Ad5F35-LMP2重组腺病毒修饰DC体外诱导特异性T细胞免疫的研究

目的 了解含有EB病毒潜伏膜蛋白2的非复制型重组腺病毒(AdSF35-LMP2)修饰的DC能否在体外诱导LMP2特异性细胞毒性T淋巴细胞免疫.方法 人外周血单个核细胞在细胞因子诱导下生成树突状细胞,Ad5F35-LMP2感染树突状细胞后激发同源的T细胞,MTT法检测其对T细胞的增殖作用,及激活的特异性CTL对表达LMP2的人CNE-2细胞的特异性杀伤效应.结果Ad5F35-LMP2能有效感染树突状细胞.其激活的特异性CTL对CNE-2细胞有特异性杀伤活性,与对照组相比差异有统计学意义(P<0.01).结论 重组腺病毒Ad5F35-LMP2感染的DC可以有效的诱导产生EBV-LMP2特异性细胞毒效应.     

人巨细胞病毒pp65核酸疫苗的构建、表达与动物免疫效应

构建真核重组表达质粒PVAX1-pp65,通过对其表达产物的鉴定和免疫小鼠实验,探讨PVAX1-pp65载体对诱导免疫应答的效果及方式。用已构建的原核表达载体pp65-pet32a,经酶切后与DNA疫苗载体PVAX1连接,构建HCMVpp65核酸疫苗(PVAX1-pp65)。用脂质体法将其转染293细胞,经间接免疫荧光、免疫印迹试验来验证其表达的产物。同时,免疫小鼠后取其脾脏细胞,经流式细胞仪检测其CD4+和CD8+T细胞;并利用MTT法测定免疫小鼠的T细胞对ConA和重组pp65蛋白刺激后的增殖活性。结果显示构建的真核表达载体PVAX1-pp65,经测序验证其序列正确。体外转染实验结果表明转染重组质粒的细胞胞浆内呈现与特异性pp65单克隆抗体反应的颗粒状荧光产物,免疫印迹试验也显示重组质粒转染的细胞裂解物中有pp65蛋白条带。另外,免疫小鼠脾CD8+T细胞的含量明显高于对照组;免疫鼠脾细胞对重组pp65抗原蛋白的刺激后增殖反应明显。综上结果证实,成功地构建了HCMVpp65核酸疫苗,并能有效地表达,表达的蛋白具有良好的免疫原性和免疫反应性。HCMVpp65DNA疫苗可诱导小鼠产生针对HCMV的特异性细胞免疫应答,可作为一种有应用前景的核酸疫苗进一步深入研究。     

人癌胚抗原重组痘苗病毒转染树突状细胞体外诱导的抗肿瘤免疫

目的：研究人癌胚抗原重组痘苗病毒（rV-CEA)转染外周血树突状细胞（DC）后在外体诱导的抗CEA分泌性肿瘤免疫。方法：分离晚期结肠癌患者的外周血单核细胞，在体外用人重组粒－巨噬细胞集落刺激因子（GM－CSF）及白细胞介素4（IL－4）培养成DC，再用rV-CEA转染DC后激发自体T细胞，观察其体外激发自体T细胞的增殖能力及其诱导的细胞毒性T淋巴细胞（CTL）对自体CEA分泌性肿瘤细胞的杀伤活性，并与野生型痘苗病毒（W－VV）及无病毒转染的DC所激发的T细胞进行比较。结果：经rV-CEA转染的DC能显著刺激自体T细胞的增殖，其激活的T细胞对CEA分泌性自体肿瘤细胞具有特异性杀伤作用。结论：rV-CEA转染的DC可以诱导体CEA分泌性肿瘤免疫。     

巨细胞病毒感染对人胚肺成纤维细胞增殖及凋亡的影响

目的探讨人巨细胞病毒（human cytomegalovirus,HCMV）感染对宿主细胞增殖及凋亡的影响。方法用HCMV AD169感染人胚肺成纤维细胞（human embryonic lung fibroblast cells,HEL）,倒置显微镜观察不同感染时间细胞病变,采用MTT法检测HCMV感染对HEL细胞增殖的抑制作用,同时采用流式细胞术检测HCMV感染细胞对照组细胞凋亡指数。结果在HCMV感染48h内,细胞增殖及凋亡指数与细胞对照组无明显差异。自HCMV感染72h后,细胞增殖明显受抑制,凋亡指数明显增高,细胞病变逐渐加重。结论在HCMV感染早期,对宿主细胞的增殖及凋亡影响不明显,在感染后期,HCMV通过抑制宿主细胞增殖,加重细胞病变,促进感染细胞的凋亡而发挥致病作用。     

人巨细胞病毒感染与宿主细胞趋化因子分泌的相关性研究

目的 研究人巨细胞病毒(HCMV)对人胚肺成纤维细胞(HEL)分泌趋化因子白细胞介素-8(IL-8)及正常T细胞表达和分泌受活化调节的蛋白(RANTES)的影响,以探讨HCMV感染所致免疫病理改变的具体机制.方法 用RT-PCR法检测IL-8 mRNA和RANTES mRNA的表达,用双抗体夹心法(ELISA)测定IL-8和RANTES蛋白的分泌.结果 HEL细胞感染HCMV后,IL-8无论从mRNA水平还是蛋白水平,均随着感染时间的延长,表达逐渐增加,至感染72 h,IL-8 mRNA约为对照组的12倍,蛋白约为对照组的9倍.RANTES mRNA在感染后8 h可测出,24 h达到高峰,其后虽有下降,但仍维持较高水平;RANTES蛋白分泌在感染后24 h达到高峰,随后急剧下降,至72 h基本无表达.结论 HCMV感染HEL细胞诱导IL-8基因转录及IL-8蛋白分泌增加.HCMV感染HEL细胞可下调RANTES的分泌.     

巨细胞病毒感染与粘附分子-1基因转录水平的实验研究

目的研宄人巨细胞病毒(human cytomegalovirus,HCMV)感染人胚肺成纤维细胞(human embryonic lung,HEL)后粘附分子-1(ICAM-1)在基因转录水平的表达,探讨HCMV感染的发病机制.方法采用RT-PCR技术研究细胞ICAM-1-1在基因转录水平的表达.结果感染巨细胞病毒后ICAM-1的表达上调,而UV灭活的CMV不能诱导ICAM-1的上调,中药金叶败毒制荆与更昔洛韦(Ganciclovir,GCv)不能阻止病毒诱导的ICAM-1的上调.MEK特异性抑制子PD98059可加强ICAM-1的上调作用.结论细胞ICAM-1-1在转录水平的上调可能是感染病毒的直接作用,MEK特异性抑制子PD98059加强ICAM-1上调作用.     

TNFα和IL-10在巨细胞病毒感染人胚肺成纤维细胞中的作用

目的:研究TNFα和IL-10对人巨细胞病毒(HCMV)感染人胚肺成纤维细胞(HEL)的影响,以及感染细胞产生TNFα的变化,探讨有关细胞因子在HCMV感染免疫中的作用。方法:用不同浓度的TNFα和IL-10作用于HEL,24h后感染病毒,研究TNFα和IL-10对HCMV感染HEL的影响。用HCMV感染HEL,感染后(4、24、48、72、96h)分别收集培养上清液,用ELISA法检测TNFα含量。结果:在病毒感染前,中、高浓度TNFα或低、中浓度IL-10可抑制HCMV在HEL内的增殖。HCMV感染HEL后,细胞产生TNFα的量无明显改变。结论:TNFα和IL-10在HCMV感染免疫过程中起作用。     

人黑色素瘤抗原-3冲击的树突状细胞诱导抗肿瘤免疫应答

目的:观察经MAGE-3蛋白抗原冲击的树突状细胞在体外诱导抗肿瘤免疫应答的能力。方法:用粒-巨噬细胞集落刺激因子和白介素-4从人外周血分化、诱导树突状细胞,经MAGE-3蛋白冲击后,与T淋巴细胞共培养7d,收集T淋巴细胞进行免疫应答及肿瘤细胞杀伤试验。结果:与MAGE-3冲击后的树突状细胞共培养的T淋巴细胞在体外能有效地杀伤MAGE-3阳性的靶细胞。结论:经MAGE-3蛋白抗原冲击的树突状细胞,在体外能有效提呈抗原,激活抗原特异性CTL,诱导特异性抗肿瘤免疫应答。     

NF-κB在人巨细胞病毒感染诱导宿主细胞增殖、凋亡中的作用

目的:探讨人巨细胞病毒(HCMV)是否通过激活核转录因子(NF-κB)调控宿主细胞增殖与凋亡。方法:用HCMVAD169株感染人胚肺成纤维细胞(HEL),采用免疫组化和Westernblot方法检测宿主细胞NF-κB和Bcl-2蛋白的表达与I-κBα的变化,应用MTT方法观察细胞的增殖活性,同时用流式细胞术检测细胞凋亡指数。结果:HCMV感染后48h细胞核表达NF-κB蛋白最多,24hI-κBα降到最低,120hNF-κB失活,bcl-2的表达与NF-κB的活性改变一致。HCMV感染在72h前抑制宿主细胞凋亡,促进细胞增殖,在120h可诱导宿主细胞凋亡。结论:NF-κB在HCMV感染诱导宿主细胞增殖与凋亡中起作用,与HCMV疾病的发生发展有关。     

NF-κB在人巨细胞病毒感染诱导宿主细胞增殖、凋亡中的作用

目的：探讨人巨细胞病毒(HCMV)是否通过激活核转录因子(NF—κB)调控宿主细胞增殖与凋亡。方法：用HCMV AD169株感染人胚肺成纤维细胞(HEL),采用免疫组化和Westem blot方法检测宿主细胞NF—κB和Bel-2蛋白的表达与I-κBα的变化,应用MTT方法观察细胞的增殖活性,同时用流式细胞术检测细胞凋亡指数。结果：HCMV感染后48h细胞核表达NF—κB蛋白最多,24hI-κBα降到最低,120hNF—κB失活,bcl-2的表达与NF—κB的活性改变一致。HCMV感染在72h前抑制宿主细胞凋亡,促进细胞增殖,在120h可诱导宿主细胞凋亡。结论：NF—κB在HCMV感染诱导宿主细胞增殖与凋亡中起作用,与HCMV疾病的发生发展有关。     

Characterization of antigen-specific repertoire diversity following in vitro restimulation by a recombinant adenovirus expressing human cytomegalovirus pp65

Human cytomegalovirus (HCMV) and adenovirus cause significant morbidity and mortality in immunocompromised hosts undergoing allogeneic stem cell transplantation. We have previously established a procedure for the generation of polyclonal CTL with specificity against adenovirus and HCMV using a recombinant adenovirus encoding the HCMV pp65 protein (RAdpp65). However, specific CTL expanded after in vitro culture steps were subjected to several in vitro restimulations and, depending on the protocol adopted, this could lead to a selection bias, compromising the clinical benefit. To determine which part of the memory repertoire is selected after in vitro restimulation, we have followed the specificity and clonal composition of pp65-peptide-specific CD8(+) T cells in HLA-A*201 individuals before and after repeated in vitro restimulation of cells with RAdpp65, combining HLA tetrameric complexes and immunoscope analysis. Tetramer staining showed that, after in vitro restimulation, up to 60% of CD8(+) T cells were virus-specific. Immunoscope analysis showed that the predominant TCRBV diversity of pp65-specific clones was conserved, demonstrating that the memory repertoire was preserved all along the procedure. Altogether, these results suggest that the use of RAdpp65 to induce CMV- and adenovirus-specific CTL maybe appropriate for immunotherapy.     

K562细胞总RNA转染对人树突状细胞抗原提呈、成熟及功能影响的初步研究

探讨人的树突状细胞(dendriticcell,DC)体外经K562细胞株总RNA转染后,能否诱导出p210蛋白表达,并诱导特异性CTL,为DC疫苗的临床应用提供理论基础。自健康人浓缩白细胞制剂分离有黏附特性的单核细胞,经GM-CSF、IL-4培养5d后,获得未成熟的DC(imDC);体外以脂质体DOTAP或直接电穿孔转染K562细胞总RNA。抽提后即时以及转染24h后的DC内RNA进行RT-PCR检测,Westernblot分析p210蛋白表达,流式细胞仪检测,以及诱导CTL杀伤K562细胞功能检测等。结果显示,RT-PCR检测表明:DC经K562细胞总RNA转染后,细胞内出现Bcr-Abl的cDNA条带,24h后消失。Westernblot实验表明:转染24h后,开始表达p210特征性蛋白。与对照组相比,转染K562细胞总RNA的DC,在24h后CD80、CD83、CD86、HLA-DR等表面标志均不同程度表达增高,并可促进T细胞对K562的杀伤活性。该研究从多方面角度说明应用肿瘤总RNA负载DC来制备DC疫苗的可行性,提示改良的DC疫苗抗肿瘤可能的应用前景。     

Defective generation of killer cells against spontaneously Epstein-Barr virus (EBV)-transformed autologous B cells in a fatal EBV infection.

Killer cell activities were analysed in a 16-month-old boy with a sporadic form of fatal Epstein-Barr virus (EBV) infection, and compared with those in three patients with acute infectious mononucleosis (IM). We used spontaneously EBV-transformed autologous lymphoblastoid B cell lines (LCL) as target cells, because the results obtained with such targets can be expected to reflect most accurately the killer-versus-target reaction in vivo. The patient's fresh peripheral blood mononuclear cells (PBMC) had relatively high natural killer (NK) cell activity against K562 cells (128% of the control value), but they did not kill his autologous LCL. The patient's PBMC, unlike PBMC of acute IM, showed no cytotoxicity against Raji cells and autologous LCL after 5 days' culture in the presence of recombinant interleukin 2 (rIL-2), indicating defective generation of lymphokine-activated killer (LAK) cells. The patient's PBMC, unlike PBMC of acute IM, also could not induce cytotoxicity against autologous LCL when cocultured with mitomycin C-treated respective autologous LCL for 7 days. The addition of rIL-2 to the culture significantly restored their ability to generate cytotoxic T lymphocytes (CTL) against his LCL: the percent cytotoxicity value rose from 3.0% to 37.7%. With respect to this, the endogenous IL-2 production by the patient's PBMC was deficient. These results suggest that the defective EBV-selective CTL generation was due to deficient IL-2 production. The failure of the killer cells to eliminate EBV-infected cells seems to have been responsible for the patient's unusual course after primary EBV infection.     

转染肿瘤总RNA的DC疫苗诱导抗肝癌特异性免疫

目的：探讨转染人肝癌总RNA的树突状细胞(DC) 疫苗体外诱导特异性细胞毒性T淋巴细胞(CTL)的作用。 方法： 采用原发性肝癌（HCC）病人外周血单核细胞（PBMC），在粒/巨细胞集落刺激因子(GM-CSF)和白细胞介素-4(IL-4) 刺激下增殖分化为DC细胞；从人肝癌细胞中体外扩增肝癌RNA。以HCCRNA转染DC细胞，并与PBMC混合培养诱导扩增CTL。MTT法测定CTL的杀瘤活性。 结果： 转染HCCRNA 48 h后， DC表面分子CD83、CD86和HLA-DR表达明显增高。转染HepG-2细胞HCCRNA的DC和病人HCCRNA诱导的CTL对HepG-2细胞和病人HCC细胞的杀瘤活性均明显高于正常肝细胞RNA+DC、脂质体+DC、Opti-MEM+DC以及空白对照组；而对胃癌SGC-7901细胞无杀伤活性。 结论： 以肝癌RNA为肿瘤抗原，DC作为疫苗的抗原提呈细胞，体外冲击致敏DCs，能诱导肝癌特异性CTL。本研究为HCC术后复发和转移的防治提供一种可能有效的疫苗治疗方法。     

Cytotoxic T cell immunity to human cytomegalovirus glycoprotein B

Human cytomegalovirus (HCMV) is associated with significant morbidity and mortality following immunosuppression and in pregnancy. HCMV infection may be accompanied by acute disease but persists asymptomatically. Cytotoxic T lymphocytes (CTL) appear to be an important immune effector mechanism in maintaining the normal host-virus equilibrium. Glycoprotein B may be an important target for future subunit vaccines as it has been found to elicit both neutralising antibody and CTL responses. We therefore studied the ability of normal asymptomatic HCMV-seropositive individuals and women throughout pregnancy to determine the presence of HCMV and gB-specific CTL responses. CTL effector cells were induced by stimulation of peripheral blood mononuclear cells (PBMC) with AD169 HCMV-infected cells and gB-specific CTL were identified using chromium labeled, vac.gB-infected cells. In 7 HCMV-seropositive individuals, HCMV-specific CTL were identified. Three of the 7 individuals which lysed HCMV-infected cells lysed vac.gB-infected B cells. However, vac.gB-infected autologous fibroblasts, which only present MHC class I, were not killed. Using MHC class I single allele targets, no specific lytic response was observed, suggesting a MHC class II restricted CTL response. Flow cytometric analysis showed the gB-specific effector cell phenotype to be CD3+, CD4+, CD8−. In conclusion, a gB-specific CTL lytic response was identified in seropositive individuals which in most cases was MHC class II-restricted. © 1996 Wiley-Liss, Inc.     

Relative dominance of HLA-B*07 restricted CD8+ T-lymphocyte immune responses to human cytomegalovirus pp65 in persons sharing HLA-A*02 and HLA-B*07 alleles

CD8(+) T-cell responses to three human cytomegalovirus (CMV) pp65 epitopes were studied in panels of healthy seropositive HLA-A*02/HLA-B*07 individuals, and HLA-A*02 donors mismatched for HLA-B*07. The majority of the latter had significant responses to a HLA-A*02-restricted epitope within the CMV pp65 antigen. By contrast, the strongest responses to CMV in the first group were to HLA-B*07-restricted epitopes. Similar immunodominance of HLA-B*07 over HLA-A*02 was found in two immunocompromised HIV-infected HLA-A*02/HLA-B*07 patients, and in the reconstituting immune system of three stem cell transplant recipients. In vitro stimulation of peripheral blood mononuclear cells (PBMC) from two immunocompetent HLA-A*02/HLA-B*07 individuals indicated that cytotoxic T lymphocyte (CTL) precursors specific for both HLA-A*02 and HLA-B*07 restricted epitopes were present and could be expanded by stimulation with the cognate peptides. However, if stimulation was performed by antigen presenting cells infected with recombinant vaccinia expressing full-length native pp65, only HLA-B*07 epitope-specific cells were seen. In one patient the HLA-B*07 dominance was partially broken by using recombinant vaccinia expressing ubiquitinated pp65, suggesting that enhanced protein processing can reveal weaker immune responses. Our results indicate that CMV-specific cellular immune responses restricted by HLA-B*07 dominate those restricted by HLA-A*02 in both immunocompetent and immunocompromised individuals. This may have significant consequences for the design of epitope-specific vaccines.     

Analysis of viral proteins in human cytomegalovirus-infected cells during impaired lytic replication of herpes simplex virus

Herpes simplex virus (HSV) latency can be established in vitro following arrest of virus replication and survival of infected cells in culture. Human cytomegalovirus (HCMV) has been shown to interact with HSV, resulting in reactivation of latent HSV. In addition, impaired replication of superinfecting HSV occurs in HCMV-infected human cells. HCMV-infected human embryonic lung cells inhibit production of infectious HSV despite replication of HSV DNA at levels comparable to those in control cultures infected only with HSV. Using radioimmunoprecipitation techniques, we found that the synthesis of HSV type 1 proteins of the alpha, beta/gamma, and gamma kinetic classes was impaired during the restricted replication of HSV in HCMV-infected HEL cells. However, synthesis of the HSV beta protein ICP-8 and HCMV alpha and beta proteins was not significantly affected in superinfected cell cultures.     

WT1多肽致敏树突状细胞诱导杀伤K562细胞实验研究

目的：研究来自健康人外周血单个核细胞的树突状细胞（DC）负载WT1多肽抗原，体外诱导产生特异性细胞毒性T淋巴细胞（CTL）对K562细胞的杀伤作用。 方法： 应用重组人粒-巨噬细胞集落刺激因子(rhGM-CSF)、重组人白细胞介素4（rhIL-4）、重组人肿瘤坏死因子α（TNF-α）等细胞因子，自外周血单个核细胞诱导扩增，培养出DC，使DC负载WT1多肽抗原。实验分3组，WT1多肽致敏DC为实验组A，未致敏DC为实验组B，单纯自体淋巴细胞未加DC激活为对照组C，观察CTL对K562细胞的杀伤作用。 结果： 培养出具有典型特征的DC，体外能诱导强烈的同种异体混合淋巴细胞增殖反应。在效靶比为20∶1时，实验组A诱导的CTL对K562细胞的杀伤率为86.1%±26.8%；实验组B为47.1%±20.8%；对照组C为27.7%±15.3% (P＜0.05)。 结论： WT1多肽抗原致敏DC能促使CD8阳性淋巴细胞扩增，并诱导激活特异性CTL，对K562靶细胞具有明显的杀伤作用。     

人白细胞介素4诱导杀伤细胞的研究

人重组白细胞介素４（ｒｈＩＬ－４）在ＰＨＡ协同下，从人外周血单核细胞（ＰＢＭＣ）诱导出明显的ＬＡＫ活性，其对Ｋ５６２、Ｒａｊｉ细胞的杀伤力低于ＩＬ－２诱导者，对ＴＢＬ－Ｅ，ＰＨＡ活化的淋巴母细胞（ＰＨＡ－ｂｌａｓｔｓ）的杀伤力和ＩＬ－２诱导者相似。在ＰＨＡ介导的４小时５１Ｃｒ杀伤试验中，加入ＰＨＡ后，ＩＬ－４－ＬＡＫ对ＰＨＡ－ｂｌａｓｔｓ的杀伤力提高２．３倍，而ＩＬ－２－ＬＡＫ对ＰＨＡ－ｂｌａｓｔｓ的杀伤力无变化，提示ＩＬ－４主要诱导ＣＴＬ样活性，而ＩＬ－２主要诱导ＮＫ样活性，ＩＬ－４诱导效应ＣＴＬ的能力强于ＩＬ－２。我们的实验同时证实，在淋巴细胞活化的早期，ＩＬ－４抑制ＩＬ－２诱导的ＬＡＫ活性，淋巴细胞活化后，ＩＬ－４与ＩＬ－２有协同作用，增强ＩＬ－２诱导的ＬＡＫ活性。     

Immune evasion proteins gpUS2 and gpUS11 of human cytomegalovirus incompletely protect infected cells from CD8 T cell recognition

Human cytomegalovirus (HCMV) encodes four glycoproteins, termed gpUS2, gpUS3, gpUS6 and gpUS11 that interfere with MHC class I biosynthesis and antigen presentation. Despite gpUS2-11 expression, however, HCMV infection is efficiently controlled by cytolytic CD8 T lymphocytes (CTL). To address the role of gpUS2 and gpUS11 in antigen presentation during viral infection, HCMV mutants were generated that expressed either gpUS2 or gpUS11 alone without coexpression of the three other proteins. Fibroblasts infected with these viruses showed reduced HLA-A2 and HLA-B7 surface expression. Surprisingly, however, CTL directed against the tegument protein pp65 and the regulatory IE1 protein still recognized and lysed mutant virus infected fibroblasts. Yet, suppression of IE1 derived peptide presentation by gpUS2 or gpUS11 was far more pronounced. The results show that gpUS2 and gpUS11 alone only incompletely protect HCMV infected fibroblasts from CTL recognition and underline the importance of studying infected cells to elucidate HCMV immune evasion.