人幽门螺杆菌热休克蛋白A亚单位重组蛋白纯化及免疫活性研究

热休克蛋白 (ｈｅａｔｓｈｏｏｋｐｒｏｔｅｉｎ ,Ｈｓｐ)为幽门螺杆菌 (Ｈｐ)共同的抗原成分 ,分为Ａ(ＨｓｐＡ)、Ｂ(ＨｓｐＢ)两个亚单位。目前 ,通过细菌培养获得大量Ｈｐ,并从中纯化出足量的亚单位抗原非常困难。因此 ,我们采用基因工程技术构建重组ＨｓｐＡ基因工程菌 ,并对ＨｓｐＡ重组蛋白纯化条件及免疫学活性进行研究。试验证明ＨｓｐＡ以包涵体形式表达。采用本室建立的包涵体洗涤、溶解方法进行处理 ,溶解包涵体后ＨｓｐＡ纯度大于6 0 % (Ａ级纯化 )。之后我们采用分步稀释法将ＨｓｐＡ复性。对ＨｓｐＡ的Ｂ级纯化选择ＱＳｅｐｈ…     

人内皮抑素克隆表达及对血管内皮细胞生长的抑制 …

目的 获得具有抑制血管内皮细胞生长活性的重组人内皮抑素（ｒｅｃｏｍｂｉｎａｎｔ ｈｕｍａｎ ｅｎｄｏｓｔａｔｉｎ）。方法 从肝细胞中分离总ＲＮＡ,经反转录多聚酶链反应（ＲＴ－ＰＣＲ）得到ｅｎｄｏｓｔａｔｉｎ全基因。用原核细胞表达载体构建了ｐＢＶ２２０／ｅｎｄｏｓｔａｔｉｎ重组质粒,经ＤＮＡ测序确认后,将其转化大肠杆菌ＤＨ５α进行表达、初步纯化及活性测定。结果 经ＳＤＳ－ＰＡＧＥ分析,表达产物相对分     

丙型肝炎病毒核心蛋白基因重组质粒的构建及其在真核 …

目的：构建包含丙型肝炎病毒（ＨＣＶ）核心蛋白（Ｃ）基因片段的重组真核表达载体，并在肝细胞癌细胞株７７２１细胞中表达。方法：将从ｐＢＲＴＭＨＣＶ１－３０１１质粒切下的ＨＣＶ Ｃ基因片段插入ｐｃＤＮＡ３质粒的ＣＭＶ启动子下游，构建真核表达质粒ｐｃＤＮＡＨＣＶ－Ｃ，然后，采用脂质体转染技术，转染７７２１细胞进行瞬时表达，转染细胞裂解煮沸后，通过ＳＤＳ－ＰＡＧＥ及Ｗｅｓｔｅｒｎ ｂｌｏｔ检测表达的核心抗原     

免疫治疗幽门螺杆菌感染后胃形态学的变化

免疫治疗幽门螺杆菌感染后胃形态学的变化［英］／ＭｉｃｈｅｔｔｉＰ…／／Ｈｅｎａｔｏｕ－Ｇａｓｔｒｏｅｎｔｅｒｏｌｏｇｙ－１９９５４２（１１）．－８５应用幽门螺杆菌脲酶和它的重组体亚单位Ａ（ＶｒｅＡ）和／或Ｂ（ＶｒｅＢ）口服免疫可预防小鼠Ｈｆｅｌｌｓ感...     

EphB2配体结合域基因片段的高效表达

目的;对酷氨酸蛋白激酶受体ＥｐｈＢ２胞外的配体结合区基因进行表达研究。方法：编码ＥｐｈＢ２胞外的配体结合区基因片段克隆于ｐＢｕｅｓｃｒｉｐｔＳＫ（－）质粒中,经全自动序列分析仪测正确后,再克隆重组人表达载体ｐＧＥＸ４Ｔ－１,构高效表达克隆ｐＨＴ。转化大肠杆菌ＤＨ５α表达。结果：经ＩＰＴＧ诱导５ｈ,蛋白表达即达高峰,ＳＤＳ ＰＡＧＥ及凝胶密度扫描分析,表达出约４１ＫＤ大小的蛋白,占菌体总蛋白的３５％     

HSV—1 SM44株糖蛋白D基因真核表达载体的构建及其免？…

目的 构建ＨＳＶ－１型ＳＭ４４株糖蛋白Ｄ（ｇＤ）基因的真核表达载体,并用此重组质粒直接免疫小鼠,探讨ＨＳＶ－１ ｇＤ基因作为基因疫苗的可能性。方法 从ＨＳＶ－１基因组中扩增ｇＤ的全编码基因,克隆入载体ｐＵＣ１９中,测序鉴定后转入真核表达载体ｐｃＤＮＡ３．１（＋）。所得重组质粒ｐｃＤ－ＮＡ－ｇＤ以电穿孔法转染ＣＨＯ细胞,并以荧光染色法鉴定表达效果。用ｐｃＤＮＡ－ｇＤ免疫小鼠,ＥＬＩＳＡ法检测基因免疫     

应用重组质粒pAM－HBsAg在果蝇细胞中表达乙型肝炎病毒表面抗原及基因免疫的初步研究

应用果蝇（ＤＳ２）表达系统，构建了含有乙型肝炎病毒表面抗原（ＨＢｓＡｇ）、摄金蛋白启动子（ＭＴｎ－ｐｒｏｍｏｔｅｒ）的共表达质粒ｐＡＭ－ＨＢｓＡｇ，转染细胞，经克隆，存活细胞株的培养上清液经硫酸铵沉淀、氯化铯（ＣＳＣｌ）密度梯度离心沉淀，获得的抗原用酶联免疫吸附试验（ＥＬＩＳＡ）、放射免疫分析（ＲＩＡ）法检测抗体，免疫吸印法（Ｗｅｓｔｅｒｎｂｌｏｔ）和电泳凝胶银染显色证实分子量为２３０００和２７０００，免疫电镜观察显示表达产物为２２ｕｍ球型颗粒，通过重金属离子（ＣｕＳＯ４、ＺｎＳＯ４）的诱导可增加抗原的表达量。用共表达质粒ｐＡＭ－ＨＢｓＡｇ的ＤＮＡ，注射Ｂａｌｂ／Ｃ小鼠的股四头肌。经ＥＬＩＳＡ、ＲＩＡ检测抗体产生情况，结果免疫后的小鼠经硫酸锌喂养抗体高于普通喂养的小鼠。Ｓｏｕｔｈｅｒｎ杂交证实鼠肌肉细胞存在ＨＢｓＡｇ基因。小鼠免疫接种实验表明，ＤＳ２细胞表达的抗原与直接用ＤＮＡ含有ＨＢｓＡｇ的重组质粒）免疫小鼠均获抗ＨＢｓＡｇ的抗体。     

含有丙型肝炎病毒核心基因表达质粒的构建及其基因免疫

目的：研究丙型肝炎病毒（ＨＣＶ）核心（Ｃ）基因免疫诱生特异性免疫应答的可行性。方法：将ＨＣＶ Ｃ基因片段插入真核表达载体ｐｃＤＮＡ３质粒ＣＭＶ启动子的下游,构建真核表达载体ｐｃＤＮＡＨＣＶ－Ｃ,分别转染小鼠骨髓瘤细胞ＳＰ２／０和人肝癌细胞７７２１进行瞬时表达,用免疫荧光法和Ｗｅｓｔｅｒｎ－ｂｌｏｔ检测表达产物,将重组质粒注射,ＢＡＬＢ／ｃ（Ｈ－２＾ｄ）小鼠股四头肌,ＥＬＩＳＡ法检测血清中抗体产生水     

通过受体介导法将核酶特异导入肝细胞以阻断HBV蛋白表达的初步研究

应用半乳糖末端糖蛋白受体（ＡＳＧＰ－Ｒ）介导的内吞作用，将外源基因导入真核细胞，与脂质体介导的转染和细胞表面转铁蛋白受体（Ｔｆ－Ｒ）介导的内吞作用相比，虽然三种方式均能有效介导外源基因的转移，但ＡＳＧＰ－Ｒ法具有肝细胞特异性，而脂质体法和Ｔｆ－Ｒ法不具此特性。将克隆于真核表达载体的针对乙型肝炎病毒（ＨＢＶ）ｍＲＮＡＰｒｅＣ／Ｃ区的核酶质粒ｐＣＭＶ－Ｒｉｐｃ特异性导入肝细胞并发挥作用，通过酶联免疫吸附法（ＥＬＩＳＡ）检测细胞培养液中的乙型肝炎表面抗原（ＨＢｓＡｇ）和ｅ抗原（ＨＢｅＡｇ），评价核酶在细胞水平对ＨＢＶ抗原表达的阻断作用。结果表明当核酶质粒ｐＣＭＶ－Ｒｉｐｃ与ＨＢＶ抗原表达质粒ｐＵＣ－２ＨＢＶ共转染ＨｅｐＧ２细胞时，核酶对ＨＢｓＡｇ和ＨＢｅＡｇ表达的抑制率分别为５５．２９％和６８．７３％。     

重组HBsAg免疫逃逸突变体的表达及其抗原性分析

为了深入研究乙型肝炎病毒S基因变异所致的包膜抗原抗原性的改变，从含ＨＢＶＤＮＡ双拷贝的质粒载体ｐＥｃｏｂ６，获得一个８３７ｂｐ的ＨＢＶ－Ｓ基因片段，将其插入至载体ｐＢｌｕｅｓｃｒｉｐｔ ＫＳ~＋的ＳｍａⅠ位点，通过体外寡核苷酸介导的人工定点突变分别获得第１４５位、１２６位和第１４５位＋１２６位氨基酸三种Ｓ基因变异型。然后将这些Ｓ基因变异片段克隆到真核表达载体ｐＭＥｐ４上，从而构建了含ＨＢＶ－Ｓ基因及其突变型的表达载体ＰＭＥｐ４ＨＢＶＳＭ。用其转染人肝癌细胞系ＨｅｐＧ２，获得稳定分泌ＨＢｓＡｇ及其变异体的抗性细胞系。经体外初步研究表明，ＨＢｓＡｇ １４５位氨基酸变异体可影响ＨＢｓＡｇ的“ａ”抗原决定簇的结构。     

幽门螺杆菌热休克蛋白A亚单位与大肠杆菌不耐热肠毒素B亚单位融合蛋白表达的研究

目的：获得大肠杆菌不耐热肠毒素B亚单位（LTB）与幽门螺杆菌保护性抗原热休克蛋白A亚单位（HspA）的融合蛋白。方法：PCR扩增ltB和hspA基因，依次构建至表达载体pIM-1，转化大肠杆菌，SDS-PAGE、免疫印迹分析目的蛋白表达情况。采用GM1ELISA和D( )-半乳糖亲和层析方法检测重组LTB-HspA融合蛋白LTB组分与GM1神经节苷脂结合活性。结果：重组LTB-HspA融合蛋白表达量最高可达细菌总蛋白的25％。免疫印迹检测结果证实为重组LTB-HspA融合蛋白。GM1ELISA和D( )-半乳糖亲和层析方法检测结果证实重组LTB-HspA融合蛋白具有与GM1神经节苷脂结合的活性。结论：LTB-HspA融合蛋白的表达研究，为研制幽门螺杆菌分子内佐剂疫苗打下了基础。     

重组幽门螺杆菌热休克蛋白A亚单位的高效表达及其初步纯化

目的 在大肠杆菌中高效表达幽门螺直菌的热休克蛋白A基因（hspA)，并对其初步纯化。方法 用巢式PCR扩增hspA基因。经测序证实后，克隆于表达载体pIM-1中，转化大肠杆菌。以SDS－PAGE和免疫印迹分析目的蛋白的表达，并测定N－端氨基酸的序列。采用固相镍离子亲和层析，对重组hspA进行初步纯化。结果 扩增的hspA基因为357bp，并在大肠杆菌中得到高效可溶性表达。重组蛋白的表达量最高可达细菌总蛋白的60．5％。免疫印迹及氨基酸测序结果证实，表达产物为幽门螺杆菌hspA亚单位。固相镍离子亲和层析初步纯化的重组HspA的纯度为87．8％，结论 hspA亚单位的高效表达与初步纯化，为批量获得Hp亚单位抗原打下了基础。     

中国人幽门螺杆菌尿素酶B亚单位的基因克隆及序列分析

目的 克隆人幽门螺杆菌（ｈｅｌｉｃｏｂａｃｔｅｒ ｐｙｌｏｒｉ,Ｈｐ）尿素酶Ｂ基因（ｕｒｅＢ）,并分析其核苷酸序列的特性。方法 用ＰＣＲ技术从临床分离的Ｈｐ菌株基因组中扩增出ｕｒｅＢ基因,将其克隆至ｐＨＰ质粒上进行序列分析。结果 克隆得到的ｕｒｅＢ基因长度为１７１３ｂｐ,其核苷酸序列与ＧｅｎＢａｎｋ公布的序列有６１个碱基存在差异,同源为９６４４％,推定的氨基酸序列同源性为９９．６５％。结论：我们所     

Expression of catalytically active recombinant Helicobacter pylori urease at wild-type levels in Escherichia coli.

The genes encoding Helicobacter pylori urease, a nickel metalloenzyme, have been cloned and expressed in Escherichia coli. Enzymatic activity, however, has been very weak compared with that in clinical isolates of H. pylori. Conditions under which near wild-type urease activity was achieved were developed. E. coli. SE5000 containing recombinant H. pylori urease genes was grown in minimal medium containing no amino acids, NiCl2 was added to 0.75 microM, and structural genes ureA and ureB (pHP902) were overexpressed in trans to the complete urease gene cluster (pHP808). Under these conditions, E. coli SE5000 pHP808/pHP902) expressed a urease activity up to 87 mumol of urea per min per mg of protein (87 U/mg of protein), a level approaching that of wild-type H. pylori UMAB41 (100 U/mg of protein), from which the genes were cloned. Poor catalytic activity of recombinant clones grown in Luria broth or M9 medium containing 0.5% Casamino Acids was due to chelation of nickel ions by medium components, particularly histidine and cysteine. In cultures containing these amino acids, 63Ni2+ was prevented from being transported into cells and was not incorporated into urease protein. As a consequence, M9 minimal medium cultures containing histidine or cysteine produced only 0.05 and 0.9%, respectively, of active urease produced by control cultures containing no amino acids. We conclude that recombinant H. pylori urease is optimally expressed when Ni2+ transport is not inhibited and when sufficient synthesis of urease subunits UreA and UreB is provided.     

人幽门螺杆菌18 000外膜蛋白与HspA双价疫苗的构建和表达

目的 :构建含人幽门螺杆菌 (Hp)热休克蛋白A(HspA)和Mr为 180 0 0的外膜蛋白编码基因的重组载体 ,进行核苷酸序列分析 ,并在E .coliBL2 1中表达。方法 :用PCR方法从HpDNA染色体中 ,扩增HspA编码基因片段。将目的基因HspA与载体 pET32a( )分别经kpnⅠ和BamHI双酶切后 ,进行连接、测序。同时将重组载体 pET32a( ) /HspA和pET32a( ) /Omp18,分别经HindIII和BamHI双酶切 ,通过凝胶电泳回收pET32a( ) /HspA和Mr180 0 0OMPDNA片段 ,经T4连接酶将HspA和Mr180 0 0OMP编码基因通过酶切粘端进行连接 ,而后转化并筛选含有两种目的基因的重组载体 ,并在大肠杆菌BL2 1(DE30 )中表达。表达产物经Ni NTA琼脂糖树脂纯化后 ,以Westernblot分析其抗原性。结果 :经酶切、测序表明 ,插入的基因片段为HpHspA和Mr 为 180 0 0OMP编码基因 ,由 891个碱基组成 ,与GenBank中登录的序列相比较 ,有 1.15 %的碱基发生变异 ,1.2 6 %的氨基酸残基改变。经SDS PAGE分析发现 ,融合基因表达的蛋白Mr 为 5 1× 10 3 ,其中 pET32a( )表达的蛋白Mr 约为 2 0×10 3 ,可溶性表达产物占菌体总蛋白的 18.96 %。重组蛋白经Ni NTA琼脂糖树脂纯化后 ,其纯度达 95 %以上。用Westernblot分析显示 ,该重组蛋白可被Hp阳性患者的血清及抗Mr为 180 0 0OMP单     

大肠杆菌表达人幽门螺杆菌尿素酶B亚单位跨膜区成份

目的 重组表达人幽门螺杆菌尿素酶B亚单位跨膜区成份。方法 采用DNA重组技术将尿素酶B亚单位3’端732bp基因片段克隆至pET11C载体上，转化宿主菌BL21（DE3）E.coli,IPTG诱导，SDS-PAGE及Western-blot分析表达情况。结果 成功构建了含UreB0.7kb片段的重组质粒pET-UreB0.7，并表达了具有免疫反应性的分子量约28000u的重组蛋白，表达率为19.8%。结论 重组的尿素酶B亚单位跨膜区成份为研究其相关生物学特性奠定了重要基础。亦可作为Hp疫苗的成分用于Hp感染的预防和治疗。     

Recombinant antigens prepared from the urease subunits of Helicobacter spp.: evidence of protection in a mouse model of gastric infection.

Urease is an important virulence factor for gastric Helicobacter spp. To elucidate the efficacy of individual urease subunits to act as mucosal immunogens, the genes encoding the respective urease subunits (UreA and UreB) of Helicobacter pylori and Helicobacter felis were cloned in an expression vector (pMAL) and expressed in Escherichia coli cells as translational fusion proteins. The recombinant UreA and UreB proteins were purified by affinity and anion-exchange chromatography techniques and had predicted molecular masses of approximately 68 and 103 kDa, respectively. Western blotting (immunoblotting) studies indicated that the urease components of the fusion proteins were strongly immunogenic and were specifically recognized by polyclonal rabbit anti-Helicobacter sp. sera. The fusion proteins (50 micrograms) were used, in combination with a mucosal adjuvant (cholera toxin), to orogastrically immunize mice against H. felis infection. Gastric tissues from H. felis-challenged mice were assessed by the biopsy urease test and by histology. In mice immunized with recombinant H. felis UreB, 60% of animals (n = 7) were histologically negative for H. felis bacteria after challenge at 17 weeks. This compared with 25% (n = 8) for mice immunized with the heterologous H. pylori UreB antigen. Neither the homologous nor the heterologous UreA subunit elicited protective responses against H. felis infection in mice. The study demonstrated that a recombinant subunit antigen could induce an immunoprotective response against gastric Helicobacter infection.     

幽门螺杆菌尿素酶B亚单位核酸疫苗的构建及鉴定

目的:克隆幽门螺杆菌HpureB基因,并构建其核酸疫苗。方法:以HpNCTC11637株基因组DNA为模板,用PCR扩增ureB基因,并亚克隆至pMD18-T载体中。将目的基因经SalI、BglⅡ酶切纯化后插入pTCAE中,转化E.coliDH5α。经SalI、XhoI酶切并测序鉴定的阳性重组质粒命名为pT-ureB。以电穿孔法将pT-ureB转染CHO细胞,用Wes-tern blot检测UreB蛋白的表达。结果:克隆重组后得到pT-ureB。将pT-ureB以电穿孔法转染CHO细胞后,取其培养上清进行Western blot检测,在UreB的相对分子质量(Mr)为62000处出现特异性条带。结论:成功地构建了HpureB核酸疫苗。体外转染CHO细胞后,经Western blot检测证实有UreB蛋白的表达,为进一步的相关研究奠定了基础。     

表达幽门螺杆菌尿素酶B亚单位的减毒沙门氏菌工程菌株的构建

目的 采用平衡致死系统构建表达幽门螺杆菌尿素酶B亚单位的减毒沙门氏菌工程菌株。方法 PCR扩增幽门螺直菌尿素酶B亚单位,与pYA3149(asd^ ）载体质粒重组,转化减毒的伤寒沙门氏菌突变株,SDS-PAGE,用western-bolt分析其表达,并观察重组菌体外传代培养的稳定性。结果 利用宿主-载体平衡致死系统构建了表达幽门螺杆菌尿素酶B亚单位的重组减毒沙门氏菌工程菌株,且在有选择压力的条件下在体外能稳定地繁殖、生长和传代。结论 表达幽门螺杆菌尿素酶B亚单位的减毒伤寒沙门氏菌工程菌株的成功构建为发展幽门螺杆菌的口服基因工程疫苗奠定了基础。     

Purification of recombinant Helicobacter pylori urease apoenzyme encoded by ureA and ureB.

Helicobacter pylori, a gram-negative, microaerophilic, spiral-shaped bacterium, is an etiologic agent of human gastritis and peptic ulceration and is highly restricted to the gastric mucosa of humans. Urease, synthesized at up to 6% of the soluble cell protein, hydrolyzes urea, thereby releasing ammonia, which may neutralize acid, allowing survival of the bacterium and initial colonization of the gastric mucosa. The urease protein is encoded by two subunit genes, ureA and ureB; however, accessory genes are necessary for enzyme activity. H. pylori urease genes were isolated from a cosmid gene bank and subcloned on a 5.8-kb Sau3A partial fragment carrying ureCDAB, corresponding to four open reading frames described by A. Labigne, V. Cussac, and P. Courcoux (J. Bacteriol. 173:1920-1931, 1991). Clones were confirmed as ureas gene sequences by polymerase chain reaction amplification. The recombinant enzyme was purified from the soluble protein of French press lysates of Escherichia coli DH5 alpha(pHP402) by chromatography on DEAE-Sepharose, Phenyl-Sepharose, Mono-Q, and Superose 6 resins. Fractions containing a catalytically inactive apoenzyme were identified by an enzyme-linked immunosorbent assay (ELISA) by using antisera to native UreA (29.5 kDa) and UreB (66 kDa). Purified recombinant urease was indistinguishable from native enzyme on a Superose 6 column and on Coomassie blue-stained sodium dodecyl sulfate-polyacrylamide gels. The protein reacted specifically on Western blots (immunoblots) with anti-UreA and anti-UreB antibodies and was recognized with an intensity equal to that of the native enzyme in an ELISA using human sera. Clones containing only ureA and ureB also produced an assembled but inactive enzyme. Enzyme activity was not restored by in trans complementation with cloned urease accessory gene sequences from Proteus mirabilis or Morganella morganii. H. pylori urease genes (ureCDAB) subcloned into pACYC184 were also not complemented with any of 1,000 cosmid clones containing H. pylori chromosomal sequences. However, larger clones containing 4.5 kb of DNA downstream of ureB synthesized catalytically active urease when grown in minimal medium. These data indicate that the ureA and ureB genes encoding H. pylori urease are transcribed and translated in E. coli and that these genes alone are sufficient for the synthesis and assembly of the native size enzyme. Genes downstream of ureB, however, are necessary for production of a catalytically active urease.