阴离子脂质体－阳离子脂质体复合物介导的基因转染

目的评价阴离子脂质体-阳离子脂质体复合物介导质粒转移至HepG2肝癌细胞中及其毒副作用。方法制备携载表达绿色荧光蛋白质粒的阳离子脂质体,与阴离子脂质体形成复合物。测定脂质体复合物的zeta电位,凝胶阻滞实验考察质粒包封情况,流式细胞仪测量各阴离子脂质体-阳离子脂质体复合物的转染效率,MTT法检测细胞毒性。结果复合物能完全包裹质粒,其zeta电位低于阳离子脂质体zeta电位;脂质体复合物介导的转染效率略低于阳离子脂质体,其细胞生存率高于阳离子脂质体。结论阴离子脂质体-阳离子脂质体复合物在降低细胞毒性的同时,可实现对HepG2细胞较高的转染效率。     

双特异性抗体在恶性肿瘤临床治疗中的研究进展

肿瘤免疫治疗包括免疫检查点抑制剂、单克隆抗体疗法、过继细胞疗法、溶瘤病毒疗法和肿瘤疫苗等。其机制为免疫治疗可激活体内T细胞识别肿瘤细胞的特异性抗原,诱发免疫细胞激活、克隆性增殖/扩增和靶细胞溶解反应,发挥杀伤肿瘤效应。相比于单克隆抗体,双特异性单克隆抗体可以通过靶向多个抗原或抗原表位发挥协同抗肿瘤作用,介导多种特定生物学效应,后者包括连接免疫细胞与肿瘤细胞,募集并激活免疫细胞来消灭肿瘤细胞;作用于多个信号通路,协调肿瘤杀灭生物过程;通过抗体双价结构来介导蛋白复合物形成。目前双特性抗体用于治疗晚期肺癌,乳腺癌,胃癌,结直肠癌和CD20阳性淋巴瘤等。本文就双特异性抗体在肿瘤临床治疗中的研究进展和应用综述。     

跨膜型超抗原金黄色葡萄球菌肠毒素A融合蛋白的抗肿瘤作用

目的　为扩大超抗原金黄色葡萄球菌肠毒素A(SEA)的抗瘤谱 ,制备跨膜型SEA融合蛋白 ,研究该蛋白制备的肿瘤疫苗的抗肿瘤作用。方法　在荷B16黑色素瘤的C5 7BL/ 6小鼠上 ,观察跨膜型SEA融合蛋白制备的肿瘤疫苗对荷瘤小鼠的免疫治疗作用和免疫保护作用 ,并通过乳酸脱氢酶 (LDH)释放法检测治疗组和免疫组小鼠脾细胞的天然杀伤细胞(NK)和细胞毒性T细胞 (CTL)活性。结果　融合蛋白制备的肿瘤疫苗能够显著抑制荷瘤小鼠肿瘤的生长 ,并延长其生存期 ,其脾细胞的NK和CTL活性显著增强。同时 ,该肿瘤疫苗对同种肿瘤细胞攻击可产生较强的免疫保护作用。结论　跨膜型SEA融合蛋白制备的肿瘤疫苗具有显著的抗肿瘤作用 ,可有效激发荷瘤小鼠机体的特异性和非特异性抗肿瘤免疫应答 ,增强CTL和NK活性。     

人鼠嵌合抗肿瘤细胞核单抗-空间稳定脂质体的制备及其体外靶向

目的研究人鼠嵌合抗肿瘤细胞核单抗(chTNT-3)-空间稳定脂质体的制备方法、免疫活性及体外靶向性。方法合成聚乙二醇末端带吡啶二硫丙酰基的磷脂衍生物(PDP-PEG-HSPE)，制备含PDP-PEG-HSPE的空间稳定脂质体，经二巯基苏糖醇还原后共价连接马来酰亚胺衍生化抗体。荧光胺法和钼蓝法测定脂质体与抗体的连接效率及抗体密度，激光散射粒度仪测定其粒径分布，ELISA法检测脂质体表面的抗体免疫活性。体外实验考察该免疫脂质体与固定Raji细胞的结合活性。结果chTNT-3-空间稳定脂质体的粒径分布为(115±33) nm。当初始Ab/PDP-PEG-HSPE=1∶10时，脂质体与抗体的连接效率为71%，抗体密度为106 μg Ab/μmol PL。chTNT-3经化学修饰后连接到脂质体表面，其免疫活性基本保留。chTNT-3-空间稳定脂质体能特异性地结合固定Raji细胞。结论通过PDP-PEG-HSPE法共价连接抗体制备的chTNT-3-空间稳定脂质体能基本保留chTNT-3的免疫活性，具有体外靶向细胞核抗原的能力。     

胆固醇衍生物阳离子脂质体复合EGFP—IL-1Ra质粒体外转染HELA细胞系的研究

目的研究胆固醇衍生物阳离子脂质体复合EGFP—IL—IRa质粒体外转染HELA细胞系的效率,为类风湿性关节炎治疗提供新的选择。方法制备新型胆固醇衍生物脂质体及EGFP—IL-1Ra质粒,两者结合转染HELA细胞系,通过体外凝胶阻滞试验检测阳离子脂质体与质粒DNA的最佳配比关系,MTT法检测脂质体细胞毒性,荧光免疫法检测HELA细胞的转染效率。结果实验中所用脂质体的IC50为650μg／mL,较对照组有更低的细胞毒性。脂质体／DNA质量比为50：1作为最适比例,荧光显微镜观测脂质体结合EGFP—IL-1Ra质粒转染HELA荧光强度高于单纯EGFP—IL-1Ra质粒转染组。结论胆固醇衍生物阳离子脂质体复合EGFP—IL-1Ra质粒可高效的转染HELA细胞系,有望成为类风湿性关节炎治疗的新方法。     

文摘

西班牙巴伦西亚大学医学院Moret—Tatay等用脂质体DOTAP将粒细胞巨噬细胞集落刺激因子（GM—CSF）基因修饰的pcDNA3和空pcDNA3质粒转染鼠源黑素瘤细胞B16，收获的转染细胞经放射线照射后-150℃冻存。冻存细胞融化后用分子探针Calcein-AM检测B16转染细胞的活性；ELISA检测转染细胞GM—CSF分泌。用转染的B16一GM—CSF细胞、B16-pcDNA3细胞、B16细胞和空白对照免疫小鼠。免疫小鼠尾静脉采血检测血清特异性抗鼠肿瘤膜蛋白（TMP）IgG和亚类。     

淋球菌NspA核酸疫苗小鼠体内诱生保护性抗体研究

目的进一步研究前期构建淋球菌NspA真核细胞表达质粒pcNspA作为淋病核酸疫苗的可行性。方法将pcNspA分别通过肌内注射(IM)、滴鼻(IN)和阴道接种(IVAG)等3种途径免疫BALB/c小鼠,对免疫鼠的血清、支气管肺泡和阴道洗液等样品分别用间接ELISA检测淋球菌特异性抗体的类型和效价,比较不同接种途径刺激小鼠体内特异性抗体水平的差异以及相应抗体的体外溶菌活性。结果 pcNspA质粒经滴鼻免疫和肌内注射均可在小鼠体内诱导产生较高的特异性体液免疫水平,尤其是滴鼻免疫途径不仅可诱生较高水平的血清IgG抗体(1∶1600),而且在支气管肺泡洗液和阴道洗液中均可检测到特异性sIgA的存在。而阴道接种pcNspA质粒仅能在阴道局部检测到较低水平的特异性sIgA。用pcNspA质粒诱生的血清IgG抗体做体外溶菌活性实验,证实滴鼻免疫小鼠血清具有溶菌活性。结论淋球菌NspA基因疫苗可在小鼠体内诱导产生特异性抗体,并对机体有免疫保护作用;滴鼻可能是淋球菌NspA核酸疫苗的一个有效接种途径。     

重组CD_(13)单链抗体和蝎毒素多肽AGAP融合蛋白真核表达及对NB4细胞的靶向杀伤作用

目的:本研究应用基因工程技术方法,构建含重组编码CD13单链抗体和蝎毒素镇痛抗肿瘤缬精甘肽(analgesic antitumoral peptide,AGAP)融合蛋白基因的表达载体,并研究CD13-AGAP融合蛋白对CD13阳性白血病细胞NB4影响。方法:克隆东亚钳蝎活性肽AGAP的基因,插入真核表达载体pSecTag2/CD13/RFP,得到pSecTag2/CD13/AGAP重组真核表达载体。酶切及测序鉴定后,脂质体介导重组质粒转染293T细胞,通过RT-PCR和免疫印迹方法检测融合基因和蛋白的表达。纯化融合蛋白,作用NB4细胞,CCK8检测细胞活性,流式细胞仪检测细胞周期。结果:酶切及测序结果证实pSecTag2/CD13/AGAP重组真核表达载体构建成功,转染293T细胞后,RT-PCR和免疫印迹方法结果证实重组质粒得到有效表达,并纯化真核表达融合蛋白CD13-AGAP对血液肿瘤CD13阳性白血病细胞NB4有一定的生长抑制作用,并且使细胞周期G1期阻滞,S期减少。结论:成功构建了融合蛋白真核表达载体pSecTag2/CD13/AGAP,并在293T细胞中成功表达,进一步证实融合蛋白对CD13阳性白...     

雌激素对载脂蛋白AⅠ基因启动子不同区域转录活性的影响

目的:探讨雌激素对载脂蛋白(Apo)AⅠ基因启动子不同区域转录调节活性的影响。方法:利用含荧光素酶报告基因的表达载体pGL2构建携带ApoAⅠ基因启动子不同区域片段的重组质粒和同时携带ApoCⅢ/AⅣ基因片段的重组质粒。阳离子脂质体法将重组质粒与pRL-null内参质粒共转染HepG2细胞,加入10μmol/L雌激素刺激24h检测细胞荧光素酶报告基因的荧光强度,以反映ApoAⅠ的转录水平。结果:pGL2/-256AⅠ,pGL2/-2500AⅠ,pGL2/-256AⅠCⅢAⅣ及pGL2/-2500AⅠCⅢAⅣ转染后雌激素组荧光素酶相对活性明显高于对照组(P<0.05);而pGL2/-41AⅠ及pGL2/-41AⅠCⅢAⅣ质粒转染后雌激素组与对照组荧光素酶活性差异无统计学意义(P>0.05)。结论:ApoAⅠ启动子-256~-41区域可能包含与雌激素作用相关的反应元件,受雌激素刺激后转录活性增强。     

OspA DNA疫苗能保护小鼠抵御伯氏疏螺旋体感染

伯氏疏螺旋体(Borrelia burgdorferi,Bb)是莱姆病的病原体.作者利用真核质粒表达载体VR2210,将编码Bb B31株的外表面蛋白A(OspA)的DNA连接于巨细胞病毒立即早期启动子,将重组质粒免疫小鼠,观 察小鼠是否能产生免疫应答和抵御Bb感染.作者用Pst Ⅰ/XbaⅠ消化VR1012质粒DNA;用Pst Ⅰ/Kpn Ⅰ消化人组织纤溶酶原激活物基因;用Kpn Ⅰ/Xba Ⅰ消化B31OspA.基因,将3个纯化的DNA片段连接起来构建质粒表达载体VR2210.以同法构建OspB质粒表达载体VR2211.将这两种重组质粒分别转化到大肠杆菌内,扩增后用氯化铯-溴化乙锭梯度超离心纯化,再与阳离子脂质体1:1 混和转染人类黑素瘤细胞UM499.用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE)和免疫印迹法分析细胞及上清液,检测体外表达水平.将50μg纯化的质粒与50μl生理盐水混合注射到小鼠的股骨肌,对照组则注射纯B31 rOspA脂蛋白,注射后不同时间取血清进行ELISA检测.     

Enhanced synergistic anti‐Lewis lung carcinoma effect of a DNA vaccine harboring a MUC1‐VEGFR2 fusion gene used with GM‐CSF as an adjuvant

In order to achieve a synergistic effect on anti‐tumour and anti‐angiogenesis activity, we designed and constructed a DNA vaccine that expresses MUC1and VEGFR2 in the same reading frame. The aim of this study was to investigate the anti‐tumour activity of this DNA vaccine. Furthermore, we also investigated the enhanced synergistic anti‐Lewis lung carcinoma effect of this DNA vaccine by using GM‐CSF as an adjuvant. A series of DNA plasmids encoding MUC1, VEGFR2, GM‐CSF, and their conjugates were constructed and injected into mice intramuscularly (i.m.) followed by an electric pulse. The humoral and cellular immune responses after immunization were detected by enzyme‐linked immunosorbent assay (ELISA) and enzyme‐linked immunospot (ELISPOT), respectively. To evaluate the anti‐tumour efficacy of these plasmids, murine models with MUC1‐expressing tumours were generated. After injection into the tumour‐bearing mouse model, the plasmid carrying the fusion gene of MUC1 and VEGFR2 showed stronger inhibition of tumour growth than the plasmid expressing MUC1 or VEGFR2 alone, which indicated that MUC1 and VEGFR2 could exert a synergistic anti‐tumour effect. Furthermore, mice vaccinated with the combination of the GM‐CSF expressing plasmid and the plasmid carrying the fusion gene of MUC1 and VEGFR2 showed an increased inhibition in the growth of MUC1‐expressing tumours and prolonged mouse survival. These observations emphasize the potential of the synergistic anti‐tumour and anti‐angiogenesis strategy used in DNA vaccines, and the potential of the GM‐CSF gene as an adjuvant for DNA vaccines, which could represent a promising approach for tumour immunotherapy.     

Simultaneous targeting of VEGF-receptors 2 and 3 with immunoliposomes enhances therapeutic efficacy

Background: Tumor progression depends on angiogenesis. Vascular endothelial growth factor (VEGF) receptors (VEGFRs) are the main signal transducers that stimulate endothelial cell migration and vessel sprouting. At present, only VEGFR2 is targeted in the clinical practice.

Purpose: To develop new, anti-angiogenic nanoparticles (immunoliposomes, ILs), that redirect cytotoxic compounds to tumor-associated vascular cells.

Methods: Pegylated liposomal doxorubicin (PLD) was targeted against VEGFR2- and VEGFR3-expressing cells by inserting anti-VEGFR2 and/or anti-VEGFR3 antibody fragments into the lipid bilayer membrane of PLD. These constructs were tested in vitro, and in vivo in the Rip1Tag2 mouse model of human cancer.

Results: The combination treatment with anti-VEGFR2-ILs-dox and anti-VEGFR3-ILs-dox was superior to targeting only VEGFR2 cells and provides a highly efficient approach of depleting tumor-associated vasculature. This leads to tumor starvation and pronounced reduction of tumor burden.

Conclusion: Nanoparticles against VEGFR2 and ?3 expressing tumor-associated endothelial cells represent a promising and novel anti-cancer strategy.     

Adjuvant anti-angiogenic therapy enhances chemotherapeutic uptake in a murine model of head and neck cancer*

Abstract

Intratumoural metabolic demands result in excessive angiogenic cytokine release leading to unorganised vasculature. Resultant fluid dynamics oppose blood flow and drug penetration due to a marked increase in interstitial fluid hydrostatic pressure. It is hypothesised that anti-angiogenic therapy may function to ‘prune’ vasculature and lead to improved chemotherapeutic penetration. Subcutaneous, OSC19 tumour bearing mice (n?=?5/dose/agent) were administered varying doses of an anti-mouse VEGFR2 (DC101) or an anti-mouse VEGFR3 (31C1) –3 d, –1 d, 0 d, +1 d and +3 d prior to 200?µg of cetuximab fluorescently labelled with IRDye800CW. Fluorescence imaging of tumours was performed 10 d post cetuximab-IRDye800CW dose to monitor therapeutic uptake. Co-administration of dual anti-angiogenic agents at 50–50%, 75–25% and 25–75% using optimal dose and time (–1 d 10?mg/kg anti-VEGFR2 and –1 d 40?mg/kg anti-VEGFR3) was also evaluated. In order to establish vessel normalisation, NG2 (pericyte marker) and CD31 (endothelial cells) ratios were assessed during immunohistochemical staining of tumour sections. Twenty-mg/kg anti-VEGFR3?+?5?mg/kg anti-VEGFR2 significantly (p?<?.0005) reduced tumour size (–73%) compared to control (59%). The 20?mg/kg anti-VEGFR3?+?5?mg/kg anti-VEGFR2 and 30?mg/kg anti-VEGFR3?+?2.5?mg/kg anti-VEGFR2 significantly (p?<?.0004) improved percent-injected cetuximab-IRDye800CW dose/gram tumour tissue compared to other groups. Adjuvant, dual anti-angiogenic therapy targeting VEGFR2 and VEGFR3 significantly enhances tumour chemotherapeutic uptake compared to control.     

Non-cytolytic antigen clearance in DNA-vaccinated mice with electroporation

Aim： To explore the potential of electroporation （EP）-mediated hepatitis B virus （HBV） DNA vaccination for the treatment of chronic HBV infection. Methods： BALB/c mice were vaccinated with HBV DNA vaccine encoding for the HBV preS2-S antigen, combined with or without EP. HBV surface antigen expression plasmid was administered into mice liver via a hydrodynamic injection to mimic HBV infection. The clearance of antigen in the serum and liver was detected by ELISA assay and immunohistochemical staining. The histopathology of the liver tissues was examined by HE staining and serum alanine aminotransferase assay. Results： The immunogenicity of HBV DNA vaccine encoding for the HBV preS2- S antigen can be improved by EP-mediated vaccine delivery. The elicited immune responses can indeed reduce the expression of HBV surface antigen （HBsAg） in hepatocytes of the mouse model that was transfected to express HBsAg using the hydrodynamic injection method. The antigen clearance process did not cause significant toxicity to liver tissue, suggesting a non-cytolytic mechanism. Conclusion： The EP-aided DNA vaccination may have potential in mediating viral clearance in chronic hepatitis B patients.     

HBsAgDNA疫苗诱导小鼠特异性细胞和体液免疫

目的：观察乙型肝炎病毒（HBV）S区DNA疫苗pCR3．1－S诱导BALB／C小鼠（H-2^d)的特异性免疫应答,及其对稳定表达HBsAg的小鼠肥大细胞瘤细胞P815（P815－HBV-S)成瘤性的影响。方法：肌肉注射DNA疫苗;背部皮下接种P815－HBV－S细胞,观察成瘤情况;ELISA法检测小鼠血清抗HBs;4h^41Cr释放法检测小鼠脾细胞CTL活性。结果：pCR3．1－S 外可表达HBsAg;小鼠接肿该疫苗后血清450nmA值为0．38,强化免疫后达0．87;pCR3．1－S组CTL细胞杀伤活性为51．1％,对照组为20．5％（P＜0．01）。接种P815－HBV－S细胞后对照组成瘤率100％,pCR3．1－S小鼠成瘤率为16．7％,对照组小鼠6周后全部死亡;pCR3．1－S组6周后存活率为87．5％。结论：HBVS区DNA疫苗具有良好的免疫原性,能够诱导小鼠产生特异性体液免疫和细胞免疫应答,对体内HBV感染具有预防及治疗作用。     

单纯疱疹病毒Ⅱ型gD糖蛋白核酸疫苗的构建及免疫观察

目的：构建用于防治单纯疱疹病毒Ⅱ型（HSV-Ⅱ）引起的生殖器疱疹的DNA疫苗。并探讨其免疫保护作用。方法：利用PCR法从HSV-Ⅱ Say株中扩增出gD糖蛋白基因的全部编码序列，将其插入pcDNA3中，构建HSV-Ⅱ gD核酸疫苗，用PCR法、酶切法和测序法进行鉴定；将重组质粒转染COS-7细胞，用原位ELISA检测表达产物；对BALB／c小鼠进行肌肉免疫，用微量细胞中和试验、ELISA、脾T淋巴细胞增殖反应和病毒攻击试验检测免疫效果。结果：构建的HSV-Ⅱ gD核酸疫苗具有良好的免疫原性，对小鼠具有保护作用。结论：本实验成功构建出了具有免疫防御效应的HSV-Ⅱ gD核酸疫苗。     

Esat6-卡介苗重组疫苗的构建免疫原性及抗结核作用的初步研究

目的构建结核分枝杆菌esat6-卡介苗重组疫苗,研究其免疫原性及抗结核作用,以期获得结核病预防性或治疗性疫苗。方法通过基因工程重组技术将结核分枝杆菌保护性抗原esat6的编码基因与穿梭质粒载体pYUB295重组,采用电穿孔技术导入卡介苗中,应用聚合酶链反应(PCR)扩增、聚丙烯酰胺凝胺电泳(PAGE)鉴定重组卡介苗。通过酶联免疫吸附试验(ELISA)法检测其血清中特异性抗体,用MTS法分析其脾淋巴细胞增殖指数。通过观察esat6-卡介苗重组疫苗对结核分枝杆菌感染的预防试验中实验动物半数死亡时间、一定时间内的死亡率、大体病变、T细胞及B细胞免疫功能等指标评价esat6-卡介苗重组疫苗对结核分枝杆菌感染的预防效果。结果PCR扩增、限制性内切酶酶切、DNA测序鉴定、PAGE电泳表明成功地构建了esat6基因pYUB295重组质粒,ESAT6蛋白在卡介苗中分泌表达。重组卡介苗免疫原性试验表明:esat6-卡介苗重组疫苗组有ESAT6特异性抗体产生,45d时达到最高水平。脾淋巴细胞增殖试验表明各组刺激指数均达2.0以上,esat6重组卡介苗免疫组小鼠脾淋巴细胞的刺激指数稍高于对照组。预防试验表明:esat6-卡介苗重组疫苗组、卡介苗组与生理盐水对照组比都能延长结核分枝杆菌感染小鼠的半数死亡时间,降低2个月内的死亡率。其中esat6-卡介苗重组疫苗组效果显著,与卡介苗组比有显著差异。结核分支杆菌攻击后2个月,处死小鼠时,小鼠脏器大体病变及脏器培养结果表明:esat6-卡介苗重组疫苗免疫组小鼠比其他各组小鼠结核菌的负荷轻。抗体检测结果及淋巴细胞增殖实验各组结果差异无统计学意义。结论正确构建了esat6-卡介苗重组疫苗,esat6-卡介苗重组疫苗能提高卡介苗对结核分枝杆菌感染的预防作用。     

单剂HBsAg-PLGA控释疫苗微球小鼠体内免疫学研究

目的研究小鼠皮下注射重组乙型肝炎病毒表面抗原(HBsAg)-乳酸/乙醇酸共聚物(PLGA)微球后的体内抗体应答水平和免疫学机制。方法采用复乳法制备疫苗微球后，单剂注射到BALB/c小鼠皮下，在一定时间内检测全抗体、IgG抗体亚型及细胞因子的应答水平。结果HBsAg-PLGA微球在小鼠体内主要引发体液免疫应答；其中单剂注射HBsAg-PLGA50/50-COOH微球在免疫早期产生较高免疫表达，6周后降低，全抗体水平显著低于常规铝佐剂疫苗(P<0.01)；分别单剂注射HBsAg-PLGA50/50微球及HBsAg-PLGA75/25微球后产生的免疫应答在18周内与铝佐剂疫苗相当(P>0.05)。结论PLGA微球作为乙肝疫苗的长效缓释可生物降解载体，具有一定潜在优势。     

弓形体SAG1基因DNA诱导小鼠体液免疫应答及保护性研究

目的 :用重组真核表达质粒 pc DNA3- SAG1直接免疫 BAL B/ c小鼠 ,观察其 DNA免疫所诱导的小鼠体液免疫反应和保护性作用。方法 :大量制备重组质粒 pc DNA3- SAG1,然后将其导入 BAL B/ c小鼠体内。抗体滴度用 EL ISA法进行测定 :采用 PCR方法对小鼠的血液组织外源基因进行检测 ;对试验组及对照组进行 RH株攻击感染 ,并对其进行分析。结果 :用 EL ISA法检测的抗体 Ig G滴度为 1∶ 2 5 6 0 ;免疫后三周、六个月从免疫鼠的血液组织中用 PCR仍可检测到特异的SAG1基因的存在 :体外弓形虫攻击感染实验组和对照组 ,可见实验组的存活时间较对照组时间延长 (P<0 .0 5 )。结论 :重组质粒 pc DNA3- SAG1免疫 BAL B/ c小鼠可诱导一定的体液免疫应答和一定的保护性作用