Construction and expression of the recombinant plasmid pET32α-Sj26GST of Schistosoma japonicum in Escherichia coli BL21(DE3)

Objective To construct and express the recombinant plasmid pET32α-Sj26GST of Schistosoma japonicum(sj)in Escherichia coli(E.coli)B121(DE3).Methods The total RNA was extracted from sj adult worms by ultrasound-breaking,Sj26GST antigen gene was amplified by RT-PCR from the total RNA,then cloned into prokaryotic expression plasmid pET32α(+) and transformed into E.coli B12(DE3)to construct pET32α-Sj26GST;BL21(pET32α-Sj26GST)WaS induced with isopropyl-β-D-thiogalactopyranosid(IPTG),and the expressed products were analyzed and identified by SDS-PAGE and Western blot.Results The 676 bp Sj26GST gene was successfully amplified by RT-PCR and cloned into pET32α(+)by restriction analysis and PCR identification,the recombinant plasmid pET32α-Sj26GST was successfully constructed;the relative molecular mass of the expressed recombinant protein was approximately 49×103 by SDS-PAGE,and the amount of the expressed protein was 24%of the total bacterial proteins;the fusion protein could be recognized by sera from rabbits infected with sj by Western blot.Conclusions The recombinant plasmid pET32α-Sj26GST is successfully constructed and highly expressed in E.coli in fused form with Trx-tag and His-tag,and the expressed fusion protein shows specific antigenicity.     

Construction and expression of the recombinant plasmid pET32α-Sj26GST of Schistosoma japonicum in Escherichia coli BL21(DE3)

Objective To construct and express the recombinant plasmid pET32α-Sj26GST of Schistosoma japonicum(sj)in Escherichia coli(E.coli)B121(DE3).Methods The total RNA was extracted from sj adult worms by ultrasound-breaking,Sj26GST antigen gene was amplified by RT-PCR from the total RNA,then cloned into prokaryotic expression plasmid pET32α(+) and transformed into E.coli B12(DE3)to construct pET32α-Sj26GST;BL21(pET32α-Sj26GST)WaS induced with isopropyl-β-D-thiogalactopyranosid(IPTG),and the expressed products were analyzed and identified by SDS-PAGE and Western blot.Results The 676 bp Sj26GST gene was successfully amplified by RT-PCR and cloned into pET32α(+)by restriction analysis and PCR identification,the recombinant plasmid pET32α-Sj26GST was successfully constructed;the relative molecular mass of the expressed recombinant protein was approximately 49×103 by SDS-PAGE,and the amount of the expressed protein was 24%of the total bacterial proteins;the fusion protein could be recognized by sera from rabbits infected with sj by Western blot.Conclusions The recombinant plasmid pET32α-Sj26GST is successfully constructed and highly expressed in E.coli in fused form with Trx-tag and His-tag,and the expressed fusion protein shows specific antigenicity.     

日本血吸虫重组Bb(pGEX-Sj26GST-Sj32)疫苗的构建及鉴定

目的构建并鉴定日本血吸虫重组双歧杆菌属两歧双歧杆菌(Bb)(pGEX-Sj26GST-Sj32)疫苗。方法从本室保存的BL21(DE3)(pET28α-Sj26GST-Sj32)重组菌中抽提质粒pET28α-Sj26GST-Sj32,PCR扩增Sj26GST-Sj32融合基因,将该融合基因定向克隆到大肠埃希菌-双歧杆菌穿梭表达载体pGEX-1λT中,构建重组质粒pGEX-Sj26GST-Sj32。将此重组质粒转化至大肠埃希菌BL21(DE3)感受态细胞中,抽提质粒并进行BamHⅠ及EcoRⅠ双酶切,鉴定载体片段及目的基因片段长度。用电穿孔法将重组质粒pGEX-Sj26GST-Sj32转化至Bb,构建重组Bb(pGEX-Sj26GST-Sj32),抽提质粒,进行PCR鉴定。结果 PCR成功扩增出长度为1 991bp的Sj26GST-Sj32融合基因;双酶切证实Sj26GST-Sj32融合基因成功插入质粒pGEX-1λT中;PCR证实从重组Bb(pGEX-Sj26GST-Sj32)疫苗中扩增出1991bp的Sj26GST-Sj32融合基因。结论成功构建重组Bb(pGEX-Sj26GST-Sj32)疫苗。     

日本血吸虫重组质粒pQE30-Sj26GST-Sj32的构建及其在大肠埃希菌BL21(DE3)中的表达

目的构建日本血吸虫重组质粒pQE30-Sj26GST-Sj32,研究该质粒在大肠埃希菌BL21(DE3)中的表达。方法超声粉碎日本血吸虫成虫,提取总RNA,通过RT-PCR扩增获Sj26GST和Sj32抗原编码基因;采用基因拼接法(gene SOEing)剪接Sj26GST和Sj32,得到Sj26GST-Sj32融合基因;将融合基因克隆至原核表达载体pQE30,构建重组质粒pQE30-Sj26GST-Sj32并转化大肠埃希菌BL21,经异丙基硫代-β-D-半乳糖苷(IPTG)诱导表达后用SDS-PAGE和Western blot对表达产物进行分析和鉴定。结果基因拼接法扩增出约1 991 bp的Sj26GST-Sj32融合基因;双酶切和PCR鉴定证实Sj26GST-Sj32融合基因成功插入pQE30中,SDS-PAGE显示表达产物为分子质量单位约为61 ku的重组蛋白,与预期结果一致,表达的蛋白约占菌体总蛋白的18%;Western blot鉴定重组蛋白能被日本血吸虫感染的兔血清识别。结论成功构建了日本血吸虫重组质粒pQE30-Sj26GST-Sj32,该质粒在大肠埃希菌BL21中获得了高效融合表达,表达的融合蛋白具有抗原特异性。     

日本血吸虫谷胱甘肽-S-转移酶重组质粒的构建及其在大肠埃希菌BL21(DE3)中的表达

目的 构建日本血吸虫谷胱甘肽-S-转移酶(Sj26GST)重组质粒pET32α-Sj26GST,观察该质粒在大肠埃希菌BL21(DE3)中的表达.方法 超声粉碎日本血吸虫成虫,提取总RNA,通过RT-PCR扩增Sj26GST抗原编码基因,克隆至原核表达载体pET32α(+),构建pET32α-Sj26GST,转化大肠埃希菌BL21(DE3),经异丙基硫代-β-D-半乳糖苷(IPTG)诱导表达后,用十二烷基磺酸钠-聚丙烯酰氨凝胶电泳(SDS-PAGE)和Western blot 对表达产物进行分析和鉴定.结果 RT-PCR扩增出676 bp的Sj26GST基因;双酶切和PCR鉴定证实Sj26GST基因成功插入pET32α(+)中,SDS-PAGE分析显示表达产物为相对分子质量约为49×103的重组蛋白,与预期结果一致,表达的蛋白约占菌体总蛋白的24%;Western blot鉴定重组蛋白能被日本血吸虫感染的兔血清识别.结论 成功构建了pET32α-Sj26GST,该质粒在大肠埃希菌BL21中获得了高效融合表达,表达的融合蛋白具有特异的抗原性.     

日本血吸虫重组质粒pET28α-Sj32的构建及其在大肠埃希菌BL21(DE3)中的表达

目的构建日本血吸虫重组质粒pET28α-Sj32,研究该质粒在大肠埃希菌BL21(DE3)中的表达。方法超声粉碎日本血吸虫成虫,提取总RNA,通过RT-PCR扩增Sj32抗原编码基因;将该基因克隆至原核表达载体pET28α,构建重组质粒pET28α-Sj32并转化大肠埃希菌BL21(DE3),经异丙基硫代-β-D-半乳糖苷(IPTG)诱导表达后用SDS-PAGE和Western blot对表达产物进行分析和鉴定。结果RT-PCR扩增出1270bp的Sj32基因;双酶切和PCR鉴定证实Sj32基因成功插入pET28α中,SDS-PAGE分析显示表达产物为分子质量单位约为42ku的重组蛋白,与预期结果一致,表达的蛋白约占菌体总蛋白的24%;Western blot鉴定重组蛋白能被日本血吸虫感染的兔血清识别。结论成功构建了日本血吸虫重组质粒pET28α-Sj32,该质粒在大肠埃希菌BL21中获得了高效融合表达,表达的融合蛋白具有抗原特异性。     

日本血吸虫重组两歧双歧杆菌pGEX-Sj14-3-3疫苗构建及鉴定

目的 构建日本血吸虫重组双歧杆菌属两歧双歧杆菌(Bifidobacterium bifidum,Bb)pGEx-Sj14-3-3疫苗,并进行鉴定.方法 从日本血吸虫成虫中提取总RNA,通过RT-PCR扩增Sj14-3-3抗原编码基因.将Sj14-3-3基因定向克隆到大肠埃希菌-双歧杆菌穿梭表达载体pGEX-1λT中,构建重组质粒pGEX-Sj14-3-3.用重组质粒将大肠埃希菌BL21(DE3)转化为感受态细胞,抽提重组质粒进行双酶切,鉴定载体片段和基因片段长度:采用电穿孔法,用重组质粒pGEX-Sj14-3-3转化Bh,构建Bb(pGEX-Sj14-3-3)疫苗,抽提疫苗的质粒进行PCR鉴定,比较重新构建的pGEX-Sj14-3-3基因片段长度与日本血吸虫成虫中Sjl4-3-3基因片段长度是否相同.结果 RT-PCR扩增出的日本血吸虫成虫Sj14-3-3基因片段长度为399 bp;双酶切鉴定,重组质粒pGEX-Sj14-3-3载体片段长度为4947 bp,Sj14-3-3基因片段长度为399 bp;在重组的Bb(pGEX-Sj14-3-3)疫苗中,得到Sj14-3-3基因片段长度为399 bp,与预期的结果一致.结论 成功构建了日本血吸虫重组Bb(pGEX-Sj14-3-3)疫苗.

Abstract：

Objective To construct and identify recombinant vaccine Bifwlobacterium bifidum(Bb)pGEX-Sj14-3-3 of Schistosoma japonicum(Sj). Methods Total RNA was extracted from adult Sj, antigen encoding gene Sj14-3-3 was amplified by RT-PCR and cloned into Escherichia coli (E. coli)-Bb shuttle expression vector pGEX-1λT to construct recombinant plasmid pGEX-Sj14-3-3. The recombinant plasmid was transformed into E. coli BL21 (DE3).The plasmid was extracted and identified by using BamH I and EcoR I. Then pGEX-Sjl4-3-3 was electroporated into Bb to construct recombinant Bb (pGEX-Sj14-3-3) vaccine. The extracted plasmid of the recombinant Bb (pGEX-Sj14-3-3) vaccine was identified by PCR, and the size of the products was compared with Sj14-3-3 gene of adult worms.Results Sj14-3-3 of 399 bp in length was amplified by RT-PCR. The products were digested by BamH I and EcoR I , and the fragments length of plasmid pGEX-Sj14-3-3 vector was 4947 bp, and of Sj 14-3-3 gene was 399 bp.The product of 399 bp Sj14-3-3 gene was also amplified by PCR from template of the extracted plasmid of the recombinant Bb(pGEX-Sj14-3-3 ) vaccine. The size of the product obtained was just the same as expected.Conclusion The recombinant Bb(pGEX-Sj14-3-3) vaccine of Sj is successfully constructed.     

日本血吸虫重组两歧双歧杆菌(pGEX-Sj32)疫苗构建及鉴定

目的 构建和鉴定日本血吸虫重组两歧双歧杆菌(Bifidobacterium bifidum,Bb)pGEX-Sj32疫苗.方法 从重庆医科大学附属第一医院传染病寄生虫病研究所构建的重组大肠埃希菌BL21 (pET28α-Sj32)中抽提质粒pET28α-Sj32,通过PCR扩增Sj32抗原编码基因;将Sj32基因定向克隆至大肠埃希菌-双歧杆菌穿梭表达载体pGEX-1λT中,构建重组质粒pGEX-Sj32,将该重组质粒转化至大肠埃希菌BL21感受态细胞(DE3),抽提质粒后进行双酶切鉴定;采用电穿孔法,将重组质粒pGEX-Sj32转化至Bb,构建Bb(pGEX-Sj32)疫苗,再从该疫苗中抽提重组质粒pGEX-Sj32,以其为模板进行PCR鉴定.结果 从抽提质粒pET28α-Sj32中PCR扩增出长度约为1 270 bp的Sj32基因片段;重组质粒pGEX-Sj32经双酶切鉴定,获得长度为4 947 bp的载体片段和长度为1 270 bp的Sj32基因片段;以抽提的疫苗质粒pGEX-Sj32为模板进行PCR扩增,得到了长度约为1 270 bp的Sj32基因片段,与预期结果相符.结论 成功构建了日本血吸虫重组Bb(pGEX-Sj32)疫苗.     

日本血吸虫溶血磷脂酶编码基因真核表达载体的构建和表达及鉴定

目的 从日本血吸虫成虫cDNA中扩增出溶血磷脂酶编码基因(Si1539),并亚克隆至真核表达载体pcDNA3.1(+),旨在提取重组抗原进行免疫原性分析,并用于免疫学诊断.方法 提取日本血吸虫成虫总RNA,反转录生成cDNA,PCR法扩增出Sj1539基因,通过克隆载体pGEM-T连接,亚克隆至真核表达载体pcDNA3.1(+),然后转染至人宫颈癌细胞株(HeLa细胞)中表达,表达产物用Western印迹法进行鉴定.结果 Sj1539基因PCR扩增产物片段长度为684 bp.重组质粒pcDNA3.1(+)-Sj1539经BamH I、Xho I双酶切和PCR扩增鉴定,证实Sj1539基因已成功插入.重组质粒pcDNA3.1(+)-Sj1539在HeLa细胞中的表达产物经Western印迹法鉴定能够与日本血吸虫感染的兔血清反应,其相对分子质量(Mr)约为25×103.结论 成功构建了日本血吸虫Si1539基因真核表达载体,并获得了表达产物.

Abstract：

Objective Schistasoma japonicum(S.japonicum)lysophospholipase gene(Sjl539)from cDNA of S japonicum adult worms was amplified and subcloned into eukaryotic expression vector pcDNA3.1(+)for expression of recombinant antigen and immunogenicity analysis.Methods Total RNA of S.japonicum was extracted to generato cDNA by RT-PCR.The Sj1539 gent was amplified.The DNA fragment was subcloned into eukaryofic expression vector pcDNA3.1(+)following insertion and amplification in pGEM-T.The recombinant plasmid was transfected into human cervical carcinoma cell strain(Hela cells)and expression products were identified by Western blotting.Results The size of PCR product was approximately 684 bp.It was confirmed that Sj1539 gene had been inserted successfully by the recombinant plasmid digested with two enzymes and PCR.It was verified that the expression product could react with S.japonicum-infected rabbit serum by Western blotting and the molecular weight was approximately 25×103.Conclusions The eukaryotie expression vector carrying Sj1539 gene has been established and the expression product has been obtained.     

Construction of prokaryotic expression system of ltB-ureB fusion gene and identification of the recombinant protein immunity and adjuvanticity

AIM: To construct ItB-ureBfusion gene and its prokaryotic expression system and identify immunity and adjuvanticity of the expressed recombinant protein.METHODS: The ureB gene from a clinical Helicobacter pylori (H pylon) strain Y06 and the ItB gene from Escherichia coli (E. coli) strain 44851 were linked into ItB-ureB fusion gene by PCR. The fusion gene sequence was analyzed after T-A cloning. A prokaryotic recombinant expression vector pET32a inserted with ltB-ureB fusion gene (pET32a-ltB-ureB) was constructed. Expression of the recombinant LTB-UreB protein (rLTB-UreB) in E. coliBL21DE3 induced by isopropylthio-β-D-galactoside (IPTG) at different concentrations was detected by SDS-PAGE. Western blot assays were used to examine the immunoreaction of rLTB-UreB by a commercial antibody against whole cell of Hpylori and a self-prepared rabbit anti-rUreB serum, respectively,and determine the antigenicity of the recombinant protein on inducing specific antibody in rabbits. GM1-ELISA was used to demonstrate the adjuvanticity of rLTB-UreB.Immunoreaction of rLTB-UreB to the UreB antibody positive sera from 125 gastric patients was determined by using ELISA.RESULTS: In comparison with the corresponding sequences of original genes, the nucleotide sequence homologies of the cloned ltB-ureB fusion gene were 100%. IPTG with different dosages of 0.1-1.0 mmol/L could efficiently induce pET32a-ltB-ureB-E, coli BL21DE3 to express the rLTB-UreB.The output of the target recombinant protein expressed by pET32a-ureB-E.coli BL21DE3 was approximately 35% of the total bacterial proteins, rLTB-UreB mainly presented in the form of inclusion body. Western blotting results demonstrated that rLTB-UreB could combine with the commercial antibody against whole cell of H pylori and anti-rUreB serum as well as induce rabbit to produce specific antibody. The strong ability of rLTB-UreB bindingbovine GM1 indicated the existence of adjuvanticity of the recombinant protein. All the UreB antibody positive sera from the patients (125/125) were positive for rLTB-UreB.CONCLUSION: A recombinant prokaryotic expression system with high expression efficiency of the target fusion gene ltB-ureB was successfully established. The expressed rLTB-UreB showed qualified immunogenicity, antigenicity and adjuvanticity. All the results mentioned above laid a firm foundation for further development of Hpylorigenetically engineered vaccine.     

Construction and characterization of bivalent vaccine candidate expressing HspA and M(r)18,000 OMP from Helicobacter pylori

AIM: To construct a recombinant vector which can express outer membrane protein (OMP) with Mr18 000 and heat shock protein A (HspA) from Helicobacter pylori(H.pylori)in E.coli BL21, and to exploit the possibility for obtaining the vaccine conferring protection from H. pylori infection.METHODS: The target gene of HspA was amplified from H.pylori chromosome by PCR, and then inserted into the prokaryotic expression vector pET32a (+) by restrictive endonuclease enzyme kpn Ⅰ, BamH Ⅰ simultaneously. The recombinant vector was used to sequence, and then together with pET32a (+)/Omp18, digested by restrictive endonuclease enzyme Hind Ⅲ and BamH Ⅰ simultaneously. pET32a(+)/HspA and Omp18 were recovered from 1% agarose gel by gel kit, and ligated with T4 ligase by BarmH Ⅰ digested viscidity end. The recombinant plasmid of pET32a(+)/HspA/Omp18 was transformed and expressed in E. coli BL21 (DE3) under induction of IPTG. After purification, its antigenicity of the fusion protein was detected by Western blot.RESULTS: Enzyme digestion analysis and sequencing showed that the target genes were inserted into the recombinant vector, composed of 891 base pairs, encoded objective polypeptides of 297 amino acid residues. Compared with GenBank reported by Tomb et al, there were 1.3 %and 1.4 % differences in obtained H. pylori nucleotide sequence and amino acid residues, respectively. SDS-PAGE analysis showed that relative molecule mass (Mr) of the expressed product was Mr 51 000,Mr of protein expressed by pET32a (+) was about Mr 20 000, and soluble expression product accounted for 18.96 % of total bacterial protein.After purification with Ni+2-NTA agarose resins, the purification of recombinant fusion protein was about 95 %. Western blot showed that recombinant fusion protein could be recognized by the patients′ serum infected with H. pylori and anti-Omp18 monoclone, suggesting that this protein had good antigenicity.CONCLUSION: The gene coding for H. pylori Mr18 000OMP and HspA was cloned and expressed successfully. The results obtained lay the foundation for development of H.pylori protein vaccine and a quick diagnostic kit.     

Construction of prokaryotic expression system of ItB-ureB fusion gene and identification of the recombinant protein immunity and adjuvanticity

AIM:To construct ItB-ureBfusion gene and its prokaryoticexpression system and identify immunity and adjuvanticityof the expressed recombinant protein.METHODS:The ureB gene from a clinical Helicobacterpylori(H pylon) strain Y06 and the ItB gene from Escherichiacoli (E.coli) strain 44851 were linked into ItB-ureB fusiongene by PCR.The fusion gene sequence was analyzedafter T-A cloning.A prokaryotic recombinant expressionvector pET32a inserted with ItB-ureB fusion gene (pET32a-ItB-ureB) was constructed.Expression of the recombinantLTB-UreB protein (rLTB-UreB) in E.coli BL21DE3 inducedby isopropylthio-β-D-galactoside (IPTG) at differentconcentrations was detected by SDS-PAGE.Western blotassays were used to examine the immunoreaction of rLTB-UreB by a commercial antibody against whole cell of H pyloriand a self-prepared rabbit anti-rUreB serum,respectively,and determine the antigenicity of the recombinant proteinon inducing specific antibody in rabbits.GM_1-ELISA wasused to demonstrate the adjuvanticity of rLTB-UreB.Immunoreaction of rLTB-UreB to the UreB antibody positivesera from 125 gastric patients was determined by using ELISA.RESULTS:In comparison with the corresponding sequencesof original genes,the nucleotide sequence homologies ofthe cloned ItB-ureB fusion gene were 100%.IPTG withdifferent dosages of 0.1-1.0 mmol/L could efficiently inducepET32a-ItB-ureB-E.coli BL21DE3 to express the rLTB-UreB.The output of the target recombinant protein expressedby pET32a-ureB-E.coli BL21DE3 was approximately 35%of the total bacterial proteins,rLTB-UreB mainly presentedin the form of inclusion body.Western blotting resultsdemonstrated that rLTB-UreB could combine with thecommercial antibody against whole cell of H pylori andanti-rUreB serum as well as induce rabbit to producespecific antibody.The strong ability of rLTB-UreB bindingbovine GM_1 indicated the existence of adjuvanticity of therecombinant protein.All the UreB antibody positive serafrom the patients (125/125) were positive for rLTB-UreB.CONCLUSION:A recombinant prokaryotic expression system with high expression efficiency of the target fusiongene ItB-ureB was successfully established.The expressedrLTB-UreB showed qualified immunogenicity,antigenicityand adjuvanticity.All the results mentioned above laid afirm foundation for further development of H pylori geneticallyengineered vaccine.     

Immunogenicity and immunoprotection of recombinant PEB1 in Campylobacter-jejuni-infected mice

AIM： To construct a prokaryotic expression vector carrying Campylobacterjejuni peblA gene and express it in Escherichia coli. Immunoreactivity and antigenicity of rPEB1 were evaluated. The ability of rPEB1 to induce antibody responses and protective efficacy was identified. METHODS： peblA gene was amplified by PCR, target gene and prokaryotic expression ptasmid pET28a （＋） was digested with BamHI and XhoI, respectively. DNA was ligated with T4 DNA ligase to construct recombinant plasmid pET28a（＋）-peblA. The rPEB1 was expressed in E. coli BL21 （DE3） and identified by SDS-PAGE. BALB/c mice were immunized with rPEBI. ELISA was used to detect the specific antibody titer and MTT method was used to measure the stimulation index of spleen lymphocyte transformation. RESULTS： The recombinant plasmid pET28a （＋）-peblA was correctly constructed. The expression output of PEB1 protein in pET28a （＋）-peblA system was approximately 33% of total proteins in E. coil The specific IgG antibody was detected in serum of BALB/c mice immunized with rPEB1 protein. Effective immunological protection with a lower sickness incidence and mortality was seen in the mice suffering from massive C. jejuni infection. CONCLUSION： rPEB1 protein is a valuable candidate for C. jejuni subunit vaccine.     

Construction of prokaryotic expression system of TGF-β1 epitope gene and identification of recombinant fusion protein immunity

AIM: To insert the constructed TGF-β1 epitope gene into the el loop of C-terminus of truncated hepatitis B core antigen to increase TGF-β1 antigenicity in its prokaryotic expression system and to identify immunity of the expressed recombinant protein in order to exploit the possibility for obtaining anti- TGF-β1 vaccine. METHODS: The TGF-β1 encoding epitope gene (the mature TGF-β1 from 78-109 amino acid residues, TGF-β132) was amplified by polymerase chain reaction from the recombinant pGEM-7z/ TGF-β132 vector. The HBcAg gene fragments (encoding HBcAg from 1-71 and 89-144 amino acid residues) were amplified from PYTA1-HBcAg vector. The recombinant vector pGEMEX-1 was used to insert HBcAg1-71, TGF-β132 and HBcAg89-144 into restrictive endonuclease enzyme and ligated with T4 ligase. The fusion gene fragments HBcAg1-71-TGF-β132-HBcAg89-144 were recloned to pET28a(+) and the DNA sequence was confirmed by the dideoxy chain termination method. The recombinant vector pET28a (+)/ CTC was transformed and expressed in E. coli BL21 (DE3) under induction of IPTG. After purification with Ni+2-NTA agarose resins, the antigenicity of purified protein was detected by ELJSA and Western blot and visualized under electron microscope. RESULTS: Enzyme digestion analysis and sequencing showed that TGF-β1 epitope gene was inserted into the el loop of C-terminus of truncated hepatitis B core antigen. SDS-PAGE analysis showed that relative molecular mass (Mr) of the expressed product by pET28a (+)/CTC was Mr 24 600.The output of the target recombinant protein was approximately 34.8% of the total bacterial protein, mainly presented in the form of inclusion body. Western blotting and ELISA demonstrated that the fusion protein could combine with anti-TGF-β1 polyclonal IgG but not with anti-HBcAg. The purity of protein was about 90 % and the protein was in the form of self-assembling particles visualized under electron microscope. This fusion protein had good anti-TGF-β1 antigenicity and could be used as anti-TGF-β1 vaccine. CONCLUSION: A recombinant prokaryotic expression system with high expression efficiency of the target TGF-β1 epitope gene was successfully established. The fusion protein is in the form of self-assembling particles and HBcAg can increase the antigenicity of TGF-β1. The expressed TGF-β1 epitope gene shows good immunogenicity and antigenicity.     

Construction of prokaryotic expression system of ureB gene from a clinical Helicobacter pylori strain and identification of the recombinant protein immunity

AIM: To clone ureB gene from a clinical isolate of Helicobacter pyloriand construct a prokaryotic expression system of the gene and identify immunity of the expressed recombinant protein. METHODS: ureBgene from a clinical Hpyloristrain Y06 was amplified by the high fidelity polymerase chain reaction technique. The target DNA fragment amplified from ureB gene was sequenced after T-A cloning. Prokaryotic recombinant expression vector pET32a inserted with ureB gene (pET32a-ureB) was constructed. The expression of recombinant UreB protein (rUreB) in E. coli BL21DE3 induced by isopropylthio-β-D-galactoside (IPTG) at different concentrations was examined by SDS-PAGE. Western blot using commercial antibodies against whole cell of Hpylori and an immunodiffusion assay using a self-prepared rabbit anti-rUreB antibody were applied to determine immunity of the target recombinant protein. ELISA was used to detect the antibody against rUreB in sera of 125 Hpyloriinfected patients and to examine rUreB expression in 109 Hpylori isolates. RESULTS: In comparison with the reported corresponding sequences, the nucleotide sequence homology of the cloned ureB gene was from 96.88-97.82% while the homology of its putative amino acid sequence was as high as 99.65-99.82%. The rUreB output expressed by pET32a-ureB-BL21DE3 was approximate 30% of the total bacterial proteins, rUreB specifically combined with the commercial antibodies against whole cell of Hpylori and strongly induced rabbits to produce antibody with a 1:8 immunodiffusion titer after the animals were immunized with the recombinant protein. Serum samples from all Hpyloriinfected patients were positive for UreB antibody and UreB expression were detectable in all tested Hpyloriisolates. CONCLUSION: A prokaryotic expression system with high expression efficiency of Hpylori ureBgene was successfully established. The expressed rUreB showed qualified immunoreactivity and antigenicity. High frequencies of UreB expression in different Hpyloriisolates and specific antibody against UreBin sera of Hpyloriinfected patients indicatet hat UreB is an excellent antigen candidate for developing H pylori vaccine.     

Fusion expression of Helicobacter pylori neutrophil-activating protein in E.coli

AIM: To produce a recombinant protein rMBP-NAP, which was fusionally expressed by Helicobacter pylori (H pylori) neutrophil-activating protein (NAP) and E. coli maltose binding protein (MBP) and to evaluate its immunoreactivity and immunogenicity. METHODS: Neutrophil-activating protein gene of H pylori (HP-napA) was subcloned from the recombinant plasmid pNEB-napA, and fused to MalE gene of expressing vector pMAL-c2x. The recombinant plasmid pMAL-c2x-napA was confirmed by restriction enzyme digestion, and then transformed into E. coli TB1. Fusion protein rMBP-NAP was induced by IPTG and identified by SDS-PAGE analysis. Soluble rMBP-NAP was purified by amylose affinity chromatography. Immunoreactivity and immunogenicity of the fusion protein were evaluated by animal experiment, Western blotting with human H pylori anti-sera. RESULTS: E.coli TB1 carrying recombinant plasmid pMAL-c2x-napA was constructed and led to a high efficiency cytosol expression of fusion protein rBMP -NAP when induced by IPTG. The molecular weight of rBMP-NAP was about 57 kD, accounting for 37.55% of the total protein in the sonicated supematant of E. coli TB1 (pMAL-c2x-napA). The purity of the fusion protein after one-step affinity chromatography was 94% and the yield was 100 mg per liter of bacterial culture. The purified fusion protein could be specifically recognized by both human anti-sera from clinical patients with H pylori infection and rabbit sera immunized by rMBP-NAP itself. CONCLUSION: Recombinant protein rMBP-NAP might be a novel antigen for vaccine development against H pylori.     

日本血吸虫（中国大陆株）Sj16基因的原核表达

目的 进一步研究日本血吸虫（中国大陆株）Sj16的免疫调节功能,丰富有关血吸虫免疫逃避知识。方法 根据曼氏血吸虫Sm16基因已知序列设计合成一对引物,用PCR技术从日本血吸虫（中国大陆株）成虫cDNA文库中扩增Sj16基因,将Sj16基因定向克隆入pGEX-4T-1,转化感受态BL21/DE3菌;用酶切、PCR扩增鉴定筛选得到的重组阳性克隆,IPTG诱导pGEX-4T-1-Sj16转化的BL21/DE3菌,用SDS-PAGE和Wester-blot分析表达产物。结果 从日本血吸虫（中国大陆株）成虫cDNA文库中获取Sj16基因,重组质粒中含有Sj16基因,成功构建日本血吸虫（中国大陆株）Sj16基因原核表达重组质粒pGEX-4T-1-Sj16,pGEX-4T-1-Sj16转化的BL21/DE3菌经IPTG诱导可表达与GST融合的蛋白（约40kDa）,抗GST抗体能特异性识别该蛋白。结论 成功原核表达了Sj16蛋白,为深入研究Sj16的免疫调节功能,丰富有关血吸虫免疫逃避知识打下了基础。     

周期型马来丝虫3-磷酸甘油醛脱氢酶/半胱氨酸蛋白酶抑制剂复合基因真核重组质粒的构建与表达

目的 构建周期型马来丝虫3-磷酸甘油醛脱氰酶/半胱氨酸蛋白酶抑制剂(GAPDH/CPI)复合基因真核重组表达质粒,为研制复合多价疫苗奠定基础.方法 依据GenBank中BmGAPDH及BmCPI基因序列设计引物,以周期型马来丝虫总RNA为模板,RT-PCR扩增目的 编码基因.PCR产物经TA克降后,克隆至载体pGEM-T Easy中.取阳性重组质粒pGEM-T/BmGAPDH和pGEM-T/BmCPI以及真核重组表达载体分别双酶切,将酶切后的载体和目的 片段进行连接,构建真核重组表达质粒pcDNA3.1(+)/BmGAPDH/BmCPI.将复合基因重组质粒瞬时转染人HeLa细胞后,进行RT-PCR验证,将表达产物用十二烷基磺酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE)进行分析和鉴定.结果 分别克隆了pGEM-T/BmGAPDH和pGEM-T/BmCPI重组质粒,经酶切鉴定分别得到877、621 bp特异性片段,与预期值吻合.成功构建了复合基因重组真核表达载体pcDNA3.1(+)/BmGAPDH/BmCPI,酶切鉴定所产生的片段大小与预期吻合.复合基因真核重组表达质粒转染HeLa细胞后得到高水平表达,SDS-PAGE分析显示重组蛋白相对分子质量(Mr)约为54×103.结论 成功构建了周期型马来丝虫GAPDH/CPI复合基因重组表达质粒,并在哺乳动物细胞内得到正确表达.

Abstract：

Objective To construct the eukaryotic expression plasmid containing glyceraldehydes-3-phosphate dehydrogenase (GAPDH) and cysteine protease inhibitor ( CPI ) gene from periodic Brugia malayi (Bm) and to lay foundation for studying multivalent vaccines. Methods Total RNA was extracted from periodic Bin. The BmGAPDH and BmCPI genes were amplified by RT-PCR. The PCR product was cloned and then subeloned into eukaryotic recombinant plasmid vector pcDNA3.1 (+). pcDNA3.1 (+)/BmGAPDH/BmCPI was constructed. The recombinant plasmids were screened and identified by digestion with restriction enzyme and PCR amplification, and were transformed into HeLa cell subsequently. The transient expression of BmGAPDH and BmCPI were examined by RT-PCR. The expressed protein was identified by sodium dodeeylsulphate-polyacrylamide gel electrophoresis(SDS-PAGE). Results Two specific bands of around 877 bp of BmGAPDH and 621 bp of BmCPI were amplified, consistent with the expected value. The same bands were obtained by double restriction enzyme digestion of recombinant plasmids or PCR using recombinant plasmid as template. BmGAPDH and BmCPI mRNA were highly expressed in transfeeted HeLa cell. The relative molecular mass (Mr) of the recombinant protein was about 54 × 103. Conclusion The recombinant eukaryotic expression plasmid pcDNA3.1 (+)/BmGAPDH/BmCPI has been constructed successfully and the protein is expressed correctly in mammalian cell.     

Construction of prokaryotic expression system of ureB gene from a clinical Helicobacter pylori strain and identification of the recombinant protein immunity

AIM:To clone ureB gene from a clinical isolate ofHelicobacter pylori and construct a prokaryotic expressionsystem of the gene and identify immunity of the expressedrecombinant protein.METHODS:ureB gene from a clinical H pylori strain Y06was amplified by the high fidelity polymerase chain reactiontechnique.The target DNA fragment amplified from ureBgene was sequenced after T-A cloning.Prokaryoticrecombinant expression vector pET32a inserted with ureBgene (pET32a-ureB) was constructed.The expression ofrecombinant UreB protein (rUreB) in E.coli BL21DE3induced by isopropylthio-β-D-galactoside (IPTG) at differentconcentrations was examined by SDS-PAGE.Western blotusing commercial antibodies against whole cell of H pyloriand an immunodiffusion assay using a self-prepared rabbitanti-rUreB antibody were applied to determine immunityof the target recombinant protein.ELISA was used to detectthe antibody against rUreB in sera of 125 H pylori infectedpatients and to examine rUreB expression in 109 H pyloriisolates.RESULTS:In comparison with the reported correspondingsequences,the nucleotide sequence homology of the clonedureB gene was from 96.88-97.82% while the homology of itsputative amino acid sequence was as high as 99.65-99.82%.The rUreB output expressed by pET32a-ureB-BL21DE3 wasapproximate 30% of the total bacterial proteins,rUreBspecifically combined with the commercial antibodiesagainst whole cell of H pylori and strongly induced rabbitsto produce antibody with a 1:8 immunodiffusion titer afterthe animals were immunized with the recombinant protein.Serum samples from all H pylori infected patients werepositive for UreB antibody and UreB expression weredetectable in all tested H pylori isolates.CONCLUSION:A prokaryotic expression system with highexpression efficiency of H pylori ureB gene was successfullyestablished.The expressed rUreB showed qualifiedimmunoreactivity and antigenicity.High frequencies of UreB expression in different Hpyloriisolates and specific antibodyagainst UreB in sera of H pylori infected patients indicatethat UreB is an excellent antigen candidate for developingH pylori vaccine.