rAAV2-hGAD65重组载体的构建和功能检测

目的构建rAAV2-hGAD65重组载体,观察其体内外功能。方法应用RT-PCR的方法克隆hGAD65基因,与AAV载体连接得到重组载体(rAAV2-hGAD65)。包装重组腺相关病毒并检测病毒的滴度。体外感染成纤维细胞后,用免疫组织化学的方法检测GAD65在细胞中的表达水平,用高效液相色谱(HPLC)法检测培养上清中γ-氨基丁酸(GABA)的含量。在体实验中,向丘脑底核(STN)立体定位注射rAAV2-hGAD65后,用HPLC方法检测黑质网状部(SNr)中的GABA含量。结果应用RT-PCR方法成功地从人胚胎端脑组织中克隆出GAD65基因的cDNA,基因测序显示与基因库中人GAD65基因序列一致,亚克隆入AAV载体并包装后所得的病毒颗粒的滴度达到4.5×1011/ml。组织化学检测感染大鼠肺成纤维细胞的效率约为80%,HPLC检测培养上清中GABA的含量为(45.66±6.07)nmol/L。STN立体注射rAAV2-hGAD65后,在STN可以检测到hGAD65的表达,SNr区GABA的含量由原来的(5.66±1.07)nmol/g升高到(12.66±2.59)nmol/g。结论成功地克隆出了人GAD65基因,并构建了AAV重组载体。AAV病毒颗粒在体外能感染成纤维细胞并具有催化谷氨酸合成GABA的功能。在体内实验中,向STN注射rAAV2-hGAD65后,可以增加黑质网状部(SNr)中的GABA含量。     

用于IDDM基因治疗的rAAV2-GAD-Ig的研制

目的: 构建重组真核表达载体pSNAV- GAD -Ig[GAD- Ig融合基因是由小鼠GAD(glutamicaciddecarboxylase)基因插入到小鼠IgG3重链(Ig)基因的N端而成的 ], 制备含GAD- Ig融合基因cDNA的重组缺陷型腺相关病毒 -2 (rAAV2- GAD -Ig), 并探讨rAAV2所介导的GAD- Ig是否能诱导I型糖尿病(IDDM)动物模型 NOD(nonobesediabetic)小鼠产生特异性免疫耐受。方法: 从含GAD- Ig融合基因的中介载体BSSK(BSSK- GAD- Ig)中, 用PCR方法扩增目的基因片段, 并克隆入真核表达载体pSNAV中, 构建重组真核表达载体pSNAV- GAD Ig。以脂质体法将pSNAV GAD -Ig转染到rAAV2包装细胞BHK -21中, 产生rAAV2 -GAD- Ig。采用R-T PCR、Westernblot和ELISA法, 检测rAAV2- GAD -Ig感染的BHK- 21细胞中目的基因的表达。应用GAD抗原体外诱导特异性T细胞的二次应答, 来检测rAAV2所介导的GAD -Ig是否能诱导NOD小鼠产生特异性免疫耐受。结果: GAD- Ig目的基因已整合到靶细胞的基因组中, 并能以分泌形式表达目的蛋白GAD- Ig。将rAAV2 GAD- Ig肌注后, NOD小鼠能产生特异性免疫耐受。结论: 获得了可用于NOD小鼠治疗研究的rAAV2 GAD- Ig。     

大鼠GAD65重组腺病毒载体的构建和鉴定

目的构建大鼠GAD65重组腺病毒载体。方法将目的基因大鼠GAD65 cDNA亚克隆到穿梭质粒pShutile启动子CMV的下游,再通过I-CeuⅠ和PI-SceⅠ两个稀有酶切位点,将目的基因GAD65与腺病毒质粒DNA(pAdeno-X)进行体外连接,获得含目的基因GAD65重组腺病毒质粒DNA,后者经限制性内切酶PaeⅠ切割后,两端露出反向末端重复序列(rTR),利用脂质体转染293细胞,获得含目的基因重组腺病毒上清。PCR双引物检测含有目的基因GAD65的片段。结果在挑选的5个空斑中,有4个含GAD65 cDNA阳性重组腺病毒。GAD65重组腺病毒可感染293细胞并在293细胞内进行有效的复制。PCR双引物检测证明含有目的基因GAD65片段,表明利用体外连接法成功构建了含目的基因GAD65重组腺病毒转移载体。结论成功构建了GAD65重组腺病毒,为进一步研究GAD65重组腺病毒的功能提供了条件。     

rAAV2/1-Acrp30病毒的纯化、扩增与活性检测

目的 将大鼠脂联素基因(Acrp30)克隆到腺相关病毒(AAV)载体中,经包装、纯化、扩增后获得rAAV2/1-Aerp30病毒,并进行活性检测.方法 筛选阳性克隆获得pSNAV2.0-Acrp30,EcoR Ⅰ/Sal Ⅰ双酶切鉴定,并行测序.转染BHK21细胞,G418筛选培养,获得抗药克隆细胞株.HSV1-re/△UL2感染,包装此细胞株并收获病毒载体rAAV2/1-Acrp30.行DNA斑点杂交法测定病毒滴度,SDS-PAGE分析判断病毒纯度,Western blot法检测目的 蛋白脂联素在HEK293细胞中的表达活性.结果 PCR电泳及酶切鉴定表明,pSNAV2.0-Acrp30重组成功,基因测序显示装入pSNAV2.0质粒中的Acrp30基因正确.rAAV2/1-Acrp30病毒的大致滴度为1.0×1012μg/ml,HEK293细胞分泌蛋白浓度为50 ng/ml,病毒载体纯度在95%以上.结论 实验获得的脂联素病毒载体滴度高、感染性好,可试用于GK(Goto-Kakizaki)大鼠脂联素转基因治疗.     

腺相关病毒载体pAGX(+)的构建

目的构建腺相关病毒(AAV)载体并进行鉴定,以介导真核细胞的基因传递和表达.方法以基因重组技术构建AAV载体,用Southern杂交、狭缝杂交以及激光共聚焦显微镜等鉴定构建的AAV载体.结果成功地获得了重组AAV表达载体pAGX(+),藉报告基因EYFP鉴定pAGX(+),见pAEYFP经包装的重组AAV储存液的感染滴度达1.39×107TU(transmissionunit)/ml、复制滴度达1.94×1011颗粒/ml.Southern杂交表明EYFP基因获得成功拯救.rAAV/EYFP颗粒成功转导COS7细胞,EYFP获得表达,并整合入COS7细胞基因组,而藉质粒载体pEYFPCMV介导的转移,EYFP未能整合.结论成功地构建了一个AAV载体,并成功地介导了基因的转移、表达和整合.     

含HIV-1 gp120基因的重组腺相关病毒和重组腺病毒疫苗联合免疫的研究

目的 探讨含HIV-1 gp120基因的重组腺相关病毒(rAAV)和重组腺病毒(rAdV)疫苗在BALB／c小鼠中联合免疫的效果。方法 将密码子优化的HIV-1 gp120基因分别插入腺相关病毒(AAV)和腺病毒(AdV)载体质粒，构建含该基因的rAVV和rAdV载体疫苗。将两种疫苗以不同的联合方式免疫BALB／c小鼠，ELISA检测小鼠血清中的gp120特异性抗体，细胞内细胞因子染色法检测小鼠的特异性细胞毒性T淋巴细胞(CTL)应答。结果 两种重组病毒均可表达目的基因gp120；在小鼠体内两种重组病毒联合免疫可诱导特异性的CTL应答和血清1gG抗体反应，但用rAAV初免2次，再用rAdV加强3次所诱发的CTL和血清1gG反应最强。结论 rAAV和rAdV疫苗联合免疫可在小鼠体内诱导特异性的CTL应答和血清1gG抗体反应。     

腺相关病毒载体介导乳腺癌BA46基因转移的实验研究

目的　评价腺相关病毒 (AAV)为载体介导乳腺癌BA4 6基因转导树突状细胞 (DC)的可行性。方法　构建重组质粒d16 95 /BA4 6 p5/NeoSV40 (简称rAAV/BA4 6 /Neo) ,并制备该病毒。分离外周血单核细胞 (DC前体细胞 ) ,采用GM CSF、IL 4、TNF α诱导 ,以rAAV/BA4 6 /Neo病毒感染DC前体细胞 ,感染后 72h ,流式细胞仪检测rAAV/BA4 6 /Neo病毒感染效率及BA4 6表达情况 ,6d后 ,RT PCR分析BA4 6mRNA转录情况 ,PCR/Southernblot分析BA4 6基因染色体整合情况。结果　AAV成功介导BA4 6基因转导DC ,BA4 6在DC内良好表达 ,病毒基因整合入DC基因组内。结论　AAV载体成功介导BA4 6基因转导DC ,为以DC为基础的乳腺癌的基因治疗打下基础。     

重组色素上皮衍生因子对人视网膜微血管内皮细胞迁移及凋亡的影响

目的: 构建rAAV2-PEDF腺相关病毒,研究色素上皮衍生因子(PEDF)基因高表达对人视网膜微血管内皮细胞的作用。方法: 将PEDF基因克隆、重组到腺相关病毒载体pSNAV,得到的pSNAV-PEDF后转染BHK细胞,用含G418的培养基进行筛选,得到稳定转染pSNAV-PEDF的生产细胞系,用重组1型单纯疱疹病毒HSV1-rc/△UL2感染细胞进行病毒包装,纯化后得到高滴度rAAV2-PEDF 病毒颗粒。按照10⁵v.g./cell的剂量进行rAAV2-PEDF病毒转染,分别设空白和阴性对照,激光共聚焦显微镜下观察GFP阳性细胞,Western blotting检测PEDF蛋白表达。Boyden小室法观察细胞迁移情况,流式细胞术检测细胞凋亡情况。结果: 通过PCR、酶切及基因测序的方法,证实rAAV2-PEDF构建成功。转染病毒48 h后,激光共聚焦显微镜下观察可见GFP阳性细胞,Western blotting检测,实验组PEDF表达明显强于其它组。rAAV2-PEDF干预正常氧条件下人视网膜微血管内皮细胞,正常对照组凋亡细胞比例为2.10%±0.53%,rAAV2-GFP组为3.40%±0.62%,rAAV2-PEDF组为1.60%±0.47%,各组间无显著差异(P＞0.05)。rAAV2-PEDF干预低氧条件下人视网膜微血管内皮细胞,单纯CoCl₂组凋亡细胞比例为4.00%±0.55%,CoCl₂+rAAV2-GFP组为6.10%±0.71%,CoCl₂+rAAV2-PEDF组为40.00%±2.10%。rAAV2-PEDF组与其它2组相比,有显著差异(P<0.05)。细胞迁移计数显示,正常对照组为33.0±2.7,rAAV2-GFP组为35.0±3.6,rAAV2-PEDF组为12.0±2.1,rAAV2-PEDF组与其它2组相比,有显著差异(P<0.05)。结论: 成功构建了rAAV2-PEDF,转染人视网膜血管内皮细胞后PEDF可稳定表达。PEDF高表达可显著抑制人视网膜微血管内皮细胞迁移并可在低氧条件下诱导其凋亡。     

GAD67-GFP基因敲入小鼠黑质网状部神经元GABA与氯离子转运体KCC2和NKCC1的共存

为了观察谷氨酸脱羧酶67-绿色荧光蛋白(GAD67-GFP)基因敲入小鼠黑质网状部(SNr)内,表达GFP的GABA能神经元与一对功能相反的Cl-共转运体(K+-Cl-cotransporter2,KCC2;Na+-K+-Cl-cotransporter1,NKCC1)的共存情况,本研究分别运用原位分子杂交与免疫组织化学相结合以及GFP与KCC2或NKCC1免疫荧光染色相结合的双重标记方法,在光学显微镜和激光共聚焦显微镜下同时进行观察。结果显示:(1)SNr内95%以上的GFP阳性神经元同时表达KCC2 mRNA,而50%表达KCC2 mRNA的阳性神经元呈GFP阳性;(2)SNr内80%以上的GFP阳性神经元同时表达NKCC1 mRNA,约35%表达NKCC1 mRNA的阳性神经元呈GFP阳性;(3)SNr内90%以上的GFP阳性神经元同时表达KCC2,双标神经元约占KCC2阳性神经元的50.5%;(4)SNr内80.5%以上的GFP阳性神经元同时表达NKCC1,双标神经元约占NKCC1阳性神经元的42.5%。以上结果表明,SNr内表达GFP的GABA能神经元大部分与KCC2和NKCC1共存,提示氯离子共转运体可能对SNr内GABA能神经元起重要的调控作用。     

重组腺相关病毒转导外源基因入EB病毒转化的B淋巴细胞获长期表达

目的 采用重组腺相关病毒（AAV）载体pAGX( ),把6A8α-甘露糖苷酶基因的正义或反义DNA片段转导入EB病毒转化的B淋巴细胞,以获得正义或反义6A8DNA长期表达的B淋巴细胞株。方法 构建含正义或反义6A8DNA片段的重组pAGX( )质粒,经包装后转导淋巴细胞,经G418筛选,用有限稀释法克隆转导成功的淋巴细胞。Northern杂交和RT-PCR检测转导基因的mRNA表达水平。ConA结合试验检测细胞在转导基因后6A8α-甘露糖苷酶活性的改变,结果 pAGX-反义6A8DNA及pAGX-正义6A8DNA经包装获得了高复制滴度的重组AAV（rAAV)颗粒,藉助rAAV成功地把6A8基因转导入EB病毒转化的B细胞株SKW6和B淋巴样白血病细胞株BJAB。Northern杂交结果显示,转导的正义或反义6A8DNA获得表达,经1年余传代培养,RT-PCR检测见BJAB和SKW6细胞中转导的正义或反义6A8DNA的mRNA表达增加,新霉素抗性基因（neo^R)也获得表达,表明转导基因获得了长期表达,ConA结合强度在转导反义6A8DNA的细胞升高,提示转导反义6A8DNA可影响6A8α-甘露糖苷酶的表达。结论 用AAV载体成功地把6A8α-甘露糖苷酶基因的正义或反义DNA片段转导入EB病毒转化的B淋巴细胞SKW6和B淋巴样白血病细胞株BJAB,转导的基因获得长期表达,并干扰6A8α-甘露糖苷酶的表达。     

腺病毒伴随病毒载体介导的Ⅰ型单纯疱前病毒胸苷 …

目的 研究腺病毒伴随病毒（ＡＡＶ）载体介导杀肿瘤瘤基因的转移及其在肿瘤治疗方面的应用。方法 应用作者构建的腺病毒伴随病毒载体，克隆Ⅰ型单纯疱疹病毒胸苷激酶（ＨＳＶＩ－ＴＫ）基因，构建质粒ｐＡＣＴＫ－１９。用ｐＡＣＴＫ－１９转染５型腺病毒（Ａｄ５）感染的重组ＡＡＶ包装细胞系ＡＥ１２０１，获得重组病毒ｒＡＡＶ／ＡＣＴＫ。再用此重组病毒感染肺癌细胞系Ａ５４９，并联合现氧鸟苷（ＧＣＶ）作用，研究其体外对肺     

通用型腺病毒伴随病毒载体的构建

目的构建含腺病毒伴随病毒（ＡＡＶ）基因组两端的反向重复序列（ＩＴＲｓ）和表达必须元件如启动子、多克隆位点和ＰｏｌｙＡ信号的通用型载体质粒ｐＡＣＲ－Ｎｅｏ，并获得重组ＡＡＶ（ｒＶＶ／ＡＣＲ－Ｎｅｏ）。方法通过ＤＮＡ重组技术，将ＳＶ４０ＰｏｌｙＡ、Ｎｅｏ基因、ＣＭＶ－ＩＥ启动子和多克隆位点组成表达盒子，取代含ＡＡＶ全基因组质粒ｐＳＳＶ９中ＡＡＶ结构基因部分，构建成质粒ｐＡＣＲ－Ｎｅｏ。用ｐＡＣＲ－Ｎｅｏ转染５型腺病毒（Ａｄ５）感染的重组ＡＡＶ包装细胞系ＡＥ１２０１，能获得重组病毒ｒＡＡＶ／ＡＣＲ－Ｎｅｏ。提取ｒＡＡＶ／ＡＣＲ－Ｎｅｏ感染细胞的染色体，用Ｓｏｕｔｈｅｍ杂交分析重组病毒基因组在感染细胞中的存在情况。结果质粒ｐＡＣＲ－Ｎｅｏ转染包装细胞系后所得ｒＡＡＶ／ＡＣＲ－Ｎｅｏ滴度为４．２×１０５ＣＦＵ／ｍｌ，并且ｒＡＡＶ／ＡＣＲ－Ｎｅｏ能在转导细胞内实现其基因组与细胞染色体的整合。结论成功地构建了通用型ＡＡＶ载体，为今后的ＡＡＶ载体研究、基因治疗和临床应用打下了基础     

Boosting anti-idiotype immune response with recombinant AAV enhances tumour protection induced by gene gun vaccination

Thanks to the safety of administration, efficiency of in vivo transduction and persistence of transgene expression, vectors based on the adeno-associated virus (AAV) are extensively utilized in both preclinical and clinical experimentation. Here we thoroughly explore the potential of AAV-mediated antigen delivery for tumour vaccination. A recombinant AAV vector (rAAV) encoding a lymphoma idiotype (Id) in a single-chain variable fragment format was found to induce an efficient anti-Id immune response upon injection in immunocompetent animals. The intensity of the immune response and the protective effect of rAAV administration in vivo were systematically compared with those elicited by simple injection of naked DNA or biolistic immunization. The results indicate that Id delivery via rAAV enhances the intensity of immune response compared with injection of naked DNA, while anti-idiotypic antibodies titres are not considerably increased compared with biolistic vaccination. On the contrary, a prime-boost vaccination strategy combining biolistic and AAV DNA delivery results in a major increase in anti-Id antibody response compared with the repetitive biolistic immunization. This increased anti-Id humoral response strictly correlated with a significant improvement on tumour protection in vivo .     

Adenosine A(2A) receptor-mediated modulation of GABA and glutamate release in the output regions of the basal ganglia in a rodent model of Parkinson's disease

A target neuron of adenosine A(2A) receptor antagonists to exert anti-parkinsonian activities has been currently identified to be, at least in part, striatopallidal medium spiny neurons (MSNs). In the present study, we determine whether A(2A) receptor-mediated modulation is associated with changes in the release of GABA and glutamate in the substantia nigra pars reticulata (SNr), an output structure of the whole basal ganglia network, using in vivo microdialysis in a rat Parkinson's disease (PD) model. In 6-hydroxydopamine (OHDA)-lesioned rats compared with normal rats, basal extracellular GABA levels in the SNr show no change, whereas basal glutamate levels are significantly increased. Oral administration of the A(2A) receptor-selective antagonist (E-1,3-diethyl-8-(3,4-dimethoxystyryl)-7-methyl-3,7-dihydro-1-H-purine-2,6-dion (KW-6002) to 6-OHDA-lesioned rats at 1 mg/kg caused a marked and sustained increase of GABA and glutamate levels in the SNr. The increase of nigral glutamate by KW-6002 was abolished by a kainic acid-induced lesion of the globus pallidus (GP) or subthalamic nucleus (STN) in 6-OHDA-lesioned rats, whereas the increase of nigral GABA was completely blocked by the GP-lesion but only partially blocked by the STN-lesion. These results indicate that changes in neurotransmitter release in the SNr brought about by KW-6002 are largely attributable to blockade of A(2A) receptor-mediated modulation of striatopallidal MSNs. Thus, these actions of KW-6002 on striatopallidal MSNs may be the main mechanism for ameliorating PD by A(2A) antagonists.     

重组病毒rAAV2-IRES-EGFP/MnSOD的构建及其表达

目的构建含有大鼠源性锰超氧化物歧化酶(MnSOD)基因的重组病毒rAAV2-IRES-EGFP/Mn-SOD,检测其在大鼠耳血管纹边缘细胞和耳蜗组织内的表达。方法将大鼠心肌组织来源的SOD基因克隆入融合表达载体pEGFP-N1中,再以限制性酶切方法克隆入真核表达载体pSNAV2.0-IRES-EGFP中,最后将其包装为rAAV2-IRES-EGFP/MnSOD病毒颗粒,用激光共聚焦显微镜、流式细胞仪、RT-PCR及Western印迹检测MnSOD基因的表达。结果真核表达载体pEGFP-N1/MnSOD和pSNAV2.0-IRES-EGFP/MnSOD经酶切、PCR和测序鉴定均检测到MnSOD基因的完整序列,被rAAV2-EGFP/MnSOD感染的耳边缘细胞和内耳组织中MnSOD蛋白的表达均高于空白对照耳。结论成功构建了大鼠源性MnSOD基因的重组病毒rAAV2-IRES-EGFP/MnSOD,并使其在大鼠耳边缘细胞和大鼠耳蜗组织中成功表达,为抗氧化基因治疗内耳疾病的研究奠定了基础。     

Optimization of recombinant adeno-associated virus production using an herpes simplex virus amplicon system.

A major limitation of adeno-associated virus (AAV) based vectors for clinical applications to date is the production of high-titer recombinant AAV vector stocks. Despite recent improvements, the amount of recombinant adeno-associated virus vectors (rAAV) particles produced per cell continues to be significantly lower than that of wild-type AAV. In this study, an HSV-based system for rAAV production was used to examine the influence of different parameters including transfection conditions (vector-to-packaging plasmid ratio, amount of total transfected DNA, cell confluency) and multiplicity of infection of herpes helper virus on the resulting titre of rAAV stocks. For herpes helper virus, time-course experiments were carried out to analyse the effect on rAAV yields up to 72 h postinfection and to determine the ideal harvesting time. Taken together, the optimized production scheme consistently yields more than 3x10(3) transducing units per producer cell.     

腺相关病毒介导胰岛素样生长因子Ⅰ对高糖诱导神经元凋亡的保护作用

目的 研究重组腺相关病毒(AAV)载体介导胰岛素样生长因子Ⅰ(IGF Ⅰ)在体外神经元表达的情况,及其对高糖诱导神经元凋亡的保护作用.方法 利用分子克隆技术将大鼠IGF Ⅰ基因克隆到pSNAV2.0质粒上,构建包含重组质粒pSNAV2.0-IGF Ⅰ的杂合型重组AAV载体rAAV2/1-IGF Ⅰ.将人神经母细胞瘤SH-SY5Y细胞分为正常组(A组)、无血清组(B组)、无血清高糖组(C组),无血清高糖+rAAV2/1-IGF Ⅰ组(D组),其中A组不做任何处理;B组使用无血清培养基培养;C组用含100mmol/L D-葡萄糖的无血清培养基培养;D组则先用rAAV2/1-IGF Ⅰ病毒载体感染后再用含100 mmol/LD-葡萄糖的无血清培养基处理.干预24 h后应用RT-PCR和Western免疫印迹检测各组IGF Ⅰ基因和蛋白的表达情况;应用Hoechst33342荧光染色法、AnnexinV-FITC/PI双染法流式细胞仪检测细胞凋亡.观察rAAV2/1-IGF Ⅰ感染后对高糖诱导SH-SY5Y细胞凋亡的保护作用.结果 成功构建rAAV2/1-IGF Ⅰ重组AAV载体.感染SH-SY5Y细胞后,RT-PCR显示SH-SY5Y能表达大鼠IGF Ⅰ基因;Western免疫印迹检测发现D组IGF Ⅰ蛋白的表达水平(0.44±0.04)显著高于其他3组(A组0.29±0.02,B组0.17+0.02,C组0.08±0.02,均P<0.05).rAAV2/1-IGF Ⅰ能明显降低高糖诱导细胞捌亡的凋亡率:Hoechst33342荧光染色检测总凋亡率分别为A组(2.71±1.03)%,B组(9.17±1.72)%,C组(25.63±1.81)%,D组(14.50±2.27)%,各组间差异均有统计学意义(P<0.05);流式细胞仪分析结果表明AnnexinV-FITC~+/PI~+的早期凋亡细胞加上AnnexinV-FITC~+/PI~+的晚期凋亡细胞的总细胞凋亡率A组为(5.01±1.17)%,B组为(9.87±1.38)%,C组为(27.56±2.25)%,D组为(17.34±2.08)%,各组间差异均有统计学意义(P<0.05).结论 rAAV2/1-IGF Ⅰ感染体外神经元SH-SY5Y细胞能显著表达IGF Ⅰ蛋白,并有效地降低高糖对神经元的诱导凋亡作用.     

反义细胞周期蛋白B1重组AAV抑制骨肉瘤U2OS细胞增殖和诱导凋亡

目的 研究携带反义细胞周期蛋白B1(CCNB1)的腺相关病毒载体(rAAV-AS-CCNB1/Neo)对骨肉瘤细胞U2OS的细胞增殖抑制和诱导凋亡的影响. 方法 将构建的重组AAV载体pd16-95-AS-CCNB1/neo和AAV/腺病毒辅助质粒pSH3共转染HEK293细胞,得到表达AS-CCNB1的重组AAV,纯化并浓缩病毒,测定病毒滴度.用重组AAV感染人骨肉瘤U2OS细胞(感染复数为105～106 v.g./细胞),采用Western blotting、RT-PCR、四甲基偶氮唑盐(MTT)法、流式细胞术等检测或观察重组AAV对细胞周期蛋白B1表达,瘤细胞体外增殖、凋亡和细胞周期的影响.结果 成功构建rAAV-AS-CCNB1,病毒滴度为1.0×1011 v.g./ml,体外感染U2OS细胞后可明显降低其增殖活性,Western blotting和RT-PCR提示,rAAV-AS-CCNB1可抑制细胞周期蛋白B1表达,流式细胞术提示,细胞出现明显凋亡和G1期阻滞. 结论 反义CCNB1重组AAV具有明显的抗骨肉瘤U2OS细胞体外增殖作用,其作用可能与其诱导细胞凋亡和周期阻滞有关.     

Evaluation of risks related to the use of adeno-associated virus-based vectors

Recombinant AAV efficacy has been demonstrated in numerous gene therapy preclinical studies. As this vector is increasingly applied to human clinical trials, it is a priority to evaluate the risks of its use for workers involved in research and clinical trials as well as for the patients and their descendants. At high multiplicity of infection, wild-type AAV integrates into human chromosome 19 in approximately 60% of latently infected cell lines. However, it has been recently demonstrated that only approximately 1 out of 1000 infectious units can integrate. The mechanism of this site-specific integration involves AAV Rep proteins which are absent in vectors. Accordingly, recombinant AAV (rAAV) do not integrate site-specifically. Random integration of vector sequences has been demonstrated in established cell lines but only in some cases and at low frequency in primary cultures and in vivo. In contrast, episomal concatemers predominate.Therefore, the risks of insertional mutagenesis and activation of oncogenes are considered low. Biodistribution studies in non-human primates after intramuscular, intrabronchial, hepatic artery and subretinal administration showed low and transient levels of vector DNA in body fluids and distal organs. Analysis of patients body fluids revealed rAAV sequences in urine, saliva and serum at short-term. Transient shedding into the semen has been observed after delivery to the hepatic artery. However, motile germ cells seemed refractory to rAAV infection even when directly exposed to the viral particles, suggesting that the risk of insertion of new genetic material into the germ line is absent or extremely low. Risks related to viral capsid-induced inflammation also seem to be absent since immune response is restricted to generation of antibodies. In contrast, transgene products can elicit both cellular and humoral immune responses, depending on the nature of the expressed protein and of the route of vector administration. Finally, a correlation between early abortion as well as male infertility and the presence of wt AAV DNA in the genital tract has been suggested. Although no causal relationship has been established, this issue stresses the importance of using rAAV stocks devoid of contaminating replication-competent AAV. This review comprehensively examines virus integration, biodistribution, immune interactions, and other safety concerns regarding the wild-type AAV and recombinant AAV vectors.