犬白细胞介素-7基因对犬细小病毒DNA疫苗的免疫增强作用

【目的】白介素-7是动物体一种重要的多功能细胞因子,在促进B细胞、T细胞的形成和发育,在协同其它细胞因子提高机体免疫能力等方面发挥重要作用。本试验利用犬细小病毒VP2 DNA疫苗,在小鼠体内分析了犬白介素-7（cIL-7）基因的免疫增强作用。【方法】采用RT-PCR方法从犬脾淋巴细胞中扩增cIL-7基因,然后将cIL-7基因插入到真核表达载体pcDNA3.1A中,分别构建成与Myc/His标签融合和非融合的cIL-7真核分泌型表达载体pcDNA-cIL7/MH和pcDNA-cIL7。由磷酸钙介导将pcDNA-cIL7/MH质粒转染HEK 293T细胞使其进行瞬时表达,以Western-blot检测构建的表达载体能否介导cIL-7基因在真核细胞中进行分泌表达。用已构建的VP2表达载体pcDNA-CD5-VP2与pcDNA-cIL7载体共免疫小鼠,并设pcDNA-CD5-VP2单免疫小鼠和pcDNA-cIL7单免疫小鼠作为对照。免疫后通过ELISA方法检测抗体水平,并通过淋巴细胞增殖实验和ELISA方法分别检测免疫后35 d小鼠脾脏淋巴细胞刺激指数和γ-干扰素的表达水平。【结果】本试验扩增的cIL-7基因序列与GenBank中犬的序列完全一致。构建的表达载体能够介导cIL-7基因在HEK293T细胞中进行分泌表达。动物免疫试验结果显示,cIL-7与VP2共免疫组小鼠血清的抗体滴度和中和抗体效价分别极显著和显著高于VP2单免疫组（P＜0.01和P＜0.05）;共免疫组小鼠淋巴细胞刺激指数和γ-干扰素表达水平也显著高于VP2单免疫组（P＜0.05）。【结论】cIL-7基因可增强小鼠对VP2 DNA疫苗的免疫应答反应。     

多聚赖氨酸-硅纳米的制备及体外转染HepG2细胞的研究

目的观察多聚赖氨酸-硅纳米颗粒作为基因转染载体体外转染肝癌细胞系HepG2细胞的可行性。方法自制硅纳米颗粒并用多聚赖氨酸修饰,与增强型绿色荧光蛋白基因质粒(pEGFP-C1)结合后体外转染HepG2细胞,观察转染后绿色荧光蛋白表达情况,计算转染效率。结果制备出大小均匀、粒径30 nm、稳定性及分散性好的球形硅纳米,硅纳米表面经多聚赖氨酸修饰后作为基因转染载体,能有效地转染pEGFP-C1进入HepG2细胞,转染效率为30%~40%。结论本文成功制备了多聚赖氨酸-硅纳米,该纳米颗粒在体外可作为基因载体,有效转染质粒pEGFP-C1。     

环氧合酶-2的DNA疫苗构建及其在COS-7细胞中表＊达

构建了环氧合酶-2（Cyclooxygenase-2,COX-2）的DNA疫苗载体pVAX1-COX-2,并考察在COS-7细胞中表达.用RT-PCR法从肺癌A549细胞中获得环氧合酶-2基因片段,此片段插入pVAX1载体构建pVAX1-COX-2真核重组表达质粒,脂质体介导法转染COS-7细胞,以pVAX1为对照,收集稳定转染细胞,利用RT-PCR和West-ern-blot分别在mRNA和蛋白水平上考察COX-2表达.实验结果表明：RT-PCR法从A549细胞mRNA中扩增1.8 kb的COX-2基因片段,酶切与测序结果表明所构建的真核表达载体pVAX1-COX-2与预期相符,质脂体法成功地将质粒DNA转染到COS-7细胞中.RT-PCR和Western-blot分析结果表明COX-2已表达.因此,所构建的真核表达载体pVAX1-COX-2正确,且在COS-7细胞中表达.     

猪瘟病毒E2基因真核表达载体表达效率和免疫效果的比较

比较猪瘟病毒E2基因的真核表达质粒proVAX-E2n和pVP22-E2n体外表达效率以及体内的免疫效果,以从中选出高效的猪瘟病毒核酸疫苗.将上述表达载体转染Hela细胞进行体外表达后,用RT-PCR和间接ELISA法检测Hela细胞体内和体外表达产物;免疫6～8周龄昆明白小鼠, 用间接ELISA法和MTS法检测小鼠血清中CSFV特异性IgG抗体水平以及脾脏中淋巴细胞增殖功能.结果表明2种E2重组质粒均能在Hela细胞中正确表达,且proVAX-E2n的E2蛋白表达量（OD值为0.575 4）明显高于pVP22-E2n（OD值为0.306 05）（P〈0.05）;proVAX-E2n刺激机体产生的抗体水平（最高抗体滴度为1：2 200）显著高于pVP22-E2n免疫组（最高抗体滴度1：1 600）;淋巴细胞增殖结果显示proVAX-E2n（刺激指数4.073）与pVP22-E2n（刺激指数2.205）相比,能诱发小鼠产生更强的CSFV的特异性淋巴细胞增殖反应.本研究表明proVAX真核表达载体对E2基因体外表达效率和小鼠免疫效果均高于pVP22真核表达载体.     

IL-18基因转染对大鼠胶质瘤体内生长及肿瘤细胞凋亡的影响

目的分析转染外源性IL-18基因后9L胶质瘤细胞体内成瘤及对肿瘤细胞凋亡的影响。方法用立体定向技术将体外用逆转录病毒转染IL-18基因的9L胶质瘤细胞(9L/IL-18)、转染空载体的9L胶质瘤细胞(9L/LXSN)及未转染的9L细胞接种到F344大鼠颅内建立实验动物模型,观察各组细胞对大鼠的致瘤性,计算成瘤率;原位末端标记法(TUNEL法)检测肿瘤组织中肿瘤细胞凋亡情况,计算各组肿瘤细胞的凋亡率;RT-PCR和Westen Blot法检测肿瘤组织中Bax和Bcl-2的表达。结果三组大鼠成瘤率均为100%;TUNEL法检测结果显示,接种9L/IL-18细胞组肿瘤组织内出现大量凋亡细胞,凋亡率为(22.2±1.02)%,明显高于接种9L/LXSN[(5.7±0.32)%]及9L[(6.4±0.51)%]细胞组(P0.05);接种9L/IL-18细胞组肿瘤组织中Bax的表达较其他两组升高,Bcl-2的表达较其他两组降低。结论 9L胶质瘤细胞转染外源性IL-18基因后,可通过上调Bax的表达,下调Bcl-2的表达促进肿瘤细胞凋亡,发挥抗肿瘤作用。     

IL-15基因对犬细小病毒VP2 DNA疫苗的免疫增强作用

为弄清犬白介素-15(cIL-15)能否增强犬细小病毒VP2DNA疫苗的免疫原性,本研究首先通过RT-PCR方法从犬脾脏淋巴细胞中扩增全长cIL-15cDNA基因,并构建其与Myc-His-tag融合和非融合的表达载体:pcDNA-cIL-15/MH和pcDNA-cIL-15。将pcDNA-cIL-15/MH载体转染HEK293T细胞,确定构建的表达载体能否介导cIL-15进行分泌表达。利用过去构建的VP2表达载体和pcDNA-cIL-15载体共免疫小鼠,用ELISA检测免疫后小鼠血清中的抗体滴度,并用MTT检测小鼠淋巴细胞的增殖活性和用ELISA测定淋巴细胞干扰素-γ和IL-4的表达。结果显示,构建的cIL-15表达载体能够介导cIL-15在真核细胞中的分泌表达。用VP2和cIL-15表达载体共免疫小鼠,抗体水平明显高于VP2载体单免疫组(P0.01)。当免疫35d时,共免疫组淋巴细胞的刺激指数、干扰素-γ和IL-4的表达水平均明显高于VP2载体单免疫组(P0.05)。结果表明,cIL-15可明显增强VP2DNA疫苗的免疫原性。     

siRNA抑制口蹄疫病毒在BHK-21细胞中复制的研究

选取口蹄疫病毒(FMDV)的VP1、IRES、2B、3D和L基因保守序列,设计、合成siRNA,并成功构建表达siRNA的穿梭载体,通过脂质体2000在BHK-21细胞上转染6个重组siRNA表达质粒,观察其对FMDV S72毒株复制的抑制效果.结果发现:病毒对照和空载体对照细胞死亡脱落,脂质体2000对照和细胞对照细胞状态良好; 6个siRNA转染孔细胞状态明显优于病毒对照孔,表明6个重组质粒转染后均可以显著抑制FMDV S72毒株的复制,其中靶向IRES1基因的siRNA对FMDV的复制抑制最为明显.     

PC12细胞诱导的神经缺血细胞Smad7-siRNA及沉默效果的检测

目的探讨诱导PC12细胞分化的神经细胞靶向沉默Smad7基因特性,同时进行沉默效果检测．方法以Smad7基因为靶目标,设计合成3条siRNA序列,进行细胞转染,利用Rea1time—PCR和Westernblot技术检测沉默效果,筛选出最有效的干扰序列,同时检测出最佳的转染浓度和转染时间．结果针对Smad7基因设计合成及筛选出靶向沉默Smad7基因的干扰序列（siRNA1）;siRNA1的最佳转染浓度是4μg／mL;siRNA1的最佳转染时间是24h;siRNA1对Smad7的抑制效果优于其他干扰序列．结论siRNA1能有效沉默Smad7基因;lipofecta—mineTM2000可成功将siRNA1转染至神经细胞,转染效率较高;利用siRNA技术能有效抑制神经细胞．     

环氧合酶-2的DNA疫苗构建及其在COS-7细胞中表达

构建了环氧合酶-2(Cyclooxygenase-2, COX-2)的DNA疫苗载体pVAX1-COX-2, 并考察在COS-7细胞中表达. 用RT-PCR法从肺癌A549细胞中获得环氧合酶-2基因片段, 此片段插入pVAX1载体构建pVAX1-COX-2真核重组表达质粒, 脂质体介导法转染COS-7细胞, 以pVAX1为对照, 收集稳定转染细胞, 利用RT-PCR和Western-blot分别在mRNA和蛋白水平上考察COX-2表达. 实验结果表明: RT-PCR法从A549细胞mRNA中扩增1.8 kb的COX-2基因片段, 酶切与测序结果表明所构建的真核表达载体pVAX1-COX-2与预期相符, 质脂体法成功地将质粒DNA转染到COS-7细胞中. RT-PCR和Western-blot分析结果表明COX-2已表达. 因此, 所构建的真核表达载体pVAX1-COX-2正确, 且在COS-7细胞中表达.     

Let-7a负性调控人肾上皮细胞293T中UHRF1基因的表达

目的:探讨人肾上皮细胞293T中let-7a对靶基因UHRF1的负性调控作用.方法:运用生物信息学技术对let-7a靶基因进行预测和分析.构建含有UHRF1 3'UTR全长的野生型(pmiR-RB-UHRF1-3'UTR-wt)和突变型荧光素酶报告质粒(pmiR-RB-UHRF1-3'UTR-mut),分别将pmiR-RB-UHRF1-3'UTR-wt,pmiR-RB-UHRF1-3'UTRmut,pmiR-RB-REPORT vector与let-7amimics或mimics control共转染293T细胞,双荧光素酶报告系统检测转染后293T细胞的荧光素酶表达水平.293T细胞分别转染let-7amimics和inhibitor,western blot和real-time RT PCR检测UHRF1基因的表达.结果:生物信息学结果显示let-7a有48个预测靶基因,包括UHRF1,HMGA2,MAPK6等,主要涉及microRNA在肿瘤、细胞周期、PI3K-AKT、p53等信号通路.其中UHRF1 3'UTR含有一个let-7a的结合位点,且在多个物种中呈高度保守.进一步双荧光素酶检测发现,共转染let-7amimics和pmiR-RBUHRF1-3'UTR-wt的293T细胞荧光素酶活性显著降低(p0.01).Western blot和real-time RT PCR结果显示转染let-7amimics的293T细胞UHRF1表达降低,而转染let-7ainhibitor的293T细胞UHRF1表达增高.结论:人肾上皮细胞293T中let-7a能通过与UHRF13'UTR靶向结合,负性调控UHRF1的表达.     

Lipofectin介导bcl-xL反义寡核苷酸对鼻咽癌CNE-2Z细胞的影响

目的：探讨阳离子脂质体Lipofectin对bcl-xL反义寡核苷酸进入CNE－2Z细胞的影响。方法：采用阳离子脂质体Lipofectin介导bcl-xL反义寡核苷酸转染CNE－2Z细胞，应用MTT法观察Lipofectin介导前后对CNE－2Z增殖的影响；RT－PCR检测处理前后bcl-xL mRNA表达水平。结果：Lipofectin介导bcl-xl反义核酸可提高反义核酸对细胞的增殖抑制率；Lipofectin介导bcl-xL反义核酸可增强反义核酸下调bcl-xL mRNA表达水平的能力。结论：Lipofectin可促进反义核酸转染进入细胞。     

转染抑癌基因PTEN对人乳腺癌ZR-75-1细胞的细胞周期和增殖能力的影响

目的：观察PTEN（phosphatase and tensin homology deleted on chromosome ten，第10号染色体上磷酸酶和张力蛋白同源缺失的基因）对人乳腺癌细胞ZR-75-1细胞增殖和细胞周期的影响。方法；利用脂质体介导法将携带有野生型和突变型PTEN cDNA的真核表达载体pBP—wt—PTEN和pBP—G129R—PTEN导八人乳腺癌ZR-75-1细胞（质粒转染成功后实验分为C—WT—PTEN组、CG129R—PTEN组和未转染质粒组即对照组）后，以RT—PCR、Western blot分析目的基因的表达，并采用MTT法和流式细胞术检测细胞增殖和细胞周期。结果：C—WT—PTEN组、C—G129R—PTEN组细胞PTEN mRNA及PTEN蛋白出现明显的高表达。C—WT—PTEN组细胞生长的抑制率可高达42．7％，与对照组比较．差异有显著性（P〈0．05）。但C—G129R—PTEN组细胞生长的抑制率与对照组比较，差异无显著性（P〉0．05）。流式细胞术显示C—WT—PTEN组细胞周期从G1期到S期已发生抑制。结论：野生型PTEN可依赖其磷酸酶活性抑制肿瘤细胞的增殖,并最终诱导细胞凋亡。     

Oncogene-induced transformation of C3H 10T1/2 cells is enhanced by tumor promoters

The tumor promoters 12-O-tetradecanoyl-phorbol-13-acetate and teleocidin markedly enhanced the transformation of C3H 10T1/2 mouse fibroblasts when these cells were transfected with the cloned human bladder cancer c-rasH oncogene. Transfection studies with the drug resistance marker gpt and time course studies indicate that this enhancement is not simply an effect on the process of DNA transfection. These findings, together with parallel studies with NIH 3T3 fibroblasts, also indicate that the competence of animal cells for DNA transfection is a function of the recipient cell line, the transfected marker, and the growth conditions. Our findings suggest that during multistage carcinogenesis tumor promoters may complement the function of activated cellular oncogenes.     

重组质粒pDsRed1-C1-PinX1的建立及其在乳腺癌MCF-7细胞中的表达

目的构建PinX1真核表达载体,观察PinX1基因对乳腺癌MCF-7细胞生长和增殖的影响。方法重组质粒转染MCF-7细胞并筛选稳定表达系;用Real-timePCR检测PinX1基因mRNA的表达;MTT法检测转染前后细胞生长变化;平板克隆形成试验检测PinX1对MCF-7集落形成能力的影响。结果构建了真核表达载体PDsRed1-C1-PinX1的稳定表达系;转染后乳腺癌MCF-7细胞生长明显减缓,集落形成能力降低。结论 PinX1基因可抑制乳腺癌MCF-7细胞的生长和增殖。     

Recombinant human granulocyte colony-stimulating factor: effects on normal and leukemic myeloid cells

Experiments were conducted to isolate and characterize the gene and gene product of a human hematopoietic colony-stimulating factor with pluripotent biological activities. This factor has the ability to induce differentiation of a murine myelomonocytic leukemia cell line WEHI-3B(D+) and cells from patients with newly diagnosed acute nonlymphocytic leukemia (ANLL). A complementary DNA copy of the gene encoding a pluripotent human granulocyte colony-stimulating factor (hG-CSF) was cloned and expressed in Escherichia coli. The recombinant form of hG-CSF is capable of supporting neutrophil proliferation in a CFU-GM assay. In addition, recombinant hG-CSF can support early erythroid colonies and mixed colony formation. Competitive binding studies done with 125I-labeled hG-CSF and cell samples from two patients with newly diagnosed human leukemias as well as WEHI-3B(D+) cells showed that one of the human leukemias (ANLL, classified as M4) and the WEHI-3B(D+) cells have receptors for hG-CSF. Furthermore, the murine WEHI-3B(D+) cells and human leukemic cells classified as M2, M3, and M4 were induced by recombinant hG-CSF to undergo terminal differentiation to macrophages and granulocytes. The secreted form of the protein produced by the bladder carcinoma cell line 5637 was found to be O-glycosylated and to have a molecular weight of 19,600.     

Monoclonal antibody-mediated tumor regression by induction of apoptosis

To characterize cell surface molecules involved in control of growth of malignant lymphocytes, monoclonal antibodies were raised against the human B lymphoblast cell line SKW6.4. One monoclonal antibody, anti-APO-1, reacted with a 52-kilodalton antigen (APO-1) on a set of activated human lymphocytes, on malignant human lymphocyte lines, and on some patient-derived leukemic cells. Nanogram quantities of anti-APO-1 completely blocked proliferation of cells bearing APO-1 in vitro in a manner characteristic of a process called programmed cell death or apoptosis. Cell death was preceded by changes in cell morphology and fragmentation of DNA. This process was distinct from antibody- and complement-dependent cell lysis and was mediated by the antibody alone. A single intravenous injection of anti-APO-1 into nu/nu mice carrying a xenotransplant of a human B cell tumor induced regression of this tumor within a few days. Histological thin sections of the regressing tumor showed that anti-APO-1 was able to induce apoptosis in vivo. Thus, induction of apoptosis as a consequence of a signal mediated through cell surface molecules like APO-1 may be a useful therapeutic approach in treatment of malignancy.     

基于Smad 7基因为靶序列的RNA干涉作用研究

为了探讨小干涉RNA(siRNA)对靶基因Smad7mRNA表达的阻断作用,采用体外转录方法制备Smad7基因的小干涉RNAs(siRNAs),用脂质体介导瞬时转染BERP35T 2肺癌细胞系,并采用Northernblot杂交检测靶基因mRNA的表达丰度。结果表明,根据Smad7编码区序列在体外成功地制备了针对2个不同靶序列的siRNAs;Northernblot杂交显示,在转染siRNA的BERP35T 2细胞中,不管是内源性的还是外源性的,Smad7mRNA的表达丰度均明显下降。说明Smad7基因编码区中542563bp及701722bp2个区域均是siRNA作用的有效靶序列,本研究设计并制备的siRNAs能有效抑制Smad7基因的表达。     

Knockdown of the Meq gene in Marek's disease tumor cell line MSB1 might induce cell apoptosis and inhibit cell proliferation and invasion

Marek's disease (MD), a highly cell-associated and contagious disease of chickens caused by Marek's disease virus (MDV) can result in neural lesions, immunosuppression and neoplasia in chicken. The Meq gene is an important oncogene in the MDV genome, and it is expressed highly in MD tumor tissues and MD T-lymphoblastoid cell lines. An experiment was conducted to elucidate the role of Meq in MD tumor transformation. RNA interference technology was used to block its expression, and then analyzed the biological effects of Meq knockdown on the MD tumor cell line MSB1. A small interfering RNA with an interference efficiency of 70% (P<0.01) was transfected into MSB1 cells to knock down the expression of Meq gene. The cell proliferation, cycle and apoptosis were detected post-Meq knockdown. The results showed that MSB1 cell proliferation was downregulated remarkably at 48 h (P<0.01), 60 h (P<0.05) and 72 h (P<0.01) post-Meq knockdown. The cell cycle was unaffected (P>0.05). B-cell lymphoma 2 gene (BCL2) was anti-apoptotic and caspase-6 was the effector in the apoptosis pathway. The activity of caspase-6 was upregulated (P<0.05) significantly and BCL2 gene expression was downregulated (P<0.05) significantly post-Meq knockdown, suggesting cell apoptosis might be induced. MSB1 cell migration did not exhibit any obvious change (P>0.05) post-Meq knockdown, but the expression of two genes (matrix metalloproteinase 2 (MMP2) and MMP9) that are correlated closely to cell invasion was downregulated (P<0.05) remarkably post-Meq knockdown. The Meq knockdown might affect the main features of tumorous cells, including proliferation, apoptosis, and invasion, suggesting that the Meq gene might play a crucial role in interfering with lymphomatous cell transformation.     

Effect of MSTN Propeptide and shRNA Co-expression Vector on Proliferation of Skeletal Muscle Satellite Cells

Myostatin(MSTN)is a negative regulator of skeletal muscle growth,in order to study the effect of inhibition MSTN expression on the proliferation of bovine skeletal muscle satellite cells,we constructed co-expression vector pcDNA3.1-ProMSTNshRNA,transfected it into muscle satellite cells by Liposome 2000,and detected cell proliferation changes by CCK-8 method and flow cytometry after 48 h.The expressions of P21 and CDK2 were detected by Western blot and real-time PCR.The results showed that the cell vitality of experimental groups significantly increased than that of the negative control,and cells in S phase also increased significantly(P<0.05).After knocked down MSTN gene,P21 expression decreased(P<0.05),but CDK2 gene expression increased(P<0.05).These results indicated that MSTN gene expression was associated with P21 and CDK2,the proliferation of skeletal muscle satellite cells could be promoted while MSTN was inhibited,which provided a theoretical basis for the study on transgenic cattle.     

牛分枝杆菌ag85b基因的瞬时表达

[目的]为牛结核病DNA疫苗的研制提供参考。[方法]利用PCR技术扩增出牛分枝杆菌ag85b基因片段,克隆到真核载体pcD-NA3.1(+)上,构建重组质粒pcAg85B,将重组质粒转染SP2/0细胞,间接免疫荧光试验检测该基因的表达情况。[结果]结果表明:在转染了重组质粒pcAg85B的SP2/0细胞中出现绿色荧光,说明ag85b基因在SP2/0细胞中成功进行了瞬时表达。[结论]为研究牛分枝杆菌ag85b DNA疫苗奠定了基础。