HIV-1B/C重组病毒感染者Gag特异性T淋巴细胞免疫应答的研究

目的 研究中国主要流行的HIV-1 B/C重组毒株感染者Gag特异性T淋巴细胞反应特征.方法 本研究以10例感染时间＜1年和25例感染时间＞3年未接受抗病毒治疗的HIV-1 B/C重组毒株感染者为研究对象,以10例HIV-1阴性健康人作为对照,用Elispot方法检测其针对HIV-1B/C同义B Gag重叠多肽产生γ干扰素的特异性T淋巴细胞反应.结果 8例(8/10)感染时间＜1年的HIV-1 B/C重组毒株感染者产生Gag特异性分泌γ干扰素的T淋巴细胞反应,主要识别散在分布的五条多肽;17例(68％)感染时间＞3年的感染者产生反应,主要识别p17区域内的一条和p24区域内六条多肽.感染时间＞3年组产生IFN-γ的特异性T淋巴细胞反应强度与病毒载量呈明显正相关(P =0.0318,r=0.519),感染时间＜1年的感染者反应强度明显高于感染时间＞3年的感染者(P=0.021).健康人对照组无阳性反应.结论 HIV-1 B/C重组病毒感染者在疾病进程不同阶段识别Gag的不同区域.     

HIV-1B／C重组病毒感染者Gag特异性T淋巴细胞免疫应答的研究

目的研究中国主要流行的HIV-1B／C重组毒株感染者Gag特异性T淋巴细胞反应特征。方法本研究以10例感染时间〈1年和25例感染时间〉3年未接受抗病毒治疗的HIV-1B／C重组毒株感染者为研究对象,以10例HIV．1阴性健康人作为对照,用Elispot方法检测其针对HIV-1B／C同义BGag重叠多肽产生1干扰素的特异性T淋巴细胞反应。结果8例（8／10）感染时间〈1年的HIV-1B／C重组毒株感染者产生Gag特异性分泌Y干扰素的T淋巴细胞反应,主要识别散在分布的五条多肽;17例（68％）感染时间〉3年的感染者产生反应,主要识别p17区域内的-条和p24区域内六条多肽。感染时间〉3年组产生IFN-吖的特异性T淋巴细胞反应强度与病毒载量呈明显正相关（P=0．0318,r=0．519）,感染时间〈1年的感染者反应强度明显高于感染时间〉3年的感染者（P=0．021）。健康人对照组无阳性反应。结论HIV-1B／C重组病毒感染者在疾病进程不同阶段识别Gag的不同区域。     

中国HIV-1 C/B'重组毒株和B'毒株感染者Nef特异性T细胞免疫应答的研究

目的 研究中国主要流行的HIV-1 C/B'重组毒株和B'亚型毒株感染者Nef特异性T细胞反应特征,确定两种亚型感染者共同识别的免疫优势区.方法 本研究以59名HIV-1 C/B'重组毒株、27名B'亚型毒株感染者为研究对象,用ELISPOT检测针对HIV-1型C/B'Nef重叠多肽产生IFN-γ的特异性T细胞反应.结果 44例(74.58%)HIV-1 C/B'重组毒株感染者产生Nef特异性T细胞反应,主要识别EVA7081.1、5、6、7、43、44、45、47、48、49这10条多肽,氨基酸序列为Nef63～115和117～139的区域.20例(74.07%)的HIV-1 B'毒株感染者产生Nef特异性T细胞反应,主要识别EVA7081.1、2、43、49这4条多肽,氨基酸序列为Nef 63～77和87～119的区域.两种亚型感染者特异性T细胞反应的强度和广度与病毒载量和CIM细胞数不相关.结论 中国HIV-1 C/B'重组毒株和B'亚型毒株感染者共同识别氨基酸序列为Nef63～77和87～115的免疫优势区,提示此区域可用于疫苗的设计.     

HIV-1蛋白诱导T细胞产生IFN-γ反应特征及对HIV-1感染者病情进展的影响

目的 探讨HIV-1特异性T细胞反应特征及对HIV-1感染者病情进展的影响.方法 通过合成重叠肽技术及ELISPOT技术,采用队列研究方法对37名HIV-1感染者的病毒特异性T细胞免疫反应进行分析.结果 83.78%(31/37)的HIV-1感染者对1个或多个合成肽反应(反应强度大于50 SFU/106 PBMCs).HIV-1B型病毒不同蛋白均可激发HIV-1感染者的特异性T细胞反应,其中HIV-1 Gag蛋白被识别的频率最高,81%的HIV-1感染者识别HIV-1 Gag而且HIV-1 Gag蛋白诱导的T细胞反应强度最高,相对强度达到28.25%,明显高于其他蛋白,差异具有统计学意义(F=17.969,P<0.001);重叠肽诱导T细胞分泌IFN-γ反应频率、反应强度在HIV-1感染无症状期和艾滋病期无明显区别,但是HIV-1 Gag蛋白诱导的T细胞反应强度在无症状期明显高于艾滋病期.结论 HIV-1B型病毒不同基因编码蛋白激发T细胞分泌IFN-γ反应小同,其中HIV-1 Gag蛋白特异性T细胞在控制病情进展方面发挥了重要作用.     

SARS康复者M抗原特异性记忆性T细胞免疫应答的探讨

目的探讨SARS患者康复后,外周血单个核细胞（PBMCs）中是否存在SARS-CoV M抗原特异性T细胞。方法从完全康复期SAILS患者和健康人外周血中分离PBMCs,体外经M混合多肽刺激后,采用酶联免疫吸附试验（ELISA）、酶联免疫斑点试验（ELISpot）及流式细胞仪检测技术,分析抗原特异性T淋巴细胞的反应性。结果在未经任何抗原刺激的情况下,PBMCs几乎不分泌IFN-γ。当SARS-CoV M混合多肽刺激后,SARS康复期患者的PBMCs分泌大量的IFN-γ,并可检测出高频率的IFN-γ产生细胞。与健康刺激组及康复期SAILS患者未刺激组相比,差异显著（P〈0．05）。流式结果显示,SAILS康复期患者PBMCs经M多肽刺激后,分别有0．11％CD4^＋和0．16％CD8^＋T淋巴细胞分泌IFN-γ。根据IFN-γ和IL-2的表达与否,可将CD4^＋T细胞分为三个亚群：IFN-γ^-IL-2^＋、IFN-γ^＋IL-2^＋和IFN-γ^＋IL-2^-。结论SARS-CoV感染后,机体可以产生针对SARS-CoV M蛋白的抗原特异性细胞免疫反应,其免疫记忆可以在体内维持很长时间。     

HBV特异性IFN-γ分泌细胞的体外扩增和功能研究

目的:体外分离扩增HBV多肽特异性IFN-γ分泌细胞,并进行自体扩增,检测其扩增后的多肽特异和IFN-分泌功能。方法:酶联免疫斑点法筛选HBV自然感染献血个体,分离外周血单核细胞,体外刺激并分选IFN-γ分泌细胞,并进行自体细胞体外扩增,流式细胞术检测扩增后细胞的CD4、CD8表型,多肽负载自体淋巴瘤细胞系(lymphoblastoid cell lines,LCLs)细胞检测其多肽特异性和IFN-γ分泌能力。结果:经过4周体外自体扩增,HBV特异性IFN-γ分泌细胞扩增数量达1000多倍,CD4和CD8比例变化不显著,4周扩增后的T淋巴细胞能有效识别HBV特异性多肽并分泌IFN-γ。结论:HBV多肽特异性IFN-γ分泌细胞能在体外有效扩增并保持功能表型不变。     

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。     

CD4+CD25 nt/hi CD127lo调节性T细胞对HIV感染者免疫状态及病程进展的影响

目的:探讨具有CD4 CD25nt/hi CD127lo特征的调节性T细胞频率对中国HIV-1感染者免疫状态及病程进展的影响.方法:选取100名未经治疗的HIV-1感染者和4个年龄组的312名健康人对照,采集静脉血,经三重免疫荧光染色,用流式细胞术分析CD4 CD25 Treg表型和CD4 CD25nt/hiCD127loTreg频率并进行CD4 T细胞绝对计数;应用酶联免疫斑点技术(ELISpot)在单细胞水平观察受试者的HIV-1特异性细胞免疫功能;平行检测HIV感染者的病毒载量(NASBA方法).结果:不同病程的HIV-1感染者外周血中CD4 CD25nt/hiCD127loTreg频率存在差异,进展期高于新近感染者(P＜0.001),其平均水平显著高于健康人(P＜0.001);CD4 CD25nt/hiCD127loTreg频率与HIV感染者CD4 T细胞数量呈显著负相关(r=0.354,P＜0.01),与病毒载量呈明显正相关(r=0.287,P＜0.01);高频率CD4 CD25nt/hiCD127loTreg HIV-1感染者(进展期)的外周血PBMCs经HIV-1多肽刺激后分泌IFN-γ的CD8 T细胞频率明显低于无症状的新近感染者.结论:初步证实HIV-1感染者外周血中CD4 CD25nt/hiCD127kloTreg细胞频率增加与CD4 T细胞数量降低及病程进展相关;高频率CD4 CD25nt/hiCD127lo Treg细胞对HIV-1感染者的细胞免疫功能具有抑制作用.本结果为进一步阐明HIV持续感染的免疫机制提供了新依据.     

含HIV-1核心蛋白基因的重组质粒的构建及其免疫应答的研究

目的构建含有HIV-1核心蛋白gag基因的真核表达质粒,并研究其免疫应答反应。方法采用PCR方法从1例HIV感染者中扩增出gag基因,构建重组质粒pcDNA-GAG。接种小鼠后,检测其抗体及抗体亚类,并对小鼠的淋巴细胞亚群进行分析,采用3H-TdR法、ELISPOT方法和51Cr释放法分别检测T淋巴细胞的增殖反应性、特异性分泌IFN-γ的CD8+T淋巴细胞以及特异性CTL杀伤活性。结果重组质粒体外表达目的蛋白的相对分子质量(Mr)约为55×103。免疫小鼠后可诱导产生特异性抗体,其中IgG2a与IgG的比例显著高于IgG1与IgG的比例;T淋巴细胞体外经ConA刺激后SI达到160.67,显著高于对照组(14.04,P<0.05);产生IFN-γ的CD8+T淋巴细胞数目以及特异杀伤率均显著高于对照组小鼠(P<0.05)。结论重组质粒pcDNA-GAG可诱导小鼠产生特异性体液和细胞免疫应答反应,而且ELISPOT方法检测特异性细胞免疫应答反应的结果与51Cr释放法一致,提示可用此法对DNA疫苗诱导的细胞免疫进行评价。     

HIV-1感染者T细胞分泌TGF-β和IL-10水平及其抑制作用的研究

目的探究我国HIV-1感染者T细胞分泌TGF-β和IL-10的水平,以及重组IL-10(r IL-10)和重组TGF-β(r TGF-β)对T细胞功能的影响。方法分离HIV-1感染者PBMC,加入r IL-2、r IL-15、r IL-12细胞因子体外刺激,采用胞内染色、流式细胞术检测T细胞内TGF-β、IL-10的产生情况。结果 HIV-1感染者总T细胞和CD8~+T细胞分泌的TGF-β明显高于正常人(P=0.000 1,P=0.003),分泌的IL-10在HIV-1感染者和正常人之间没有统计学差异;总T细胞分泌的TGF-β、IL-10与CD8~+T细胞分泌的TGF-β、IL-10有明显的正相关和正相关趋势(r=0.758,P=0.000 1;r=0.346,P=0.056);体外实验发现,r IL-10或r TGF-β对T细胞CD107a或IFN-γ的分泌具有抑制作用。结论 HIV-1感染者T细胞分泌的抑制性细胞因子TGF-β水平增加,抑制T细胞功能的发挥,因此在临床抗病毒治疗中,应注意调节细胞因子的平衡,降低TGF-β的抑制作用。     

Pol as a target for antibody dependent cellular cytotoxicity responses in HIV-1 infection

Antibody-dependent cellular cytotoxicity (ADCC) may assist in preventing HIV or delaying disease progression. Most prior studies have analysed Env-specific ADCC responses. We hypothesized that effective ADCC-based immunity may target conserved internal viral proteins such as Pol. We analysed the ability overlapping Pol peptides to induce activation of NK cells via ADCC. We prospectively studied ADCC responses in 83 HIV+ subjects followed for 3 years. Pol peptides were commonly targeted by ADCC responses in these chronically infected subjects (in 32 of the 83 subjects). However, Pol-specific ADCC responses declined over time and did not correlate with delayed HIV progression, measured by either baseline CD4 T cells, CD4 T cell loss over time, baseline viral load or the need to start antiretroviral therapy. Although Pol is frequently targeted by ADCC in HIV+ subjects, the strength or specificity of Pol-specific ADCC responses needs to be modulated to be effective in delaying HIV progression.     

Anti-gamma interferon antibodies enhance the immunogenicity of recombinant adenovirus vectors

Vaccination for eliciting antigen-specific memory CD8(+) T cells may be facilitated by manipulating the pleiotropic effects of gamma interferon (IFN-γ). We assessed strategies for modulating the contribution of IFN-γ during the development of antigen-specific cytotoxic T lymphocyte (CTL) populations. We first showed that recombinant IFN-γ suppressed antigen expression in vitro from a recombinant adenovirus (rAd) vector in a dose-dependent manner and that addition of an anti-IFN-γ antibody (Ab) eliminated this suppression. Consistent with these in vitro findings, we found that HIV-1 envelope (Env)-specific CTL responses were higher in IFN-γ-knockout (GKO) mice than in wild-type mice following immunization with rAd. Since these observations suggested that IFN-γ might suppress rAd-induced CTL development, we assessed the ability of anti-IFN-γ Ab administration to augment rAd-elicited CTL in vivo. In fact, blockage of IFN-γ activity by monoclonal Ab administration was associated with elevated levels of interleukin 7 receptor alpha chain-positive (IL-7Rα(+)) Env-specific CTL populations postboost. These observations illustrate the utility of an anti-IFN-γ Ab for potentiating rAd immunizations to effect quantitative and qualitative changes in the effector and memory CTL populations.     

Increased expression of suppressor of cytokine signaling-1 (SOCS-1): A mechanism for dysregulated T helper-1 responses in HIV-1 disease

Maintenance of Th1 responses and dendritic cell (DC) functions are compromised in HIV-1 infected individuals. To better understand these immune abnormalities, we developed an HIV-1 transgenic (Tg) rat. We report that Tg DCs induce elevated levels of SOCS-1 and secrete decreased IL-12p40 and elevated levels of IL-10 following TLR-4 stimulation by LPS. This leads to further induction of SOCS-1 by IL-10 and decreased IFN-γ-mediated induction of interferon response factor (IRF)-1 and IL-12Rβ1 expression in CD4+ T cells and to decreased IL-12-induction of IFN-γ production by Th1 polarized T cells. We also show that SOCS-1 is elevated in CD4+ T cells from HIV-1 infected progressors, and is correlated with defective induction of IRF-1 following IFN-γ stimulation, compared with healthy controls and HIV-1 natural viral suppressor (NVS) patients. These results suggest a link between high levels of SOCS-1, defects in innate immunity and adaptive Th1 responses that may be reflected in the loss of Th1 immune competence observed with AIDS patients.     

Cross-Clade-Specific Cytotoxic T Lymphocytes in HIV-1-Infected Children

We studied cytotoxic T lymphocyte (CTL) cross-reactivity between human immunodeficiency virus type 1 (HIV-1) subtypes within a group of infants infected with either HIV-1 B or non-B clade. Fifteen children were infected with a clade B virus. Nine were infected with non-B virus, including two clade A, four clade D, two clade F, and one clade G. CTL activities fromin vitroactivated peripheral blood mononuclear cells were tested against autologous cell line infected with recombinant vaccinia viruses encoding for Env, Gag, Pol, or Nef proteins from a clade A or B isolate. HIV-1-specific CTL elicited from infection with clade B virus could lyse targets expressing clade A proteins, and vice versa. In infants with positive CTL responses, cross-clade recognition was predominant and was detected within 88% of the Pol, 83% of the Nef, 67% of the Gag, and 55% of the Env responders. Longitudinal studies showed that CTL cross-reactivity to both B and A targets was stable for several years. Elicitation of CTL reactivities capable of elimination of virus-infected cells is an important goal for the development of an efficient AIDS vaccine. The significant cross-reactivity of CTL shown in this study supports the concept that vaccines developed using a single-clade immunogen may be applicable to induce broadly reactive T cell responses.     

Human immunodeficiency virus type-1-specific immune responses induced by DNA vaccination are greatly enhanced by mannan-coated diC14-amidine

Use of mannan-coated N-t-butyl-N′-tetradecyl-3-tetradecylamino-propion-amidine (diC14-amidine) as an adjuvant for a DNA vaccine encoding glycoprotein 160 of human immunodeficiency virus type-1 (HIV-1) enhanced the antigen-specific immune responses. The role of interferon-γ (IFN-γ) and interleukin-12 in the mechanism of adjuvant action was also evaluated. Coating of diC14-amidine with mannan significantly augmented the HIV-specific delayed-type hypersensitivity reaction induced by the immunogenic DNA. HIV-1-specific cytotoxic T lymphocyte activity was also markedly enhanced by the mannan-diC14-amidine cocktail. An immunomodulatory effect of this cocktail was inhibited by treatment with anti-IFN-γ monoclonal antibody in vivo, which suggests that IFN-γ plays an important role in inducing cell-mediated immunity by the DNA vaccine containing this adjuvant. The results of both antigen-specific immunoglobulin isotype analysis and cytokine measurement showed that the immunogenic DNA incorporated into mannan-coated diC14-amidine elicits Th1-biased immune responses.