokine production. Intracellular staining with flow cytometry, RT-PCR, and ELISA were used to measure pro-inflammatory cytokines both in vitro and in vivo. While lymphocytes from old horses exhibit decreased proliferation, this is not the result of increased apoptosis. Instead, a larger percentage of the T cells remain in the parent generation and produce significant amounts of IFNgamma. Likewise, old horses have increased frequency of CD8-IFNgamma+ T cells and TNFalpha producing cells. We also show that old horses have elevated levels of IL-1beta, IL-15, IL-18 and TNFalpha gene expression in peripheral blood and significant levels of TNFalpha protein in serum, all characteristics of inflamm-aging.     

间充质干细胞对混合淋巴细胞反应体系中T淋巴细胞的免疫调节作用

目的:探讨间充质干细胞(MSC)在体外对T淋巴细胞免疫调节作用的特点。方法:通过Ficoll梯度密度离心法分离出正常人骨髓单个核细胞,体外培养扩增MSC,获取第3代细胞。将其按照不同的比例加入双向混合淋巴细胞培养(MLC)体系中,在第3、5天,采用MTT比色法检测各组MLC中的T淋巴细胞的增殖情况,再用流式细胞术分析其与MSC共孵育前后细胞表面标记的变化情况。结果:加入了MSC的MLC体系中,MSC对T淋巴细胞的增殖抑制具有剂量依赖性,且随着时间延长,抑制程度增强;其中,CD4 T细胞亚群受抑不如CD8 T细胞亚群显著;另外,T淋巴细胞表面CD25的表达虽然较对照组有所下降,但是CD4、CD25共表达的细胞却较对照组有明显的上升趋势。T淋巴细胞表面活化抗原HLA-DR的表达较对照组有轻度减低。结论:MSC在体外能够明显抑制T淋巴细胞的增殖,其主要是针对CD8 T细胞(CTL)。另外,它还能下调活化T淋巴细胞上一些较特异的表面标记CD25和HLA-DR的表达。     

High dose allergen stimulation of T cells from house dust mite-allergic subjects induces expansion of IFN-gamma+ T Cells, apoptosis of CD4+IL-4+ T cells and T cell anergy

BACKGROUND: During clinically effective allergen-specific immunotherapy a shift in cytokine dominance from IL-4, IL-5 predominant to IFN-gamma predominant has been observed. As antigen concentration influences Th cell priming, this study aimed to determine the effect of different allergen concentrations on human house dust mite (HDM)-specific T cell production of IL-4 and IFN-gamma, proliferation and apoptosis. METHODS: HDM-allergic donor PBMC were cultured for 14 days with different concentrations of HDM extract (1, 10 and 100 microg/ml). T cell intracellular IL-4 and IFN-gamma, division (CFSE labelling) and apoptosis (active caspase-3 staining) were analysed by flow cytometry. Proliferation was assessed by (3)H-thymidine incorporation. RESULTS: Increased CD4+IFN-gamma+ and CD8+IFN-gamma+ T cell numbers were observed in high allergen concentration cultures compared with low concentration cultures whereas there were no differences in CD4+IL-4+ and CD8+IL-4+ T cell numbers. CFSE cell labelling revealed that high allergen concentration favours the expansion of IFN-gamma-producing CD4+ T cells. The proportion of apoptotic cells increased with allergen concentration and there was preferential apoptosis of CD4+IL-4+ T cells. HDM-induced proliferation was decreased in high allergen concentration cultures; this was reversible by IL-2 consistent with anergy. CONCLUSION: These results show that T cell division and apoptosis contribute to the cytokine skewing to predominant IFN-gamma production by T cells observed at high allergen concentration. Thus the use of hypoallergenic T cell reactive preparations which can be given safely at higher doses than natural extracts may enhance efficacy of allergen-specific immunotherapy.     

耐受性CD8~+ NKT细胞体外增殖能力的鉴定

目的:利用CFSE标记细胞,流式细胞术(FCM)检测法,解析超抗原SEB活化的耐受性CD8+ NKT细胞在体外增殖的情况。方法:利用CFSE标记新鲜分离的C57BL/J鼠脾细胞,分别与ConA和LPS共同培养3d,收集细胞进行荧光染色并用FCM解析细胞表面CD69分子的表达率和增殖能力。CFSE标记的鼠脾细胞与SEB共培养5d和10d后,荧光染色并用FCM解析细胞表面CD69的百分数和增殖能力。SEB活化的第10天细胞经CFSE标记后在IL-2的协同作用下继续培养10d,荧光染色,FCM解析这群细胞的增殖能力、活性分子CD69的表达率和NKT细胞亚群的变化情况。结果:ConA、LPS和SEB三者均可以刺激小鼠脾细胞增殖。ConA和LPS在3d内可以使细胞增殖3代,且CD69的表达率为74.19%和41.56%;SEB在5d和10d内分别可以使细胞增殖5代和7代,细胞表面CD69的表达率为32.09%和48.66%。SEB活化的10d细胞可以在IL-2的协同下继续传代培养10d,可以增殖7代;这群细胞中CD8+ NKT细胞亚群,由原始的0.36%增加到38.58%;细胞表面CD69分子由正常值的0.11%提高到83.74%。结论:超抗原SEB活化的CD8+ NKT细胞可以在体外进行增殖培养,且这些细胞是活性化的细胞。利用CFSE标记细胞,FCM可以检测耐受性CD8+ NKT细胞在体外的增殖水平。     

氧化苦参碱对淋巴细胞增殖和调节性T细胞（Tr）数量的影响

目的： 分析氧化苦参碱（OMT）对小鼠外周血调节性T细胞（Tr细胞）数量及其对刀豆蛋白A(Con A) 刺激的小鼠淋巴结T细胞增殖的影响, 探讨OMT治疗ACD的免疫学机制。方法： 建立DNFB诱发的小鼠ACD模型，腹腔注射（ip）不同剂量的OMT、PBS、氢化可的松(HCT)，在实验的第1 d、7 d、14 d、21 d、28 d小鼠尾静脉采血, 应用抗-CD3、抗-CD4、抗-CD25单抗进行免疫荧光标记, 流式细胞术检测各组CD4+CD25+T细胞数量。利用羧基荧光素乙酰乙酸(CFDA-SE)染色，流式细胞术检测OMT对小鼠淋巴结T细胞增殖的影响。结果： 500、125和31 mg/L OMT对小鼠淋巴结T细胞增殖呈剂量依赖性抑制，而16、8、4、2 mg/L OMT可促进小鼠淋巴结T细胞增殖，但剂量依赖关系不明显。腹腔注射OMT能明显提高小鼠外周血中CD4+CD25+T细胞数量, 与HCT组、PBS组比较（P<0.01）。结论: OMT对小鼠淋巴结T细胞增殖呈双向作用；腹腔注射OMT能明显提高小鼠外周血中CD4+CD25+T细胞数量；提示:OMT是一种双向免疫调节剂。     

Interleukin-2 reconstitutes defective human immunodeficiency virus (HIV), and cytomegalovirus (CMV) specific CD8+ T cell proliferation in HIV infection

Recent studies indicate that a defective proliferative response of HIV-specific CD8+ T cells is associated with the lack of virologic control in chronic HIV infection in humans. The possible mechanisms that might be responsible for the reduced proliferative potential of HIV-specific CD8+ T cells and conditions conducive to the proliferation of CD8+ T cells were examined in 14 HIV-infected individuals and 7 HIV-uninfected controls using CFSE labeling and flow cytometry techniques, and analyzed data using 2 quantitative measurements: the percentages of proliferating CD8+ T cells (Tp), and the maximum number of cell divisions (Dm) after stimulation. It was found that CD8+ T cells from HIV-infected and -uninfected subjects proliferated equally well after polyclonal stimulation by phylohemagglutinin A (PHA); both groups reached a Tp of 92%-96% and a Dm of 5-8. However, in HIV-infected subjects, proliferation of HIV- and CMV-specific CD8+ T cells was significantly reduced compared to proliferation of CMV- specific CD8+ T cells from HIV-uninfected subjects. These defective proliferative responses of HIV- and CMV-specific CD8+ T cells were restored by the addition of IL-2 at the time of stimulation. These results may have implications for the design of immune modulation strategies in vivo.     

A sensitive method for detecting proliferation of rare autoantigen-specific human T cells

The ability to measure proliferation of rare antigen-specific T cells among many bystanders is critical for the evaluation of cellular immune function in health and disease. T-cell proliferation in response to antigen has been measured almost exclusively by 3H-thymidine incorporation. This method does not directly identify the phenotype of the proliferating cells and is frequently not sufficiently sensitive to detect rare autoantigen-specific T cells. To overcome these problems, we developed a novel assay for antigen-specific human T-cell proliferation. Peripheral blood mononuclear cells (PBMC) were labelled with the fluorescent dye 5,6-carboxylfluorescein diacetate succinimidyl ester (CFSE) and cells that proliferated in response to antigen, with resultant reduction in CFSE intensity, were measured directly by flow cytometry. This assay was more sensitive than 3H-thymidine incorporation and detected the proliferation of rare antigen-specific CD4(+) T cells at 10-fold lower antigen concentrations. It also allowed the phenotype of the proliferating cells to be directly determined. Using the CFSE assay we were able to measure directly the proliferation of human CD4(+) T cells from healthy donors in response to the type 1 diabetes autoantigens glutamic acid decarboxylase (GAD) and proinsulin (PI).