含癌胚抗原片段的重组腺相关病毒转染树突状细胞疫苗的体外杀伤作用

目的：观察研究人外周血单核细胞来源的树突状细胞（DC）转染含癌胚抗原（CEA）片段的重组腺相关病毒后所诱导的特异性T细胞对直肠癌细胞株LOVO和SW480的体外杀伤作用。方法：抽取HLA表型为A11的健康志愿者外周血，分离单核细胞，体外培养，使用含CEA片断的重组腺相关病毒转染未成熟DC，诱导特异性T细胞。检测体外培养的DC和CTL活性，并使用MTT法检测细胞毒性T细胞（CTL）对LOVO细胞的杀伤作用。结果：转染或未转染的体外培养的成熟DC高表达CD40、CD86、IL-12，诱导的细胞毒性T细胞高表达IFN-γ；转染后DC诱导特异性细胞毒性T细胞可有效识别并杀伤HLA-A11阳性的LOVO细胞。结论：重组腺相关病毒转染DC，不明显改变DC表型和刺激淋巴细胞增殖、分化功能，可诱导自体细胞毒性T细胞增殖，含CEA片断的腺相关病毒转染DC诱导自体细胞毒性T细胞对LOVO细胞有明显杀伤作用，DC疫苗可以作为直肠癌患者免疫治疗的有效补充。     

用于包装腺相关病毒293细胞的培养

背景:腺相关病毒作为一种主要的基因工程载体,已被广泛应用。但腺相关病毒是缺陷性病毒,需要包装细胞提供E1蛋白。腺相关病毒293细胞作为重要的腺相关病毒特异性包装细胞,能反式产生E1,但腺相关病毒293细胞娇嫩,培养困难,生物学特性易发生改变。因此,有必要建立一种腺相关病毒293细胞的培养方案以满足基因工程的需要。目的:建立一种体外培养腺相关病毒293细胞的方法。设计:开放性实验。单位:华中科技大学同济医学院附属同济医院神经内科。材料:腺相关病毒293细胞株购于Stratagene公司。高糖型DMEM粉(Gibco公司),AAV Helper-Free系统三质粒(Stratagene公司)。方法:实验于2006-10/2007-04在武汉同济医院神经内科实验室完成。在体外将腺相关病毒293细胞复苏,用高糖型DMEM生长培养基培养,当细胞单层融合度达到50%时传代和冻存,并倒置显微镜下观察细胞的生长状态,记录生长曲线。荧光倒置显微镜下观察,根据腺相关病毒293细胞在共转染腺相关病毒系统三质粒后以及被腺相关病毒上清感染后能否激发出绿色荧光,鉴定其包装腺相关病毒的生物学特性。主要观察指标:①腺相关病毒293细胞形态学观察。②生长曲线。③腺相关病毒包装。结果:①倒置显微镜下显示,腺相关病毒293细胞贴壁生长良好,呈现不规则的多角形,胞浆透亮,胞核隐约可见。②生长曲线显示,细胞传代后第1天为生长适应期,2～5d为生长活跃期,6d后细胞进入生长平台期。③荧光倒置显微镜下观察到,腺相关病毒293细胞激发绿色荧光,共转染腺相关病毒系统三质粒成功。腺相关病毒293细胞被腺相关病毒上清感染后激发出绿色荧光,腺相关病毒包装成功。结论:本实验的培养方法简单有用,培养的腺相关病毒293细胞可保持良好的腺相关病毒包装功能。     

腺相关病毒介导人血管内皮生长因子165基因转染后人骨髓基质细胞的成骨分化

背景:现阶段诱导骨髓基质细胞分化成骨的方法大致分为在化学药物作用、细胞因子作用以及转基因作用下的分化等.目的:观察腺相关病毒介导人血管内皮生长因子165基因转染对人骨髓基质细胞成骨能力的影响.设计、时间及地点:细胞学体外观察,于2008-03/12在郧阳医学院附属人民医院临床研究所和骨关节科完成.材料:人骨髓基质细胞取自健康成年男性自愿者.人血管内皮生长因子165基因重组腺相关病毒、β半乳糖酐酶基因重组复制缺陷性腺相关病毒由课题组前期构建.方法:抽取健康志愿者髂前上棘骨髓,采用全骨髓法分离培养人骨髓基质细胞.体外扩增纯化后取50%融合的P2代细胞,随机分为4组:腺相关病毒介导人血管内皮生长因子组向细胞培养液中加入人血管内皮生长因子165基因重组腺相关病毒1×1010OPU/mL,孵育24 h后换为普通完全培养液继续培养.β半乳糖酐酶基因重组腺相关病毒组加入半乳糖酐酶基因重组复制缺陷性腺相关病毒,其余处理与前组相同.阳性对照组向培养液中添加地塞米松、抗坏血酸和β-甘油磷酸钠.空白对照组仅加入普通完全培养液,不进行特殊处理.主要观察指标:全自动生化分析仪检测培养上清碱性磷酸酶活性,免疫组化染色观察血管内皮生长因子的表达,Von Kossa染色检测人骨髓基质细胞中骨胶原结节形成.结果:处理后2周,腺相关病毒介导人血管内皮生长因子组与阳性对照组的培养上清碱性磷酸酶活性基本相似(P>0.05),而β半乳糖酐酶基因重组腺相关病毒组、空白对照组的培养上清碱性磷酸酶活性均明显降低(P<0.01).血管内皮生长因子主要在骨髓基质细胞的胞浆内表达,腺相关病毒介导人血管内皮生长因子组阳性细胞数明显多于其他3组.腺相关病毒介导人血管内皮生长因子组和阳性对照组可见大量红色骨胶原结节形成,明显多于β半乳糖酐酶基因重组腺相关病毒组、空白对照组.结论:基因重组腺相关病毒人血管内皮生长因子165转染对人骨髓基质细胞成骨能力具有促进作用.     

人癌胚抗原重组痘苗病毒负荷树突状细胞体外诱导特异性T细胞免疫的研究

目的:研究人癌胚抗原重组痘苗病毒(CEA-rV)负荷脐血来源树突状细胞 (DC)后能否在体外诱导人癌胚抗原(CEA)特异性细胞毒性T淋巴细胞免疫。方法:将CEA-rV负荷脐血单核细胞来源的DC后用于激发同源的T细胞, 检测其对T细胞的增殖作用以及对CEA分泌性肿瘤细胞的杀伤活性,并与未经CEA-rV负荷的DC激发的T细胞进行比较。结果:经CEA-rV负荷的DC 激活的T细胞对CEA分泌性肿瘤细胞具特异性杀伤作用。结论:CEA-rV负荷的DC可以诱导CEA特异性T细胞活性。     

腺相关病毒介导绿色荧光蛋白基因体外转染人羊膜上皮细胞

背景:人羊膜上皮细胞易于获得,采集简单,是细胞移植和组织修复的理想种子细胞,目前国内外尚无关于标记、示踪体外培养的人羊膜上皮细胞的报道.目的:探讨腺相关病毒载体介导绿色荧光蛋白摹因对体外培养的人羊膜上皮细胞的转染效果.方法:取人羊膜标本,以胰蛋白酶消化法分离培养人羊膜上皮细胞,采用含绿色荧光蛋白的腺相关病毒进行转染,检测其转染效率.结果与结论:人羊膜上皮细胞可成功地在体外进行原代和传代培养,经含绿色荧光蛋白的腺相关病毒颗粒转染后,可稳定高效表达绿色荧光蛋白,转染效率达58%.     

9型腺相关病毒转染乳鼠心肌细胞的可行性及安全性

背景：9型腺相关病毒对心肌细胞具有更好的靶向转染,是目前研究基因治疗心脏疾病的理想载体。目的：探索9型腺相关病毒体外转染乳鼠心肌细胞的可行性及对乳鼠心肌细胞的毒性评估。方法：分离培养原代乳鼠心肌细胞,以携带荧光蛋白基因的9型腺相关病毒为载体,将分离纯化的乳鼠心肌细胞分为正常培养组、无病毒转染组、病毒转染组。结果与结论：第1周细胞搏动频率及百分率正常培养组和病毒转染组与无病毒转染组比较,差异无显著性意义（P〉0.05）,但正常培养组高于病毒转染组（P〈0.05）;3周后各组比较,差异无显著性意义（P〉0.05）。经9型腺相关病毒转染的心肌细胞24h开始有表达,4~6d荧光最强,3组细胞72h内不同时间点还原比率均接近于1.0。说明9型腺相关病毒能成功有效地转染乳鼠心肌细胞,对乳鼠心肌细胞无明显毒性作用。     

9型腺相关病毒转染乳鼠心肌细胞的可行性及安全性

背景:9型腺相关病毒对心肌细胞具有更好的靶向转染,是目前研究基因治疗心脏疾病的理想载体。目的:探索9型腺相关病毒体外转染乳鼠心肌细胞的可行性及对乳鼠心肌细胞的毒性评估。方法:分离培养原代乳鼠心肌细胞,以携带荧光蛋白基因的9型腺相关病毒为载体,将分离纯化的乳鼠心肌细胞分为正常培养组、无病毒转染组、病毒转染组。结果与结论:第1周细胞搏动频率及百分率正常培养组和病毒转染组与无病毒转染组比较,差异无显著性意义(P>0.05),但正常培养组高于病毒转染组(P<0.05);3周后各组比较,差异无显著性意义(P>0.05)。经9型腺相关病毒转染的心肌细胞24h开始有表达,4~6d荧光最强,3组细胞72h内不同时间点还原比率均接近于1.0。说明9型腺相关病毒能成功有效地转染乳鼠心肌细胞,对乳鼠心肌细胞无明显毒性作用。     

腺相关病毒及慢病毒载体对骨髓间充质干细胞基因转染效率的比较

目的比较腺相关病毒(AAV)载体和慢病毒(LV)载体在间充质干细胞(MSCs)基因转染中的效率。方法密度梯度离心法分离培养MSCs,HE 染色、Nestin 免疫荧光染色鉴定,BrdU 标记观察增殖情况。分别包装AAV 与LV 假病毒颗粒,并感染MSCs,通过β-gal 染色和绿色荧光蛋白检测,分别计算两者的转染效率。结果MSCs成功从骨髓分离。AAV载体介导的基因转染率为49.1%,LV载体的转染率为91.4% (P<0.01)。结论LV载体介导的基因转染方法转染效率更高。     

人外周血单核细胞来源树突状细胞转染重组腺相关病毒诱导特异性T细胞的效应

目的:观察人外周血单核细胞来源的树突状细胞转染含前列腺特异性抗原片段的重组腺相关病毒后,其所诱导的特异性T细胞对前列腺癌细胞株LNCaP和DU145的体外杀伤抑制作用。方法:实验于2006-05/10在南方医院肿瘤科生物室完成。①对象:HLA-A2基因亚型的健康自愿供血者1名,对本实验知情同意,实验经医院医学伦理委员会批准。作为靶细胞的前列腺癌细胞株LNCaP、DU145以及携带前列腺特异性抗原基因的重组腺相关病毒由美国阿肯色大学生物治疗中心刘勇教授惠赠。②实验方法:抽取HLA表型为A2的健康自愿供血者外周血50mL,Ficoll法分离单核细胞体外培养,磷酸盐缓冲液洗涤6孔板,收集悬浮细胞作为效应T细胞,贴壁细胞即为树突状细胞。向6孔板内加入粒细胞-巨噬细胞集落刺激因子和携带前列腺特异性抗原基因的重组腺相关病毒,第4天加入白细胞介素4,第6天加入肿瘤坏死因子α,至培养第7天收获悬浮细胞即为成熟的树突状细胞。③实验评估:应用流式细胞仪检测树突状细胞表面分子标记的表达。以ELISA法检测树突状细胞分泌白细胞介素12的含量。将成熟树突状细胞与效应T细胞分别按1:10、1:20、1:40进行共培养,将未经过树突状细胞共育的T细胞设置为空白对照组,ELISA法检测效应T细胞分泌干扰素γ的含量。LNCaP、DU145靶细胞分别与效应T细胞按效靶比5:1、10:1、20:1、40:1进行共培养,MTT法检测效应T细胞对两种靶细胞的杀伤作用。结果:①树突状细胞表面分子标记的表达:经携带前列腺特异性抗原基因的重组腺相关病毒致敏后的树突状细胞,培养8d后高表达CD83.CD40.HLA-DR,CD80,CD1a,CD86,分别为65.8%,66.0%,96.7%,70.0%,61.9%.79.0%。②树突状细胞释放白细胞介素12含量检测:与培养第1天比较,第7天成熟树突状细胞释放白细胞介素12的含量显著升高(P<0.05)。③效应T细胞释放干扰素γ含量检测:与空白对照组比较,树突状细胞:T细胞按1:10、1:20、1:40共培养后所释放的干扰素γ含量均明显升高(P<0.01.0.01,0.05),且随树突状细胞加入比例的提高有所增加。④效应T细胞的细胞毒性作用检测:效应T细胞可有效识别并杀伤HLA-A2阳性的LNCaP细胞,其抑制作用在效靶比为10:1、20:1、40:1时均显著强于DU145细胞株(P<0.01)。结论:经携带前列腺特异性抗原基因的重组腺相关病毒转染后的树突状细胞,其细胞表型和刺激淋巴细胞增殖、分化的功能无明显改变,可诱导自体效应T细胞增殖,该效应T细胞对LNCaP细胞具有明显杀伤作用。     

腺相关病毒2／1型载体转染大鼠骨髓间充质干细胞的实验研究

本研究探讨重组腺相关病毒2／1型（recombinantadeno—associatedvirus2／1,rAAV2／1）作为载体在不同转染复数、不同时间点转染大鼠骨髓间充质干细胞（bonemalTOWmesenchymalstemcells,BMMSC）的效率及对其生长的影响。用含有增强型绿色荧光蛋白（enhancedgreenfluorescentprotein,EGFP）报告基因的rAAV2／1（rAAV2／1-EGFP）,以感染复数（multiplicityofinfection,MOI）分别为1×10^4、1×10^5、1×10^6转染体外培养的大鼠骨髓间充质干细胞,在3、7、14天时荧光显微镜下观察EGFP的表达,检测子代细胞的活力、增殖倍数、分化情况．以评估rAAV2／1对BMMSC存活、增殖、分化能力的影响。应用流式细胞仪检测rAAV2／1-EGFP对BMMsC的转染效率及荧光指数（fluorescenceindexnumber,FU。结果表明：转染24小时后即可观察到BMMSC发出的绿色荧光,荧光强弱不一,随着时间的延长,荧光的强度逐渐增强,7天后达到稳定的状态;在3、7、14天时不同MOIrAAV2／1-EGFP转染BMMSC的活力、增殖倍数、分化能力无明显变化（P〉0．05）;在同一感染复数时,7天比3天和14天比7天的增殖倍数显著增强（P〈0．01）。流式细胞仪检测显示,rAAV2／1-EGFP转染BMMSC的转染率和荧光指数随着MOI增加（1×10^4、1×10^5、1×10^6）和培养时间（3、7、14天）的延长而有不同程度的增加（P〈0．05）。结论：rAAV2／1-EGFP能有效地转染BMMSC,随转染复数的增加和短期内随转染时间的延长,转染率和荧光指数明显增加。在转染过程中rAAV2／1-EGFP对细胞的活力、生长无影响。对于改造BMMSC,rAAV2／1是一种有效的基因转移载体。     

A histone deacetylase inhibitor enhances recombinant adeno-associated virus-mediated gene expression in tumor cells.

The transduction of cancer cells using recombinant adeno-associated virus (rAAV) occurs with low efficiency, which limits its utility in cancer gene therapy. We have previously sought to enhance rAAV-mediated transduction of cancer cells by applying DNA-damaging stresses. In this study, we examined the effects of the histone deacetylase inhibitor FR901228 on tumor transduction mediated by rAAV types 2 and 5. FR901228 treatment significantly improved the expression of the transgene in four cancer cell lines. The cell surface levels of alpha v integrin, FGF-R1, and PDGF-R were modestly enhanced by the presence of FR901228. These results suggest that the superior transduction induced by the HDAC inhibitor was due to an enhancement of transgene expression rather than increased viral entry. Furthermore, we characterized the association of the acetylated histone H3 in the episomal AAV vector genome by using the chromatin immunoprecipitation assay. The results suggest that the superior transduction may be related to the proposed histone-associated chromatin form of the rAAV concatemer in transduced cells. In the analysis with subcutaneous tumor models, strong enhancement of the transgene expression as well as therapeutic effect was confirmed in vivo. The use of this HDAC inhibitor may enhance the utility of rAAV-mediated transduction strategies for cancer gene therapy.     

Potential long-term inhibition of ocular neovascularisation by recombinant adeno-associated virus-mediated secretion gene therapy

Neovascularisation (NV) within the eye often results in visual loss. Vascular endothelial growth factor (VEGF) has been implicated in the development of ocular NV. Previous studies have shown that VEGF antagonists successfully suppressed retinal and choroidal NV in animal models. However, the systemic approach and transient nature of the delivery systems used in these studies hinder therapeutic application. To achieve stable and localised ocular anti-angiogenic therapy, we explored the use of recombinant adeno-associated virus (rAAV)-mediated secretion gene therapy (SGT). In this study, we generated a rAAV vector encoding soluble VEGF receptor 1, sFlt-1 (AAV-CMV.sflt) and determined its ability to inhibit cautery-induced corneal NV and laser-induced choroidal NV. Delivery of AAV-CMV.sflt into the anterior chamber resulted in transgene expression in the iris pigment epithelium and corneal endothelium, which reduced the development of corneal NV in the stroma of cauterised rats by 36% compared with cauterised control groups (P = 0.009). Subretinal delivery of AAV-CMV.sflt near the equator of the eye also suppressed choroidal NV at the laser lesions around the optic nerve by 19% (P = 0.002), indicating that there was diffusion of the secreted anti-angiogenic protein across the retina. Both results suggest that the long-term suppression of ocular NV is possible through the use of stable rAAV-mediated SGT.     

Augmentation of antitumor activity of a recombinant adeno-associated virus carcinoembryonic antigen vaccine with plasmid adjuvant

Recombinant adeno-associated virus 2 (rAAV) vectors have been successfully used for sustained expression of therapeutic genes. The potential of using rAAV as a cancer vaccine vector and the impact of a bacterial plasmid adjuvant on this activity were investigated. C57BL/6 mice received a single intramuscular injection of rAAV expressing the human tumor-associated antigen, carcinoembryonic antigen (CEA). Three weeks later, when CEA expression was optimal, a bacterial plasmid containing methylated DNA motifs was injected into the same muscle. Mice were challenged 1 week later with syngeneic MC38 tumor cells stably expressing CEA. Immunization with rAAV-CEA alone resulted in sustained transgene expression and the elicitation of a humoral immune response to CEA. Cellular immune response, however, was weak, and tumor protection was not significant. In contrast, immunization with rAAV-CEA and the plasmid adjuvant resulted in stronger cellular immune response to CEA and tumor protection. The addition of plasmid adjuvant increased both myeloid dendritic cell recruitment in situ and CEA-specific T-helper-1-associated immune response. These data indicate that robust rAAV transgene expression of a tumor antigen followed by transient plasmid delivery to recruit and activate dendritic cells is an effective method of eliciting antitumor cellular immune responses.     

Elastin-like polypeptide matrices for enhancing adeno-associated virus-mediated gene delivery to human neural stem cells

The successful development of efficient and safe gene delivery vectors continues to be a major obstacle to gene delivery in stem cells. In this study, we have developed an elastin-like polypeptide (ELP)-mediated adeno-associated virus (AAV) delivery system for transducing fibroblasts and human neural stem cells (hNSCs). AAVs have significant promise as therapeutic vectors because of their safety and potential for use in gene targeting in stem cell research. ELP has been recently employed as a biologically inspired 'smart' biomaterial that exhibits an inverse temperature phase transition, thereby demonstrating promise as a novel drug carrier. The ELP that was investigated in this study was composed of a repetitive penta-peptide with [Val-Pro-Gly-Val-Gly]. A novel AAV variant, AAV r3.45, which was previously engineered by directed evolution to enhance transduction in rat NSCs, was nonspecifically immobilized onto ELPs that were adsorbed beforehand on a tissue culture polystyrene surface (TCPS). The presence of different ELP quantities on the TCPS led to variations in surface morphology, roughness and wettability, which were ultimately key factors in the modulation of cellular transduction. Importantly, with substantially reduced viral quantities compared with bolus delivery, ELP-mediated AAV delivery significantly enhanced delivery efficiency in fibroblasts and hNSCs, which have great potential for use in tissue engineering applications and neurodegenerative disorder treatments, respectively. The enhancement of cellular transduction in stem cells, as well as the feasibility of ELPs for utilization in three-dimensional scaffolds, will contribute to the advancement of gene therapy for stem cell research and tissue regenerative medicine.     

Immune responses to adeno-associated virus and its recombinant vectors

Recombinant adeno-associated virus (rAAV) vectors have emerged as highly promising for use in gene transfer for a variety of reasons, including lack of pathogenicity and wide host range. In addition, all virus-encoded genes have been removed from standard rAAV vectors, resulting in their comparatively low intrinsic immunogenicity. For gene replacement strategies, transgenes encoded by rAAV vectors may induce less robust host immune responses than other vectors in vivo. However, under appropriate conditions, host immune responses can be generated against rAAV-encoded transgenes, raising the potential for their use in vaccine development. In this review, we summarize current understanding of the generation of both undesirable and beneficial host immune responses directed against rAAV and encoded transgenes, and how they might be exploited for optimal use of this promising vector system.     

Light-activated gene transduction of recombinant adeno-associated virus in human mesenchymal stem cells

Deficiencies in skeletal tissue repair and regeneration lead to conditions like osteoarthritis, osteoporosis and degenerative disc disease. While no cure for these conditions is available, the use of human bone marrow derived-mesenchymal stem cells (HuMSCs) has been shown to have potential for cell-based therapy. Furthermore, recombinant adeno-associated viruses (rAAV) could be used together with HuMSCs for in vivo or ex vivo gene therapy. Unfortunately, the poor transduction efficiency of these cells remains a significant obstacle. Here, we describe the properties of ultraviolet (UV) light-activated gene transduction (LAGT) with rAAV in HuMSCs, an advance toward overcoming this limitation. Using direct fluorescent image analysis and real-time quantitative PCR to evaluate enhanced green fluorescent protein (eGFP) gene expression, we found that the optimal effects of LAGT with limited cytotoxicity occurred at a UV dose of 200 J/m(2). Furthermore, this UV irradiation had no effect on either the chondrogenic or osteogenic potential of HuMSCs. Significant effects of LAGT in HuMSCs could be detected as early as 12 h after exposure and persisted over 21 days, in a time and energy-dependent manner. This LAGT effect was maintained for more than 8 h after irradiation and required only a 10-min exposure to rAAV after UV irradiation. Finally, we show that the production of secreted TGFbeta1 protein from rAAV-TGFbeta1-IRES-eGFP infected to HuMSCs is highly inducible by UV irradiation. These results demonstrate that LAGT combined with rAAV is a promising procedure to facilitate gene induction in HuMSCs for human gene therapy.     

Prevention and treatment of experimental autoimmune encephalomyelitis with recombinant adeno-associated virus-mediated alpha-melanocyte-stimulating hormone-transduced PLP139-151-specific T cells

The aim of this study was to investigate the immunomodulatory effects and mechanism of action of alpha-melanocyte-stimulating hormone (alpha-MSH) gene modified proteolipid protein (PLP) 139-151-specific T cells (T(PLP-alpha-MSH)) in the SJL mouse model of experimental autoimmune encephalomyelitis (EAE). PLP139-151-specific T cells (T(PLP) cells) were transduced with a recombinant adeno-associated virus 2 (rAAV2) encoding alpha-MSH. After activation with PLP139-151 in vitro, T(PLP-alpha-MSH) cells secreted high levels of alpha-MSH and also demonstrated an altered Th1-like cytokine pattern as well as a high frequency of CD4(+)CD25(+)Treg cells. Transfer studies showed that T(PLP-alpha-MSH) cells could suppress the induction of adoptive transfer EAE. More importantly, our studies demonstrated that T(PLP-alpha-MSH) cells had preventive and therapeutic effect on active relapse-remitting EAE (REAE) in an antigen-inducible manner. Suppression of REAE by T(PLP-alpha-MSH) cells was associated with a general reduction of inflammatory central nervous system (CNS) infiltrates, a pronounced decrease in Th1 cytokines and chemokines expression and an increase in Th2 cytokines. These data strongly suggested that local delivery of alpha-MSH by rAAV2-mediated alpha-MSH-transduced PLP139-151-specific T cells (T(PLP-alpha-MSH)) would be a desirable new approach to the treatment of autoimmune disease in the CNS.