幽门螺杆菌中性粒细胞激活蛋白DNA疫苗的构建及其免疫保护作用

目的:构建携带幽门螺杆菌中性粒细胞激活蛋白(Hp neutrophil-activating protein,Hp-NAP)基因(napA)活减毒鼠伤寒沙门菌重组DNA疫苗,初步观察其对慢性Hp感染的免疫保护作用.方法:应用基因工程技术扩增全长napA,测序并经同源性分析后,将其亚克隆入真核表达载体pIRES,鉴定正确后将重组质粒转化活减毒鼠伤寒沙门菌构建Hp-NAP口服DNA疫苗.口服Hp-SS1建立SS1长期感染小鼠模型,30周后随机均分为3组,每组各5只.治疗组予109cfu/0.4 ml疫苗菌灌胃,1次/周×3周;2个对照组分别予等体积生理盐水或空白质粒.末次免疫4周后行快速尿素酶检测,ELISA测定血清抗体效价.结果:重组真核表达质粒pIRES-napA成功转化活减毒鼠伤寒沙门菌SL7207;所克隆napA与GenBank中SS1-na-pA核苷酸和蛋白质的同源性均＞98%.免疫后4周治疗组75%(3/4)小鼠快速尿素酶检测阴性,对照组均阳性,差异显著(P＜0.05);治疗组血清抗Hp-NAP抗体效价明显升高.结论:成功构建了具有较好免疫保护作用的Hp-NAP口服重组DNA疫苗,为进一步研制多价抗Hp核酸疫苗奠定了基础.     

表达幽门螺杆菌UreB减毒鼠伤寒沙门氏菌对小鼠的免疫保护作用

目的：构建表达幽门螺杆菌（Helicobacter pylori,H.pylori)尿素酶B亚单位（UreB)减毒鼠伤寒沙门氏疫苗菌,研究其对小鼠抗H.pylori的免疫保护作用。方法：用PCR扩增ureB,将其克隆入高效原核表达质粒pTrc99A,进行基因测序,重组质粒鉴定后导入减毒鼠伤寒沙门氏菌SL3261。用SDS聚丙烯安凝胶电泳、Western blot和薄层扫描进行目的蛋白表达分析。C57BL／6小鼠用重组菌免疫,4周后用H.pyloriSS1攻击,再4周后处死小鼠,取胃做快速尿素酶试验和H.pylori定量培养,对照观察免疫效果。结果：构建了携带ureB的重组原核表达质粒pTrc99A-ureB,并将它成功转化了减毒鼠伤寒沙门氏菌SL3261。重组菌SL3261(pTrc99A-ureB）表达了约66ku的UreB。与对照组相比,重组菌免疫组H.lpylori定植水平明显下降（P＜0．05）。结论：构建了表达H.pylori UreB的重组减毒鼠伤寒沙门疫苗菌,该菌株对C57BL／6有免疫保护作用。     

表达幽门螺杆菌UreB减毒鼠伤寒沙门氏菌对小鼠的免疫保护作用

[目的]构建表达幽门螺杆菌(Helicobacterpylori,Hplori)尿素酶B亚单位(UreB)减毒鼠伤寒沙门氏疫苗菌,研究其对小鼠抗H.pylori的免疫保护作用.[方法]用PCR扩增ureB,将其克隆入高效原核表达质粒pTrc99A,进行基因测序,重组质粒鉴定后导入减毒鼠伤寒沙门氏菌SL261.用SDS聚丙烯酰胺凝胶电泳、Westernblot和薄层扫描进行目的蛋白表达分析.C57BL/6小鼠用重组菌免疫,4周后用H.pyloriSS1攻击,再4周后处死小鼠,取胃做快速尿素酶试验和H.pylori定量培养,对照观察免疫效果.[结果]构建了携带ureB的重组原核表达质粒pTrc99A-ureB,并将它成功转化了减毒鼠伤寒沙门氏菌SL261.重组菌SL3261(pTrc99A-ureB)表达了约66ku的UreB.与对照组比,重组菌免疫组H.pylori定植水平明显下降(P＜0.05).[结论]构建了表达H.pyloriUreB的重组减毒鼠伤寒沙门氏疫苗菌,该菌株对C57BL/6有免疫保护作用.     

幽门螺杆菌尿素酶减毒鼠伤寒杆菌疫苗诱导小鼠黏膜免疫应答的研究

目的研究表达幽门螺杆菌((H．pylori)尿素酶B亚单位(UreB)的减毒鼠伤寒杆菌活菌重组疫苗口服免疫Balb／c小鼠后的黏膜免疫应答状况。方法将已构建成功的表达UreB的重组减毒鼠伤寒杆菌SL3261／pTC01-UreB口服免疫Balb／c小鼠，12周后检测肠液和血清中的特异性抗体反应。结果疫苗组小鼠的肠液和血清中可分别检测到针对UreB的特异性抗体IgA和IgG，病理学检查显示疫苗组小鼠较对照组小鼠胃黏膜炎症程度的差异无统计学意义。结论表达H．pylori UreB的减毒鼠伤寒杆菌SL3261／pTC01-ureB能够诱导小鼠产生抗H．pylori的黏膜免疫，可用作抗H．pylori感染的口服疫苗。     

减毒伤寒杆菌为载体的甲肝疫苗候选株的构建和免疫应答

目的：构建以减毒鼠伤寒杆菌为载体的甲肝疫苗候选株,并证明其免疫源性。方法：将甲型肝炎病毒编码区cDNA插入高效表达质粒pBV221。转化大肠杆菌DH5α。用核酸探针和限制性内切酶筛选和鉴定阳性克隆。将阳性重组质粒用电转移法转化减毒鼠伤寒杆菌BRD509。用抗生素平板筛选法筛选出转化成功的伤寒杆菌,用温度诱导法诱导目的基因在伤寒杆菌中表达。结果：蛋白质印迹法（Western blotting）和酶联免疫吸附测定（ELISA）检测表明,表达蛋白可与人抗甲型肝炎IgG发生特异性反应。用此伤寒杆菌口服或腹腔注射免疫小鼠,小鼠血清检测到抗甲型肝炎病毒的抗体。 结论：以减毒鼠伤寒杆菌为载体的甲肝疫苗构建成功,并可在体内外产生免疫应答。     

携带flk-1的减毒沙门疫苗菌抗胶质瘤血管生成的研究

目的观察表达鼠血管内皮生长因子受体2（VEGFR2，flk-1）的重组减毒鼠伤寒沙门疫苗菌对胶质瘤荷瘤小鼠的抗肿瘤血管及肿瘤生长抑制作用。方法构建真核表达载体pcDNA3、1-flk-1通过电转化法将pcDNA3．1-flk-1导入减毒鼠伤寒沙门菌SL7207中，经由胃管饲于C57BL／6J小鼠，对胶质瘤荷瘤小鼠进行免疫预防及治疗。通过观察免疫动物的生存期，免疫荧光法检测肿瘤血管密度，评价重组疫苗菌的抗血管及肿瘤生长抑制作用。分离免疫小鼠的脾细胞，分析重组疫苗菌免疫后小鼠体内的特异性细胞毒性T细胞（CTL）应答。结果重组疫苗菌免疫能够明显减少肿瘤血管密度，延缓胶质瘤的生长，延长小鼠生存期，获得明显的抗肿瘤效果。重组疫苗菌免疫后可诱导小鼠脾淋巴细胞产生针对flk-1的CTL活性。结论表达鼠flk-1的重组减毒鼠伤寒沙门疫苗菌经口服免疫，可打破小鼠对于自身抗原flk-1的免疫耐受，诱导小鼠产生抗flk-1的特异性免疫反应，特异性杀伤肿瘤血管内皮细胞，预防和治疗小鼠胶质瘤。     

幽门螺杆菌尿素酶减毒鼠伤寒杆菌疫苗诱导小鼠粘膜免疫应答的研究

目的:观察口服减毒鼠伤寒杆菌活菌重组疫苗后小鼠的粘膜免疫应答状况。方法:将已构建成功的表达幽门螺杆菌(H.pylori)尿素酶B亚单位(UreB)的重组减毒鼠伤寒杆菌SL3261/pTC01-UreB口服免疫Balb/c小鼠,12周后检测肠液和血清中的特异性抗体反应。结果:疫苗组小鼠的肠液和血清中可分别检测到针对UreB的特异性抗体IgA和IgG,病理学检查显示疫苗组小鼠较对照组小鼠胃粘膜炎症程度差异无统计学意义。结论:表达H.pyloriUreB的减毒鼠伤寒杆菌SL3261/pTC01-UreB能够诱导小鼠产生抗H.pylori的粘膜免疫,可用作抗H.pylori感染的口服疫苗。     

携带幽门螺杆菌尿素酶B亚单位的重组减毒鼠伤寒沙门菌核酸疫苗的构建

目的 构建含幽门螺杆菌(Hp)尿素酶B亚单位(ureB)基因重组减毒鼠伤寒沙门菌核酸疫苗。方法 抽提Hp标准菌株CCUG17874基因组DNA，应用聚合酶链反应(PCR)技术从基因组DNA扩增ureB基因，克隆入pucmT载体，检测ureB基因序列，经过酶切、连接反应将其克隆入真核表达载体pIRES，转入感受态大肠杆菌DH5α，筛选阳性克隆，通过PCR和酶切反应进行鉴定。重组载体pIRES-ureB转入减毒鼠伤寒沙门菌LB5000，抽提质粒，再次转入SL7207，反复传代，鉴定重组核酸疫苗菌的稳定性。通过脂质体法将构建好的重组载体pIRES-ureB转染COS-7细胞，SDS-PAGE Western印迹法检测pIRES-ureB表达蛋白的免疫原性。结果 扩增出长约1700bp的ureB基因，测序结果表明扩增出的ureB基因与基因库Hp ureB序列一致，PCR和酶切鉴定结果证实ureB基因克隆人真核表达载体pIRES，并成功构建了Hp ureB基因的减毒鼠伤寒沙门菌核酸疫苗，重组核酸疫苗稳定，并且Westem印迹法检测到特异性的蛋白条带。结论 构建了具有免疫反应性的Hp UreB减毒鼠伤寒沙门菌核酸疫苗，为进一步探索其体内的免疫作用奠定了基础。     

携带flk-l的减毒沙门疫苗菌抗胶质瘤血管生成的研究

目的观察表达鼠血管内皮生长因子受体2(VEGFR2,flk-1)的重组减毒鼠伤寒沙门疫苗菌对胶质瘤荷瘤小鼠的抗肿瘤血管及肿瘤生长抑制作用。方法构建真核表达载体pcDNA3 1.-flk-l,通过电转化法将pcDNA3 1.-flk-1导入减毒鼠伤寒沙门菌SL7207中,经由胃管饲于C57BL/6J小鼠,对胶质瘤荷瘤小鼠进行免疫预防及治疗。通过观察免疫动物的生存期,免疫荧光法检测肿瘤血管密度,评价重组疫苗菌的抗血管及肿瘤生长抑制作用。分离免疫小鼠的脾细胞,分析重组疫苗菌免疫后小鼠体内的特异性细胞毒性T细胞(CTL)应答。结果重组疫苗菌免疫能够明显减少肿瘤血管密度,延缓胶质瘤的生长,延长小鼠生存期,获得明显的抗肿瘤效果。重组疫苗菌免疫后可诱导小鼠脾淋巴细胞产生针对flk-l的CTL活性。结论表达鼠flk-l的重组减毒鼠伤寒沙门疫苗菌经口服免疫,可打破小鼠对于自身抗原flk-1的免疫耐受,诱导小鼠产生抗flk-1的特异性免疫反应,特异性杀伤肿瘤血管内皮细胞,预防和治疗小鼠胶质瘤。     

表达幽门螺杆菌过氧化氢酶的无抗性减毒鼠伤寒沙门氏菌株的构建

目的构建表达幽门螺杆菌(Hp)过氧化氢酶的无抗性减毒鼠伤寒沙门氏菌疫苗。方法采用缺失腺苷酸环化酶(△cya)、环腺苷酸受体蛋白(△crp)及天门冬氨酸β-半醛脱氢酶(△asd)的鼠伤寒沙门菌(X4072)作为宿主,将编码过氧化氢酶的基因CAT插入Asd 的组成型表达载体pYA248,通过两次转化引入宿主菌,构建表达过氧化氢酶基因平衡致死的减毒鼠伤寒沙门重组菌X4072(pYA248-CAT)。采用桥联法ELISA测定X4072(pYA248-CAT)培养上清液和裂解上清液中过氧化氢酶的抗原性,参照Meacock的方法及重组菌生长曲线的测定来确定重组菌株的稳定性,通过C57BL/6小鼠口服测定半致死量来确定重组菌的安全性。结果成功构建了表达过氧化氢酶的减毒鼠伤寒沙门菌重组菌株X4072(pYA248-CAT)。桥联法ELISA测定表明重组菌X4072(pYA248-CAT)培养上清中过氧化氢酶的含量高于菌体裂解液;重组菌pYA248-CAT在没有选择压力的情况下培养25代,随机挑选的重组菌全部都能生长,且在ELISA测定过氧化氢酶抗原时均显阳性;重组菌的生长曲线测定表明,X4072(pYA248)和X4072(pYA248-CAT)的生长状态基本一致。口服重组菌株X4072(pYA248-CAT) 1.0×1010 cfu,30 d后C57BL/6存活率仍为100%。结论成功构建了表达过氧化氢酶的无抗性的减毒鼠伤寒沙门菌疫苗X4072(pYA248-CA     

Construction and identification of recombinant attenuated Salmonella typhimurium vaccine strain expressing Helicobacter pylori urease subunit B

Objective To construct a recombinant live attenuated Salmonella typhimurium vaccine strain expressing Helicobacter pylori urease subunit B (ureB).Methods ureB gene was amplified by PCR and cloned into a prokaryotic expression plasmid pTrc99a, and the identified recombinant plasmid was then used to transform an attenuated Salmonella typhimurium vaccine strain SL3261. The ureB expressed in the recombinant vaccine strain was analyzed by SDS-PAGE and optical density scanning. Two and 10 days after recombinant strain intragastric immunization, the C57BL/6 mice were sacrificed, and the spleens and terminal ileums were cultured.Results The ureB gene could be amplified from the recombinant prokaryotic expression plasmid pTrc99A-ureB and the plasmids extracted from transformed SL3261 strain. SDS-PAGE and optical density scanning indicated that ureB was expressed in the recombinant vaccine strain SL3261 (pTrc99A-ureB) as a protein with 66*!kD of molecular weight. Recombinant strain was found in both spleen an terminal ileum of each mouse two and ten days after intragastric immunization.Conclusions A recombinant liver attenuated Salmonella typhimurium vaccine strain expressing Helicobacter pylori ureB was constructed and identified, and this study will help to develop an oral recombinant live vaccine against Helicobacter pylori infection.     

Anti-angiogenesis Effect on Glioma of Attenuated Salmonella Typhimurium Vaccine Strain with flk-1 Gene

To investigate the anti-vasculature effects and the anti-glioma effects of attenuated Salmonella typhimurium vaccine strain expressing VEGFR2 (flk-1) gene, plasmid pcDNA3, 1-flk1 was constructed and electro-transfected into live attenuated Salmonella typhimurium strain SL7207. Mouse models of intracranial G1261 glioblastoma were treated with an orally administered attenuated Salmonella typhimurium expressing flk-1 gene. The survival period was recorded and vessel density was observed by immunofluorescence. CTLs activity was measured by MTT assay. Our results showed that attenuated Salmonella typhimurium vaccine strain expressing flk-1 gene could significantly inhibit glioblastoma growth, reduce vessel density, prolong the survival period and improve the survival rate in these mice. The flk-1 specific CTLs activity was increased obviously after the vaccination. Our study showed that attenuated Salmonella typhlmurium vaccine strain expressing flk-1 gene could break peripheral immune tolerance a in glioma gainst this self-antigen and kill endothelial cells by the orally administered vaccine and can be used for both prophylactic and therapeutic purposes.     

Oral immunization of mice with vaccine of attenuated Salmonella typhimurium expressing Helicobacter pylori urease B subunit

Objective To prepare the live recombinant vaccine of attenuated Salmonella typhimurium SL3261 expressing Helicobacterpylori （H. pylori） B subunit （UreB） and to determine whether it could be used as an oral vaccine against H. pylori infection. Methods Using genomic DNA of H. pylori Sydney strain （SS1） as template, the H. pylori UreB gene fragment was amplified by PCR and subcloned into the expression vector pTC01. The recombinant plasmid pTC01-UreB was then transferred into LBS000 to obtain modified forms, and further conversed into the attenuated Salmonella typhimurium SL3261 to obtain recombinant SL3261/pCT01-UreB as an oral immunization reagent, which was then used to orally immunize Balb/c mice twice at a three-week interval. Twelve weeks later, anti-UreB IgA antibodies in intestinal fluid and IgG antibodies in sera were determined by ELISA. The relating data in control groups （including body weight, gastric inflammation, etc.） were also collected. Results The sequencing analysis showed that the UreB gene fragment amplified by PCR was consistent with the sequence of the H. pylori UreB gene. The restriction enzyme digestion revealed that the correct pTC01-UreB was obtained. SDS-PAGE and Western blot showed that a 61KD protein was expressed in SL3261/pTC01-UreB, which could be recognized by anti-H, pylori UreB antiserum and was absent in the control containing only Salmonella typhimurium SL3261 strain. The multiple oral immunization with SL3261/pTC01-UreB could significantly induce H. pylori specific mucosal IgA response as well as serum IgG responses. IFN-T and IL-10 levels were significantly increased in SL3261/pTC01-UreB group, and no obvious side effect and change in gastric inflammation were observed. Conclusion The attenuated vaccine of Salmonella typhimurium expressing H. pylori UreB can be used as an oral vaccine against H. pylori infection.     

Immune responses in mice to oral administration of attenuated Salmonella typhimurium expressing Helicobacter pylori urease B subunit by a lavage technique

Objective： To determine whether attenuated Salmonella typhimurium producing Helicobacter pylori （Hp） urease subunit B（UreB）can elicit specific immune responses against Hp in mice tested by a lavage technique. Methods： Attenuated Salmonella typhimurium producing Hp UreB immunized orally Balb/c mice twice at a 3-week interval. After 12 weeks, mice intestinal secretions were obtained without harm by administering a lavage solution intragastrically. The mice intestinal secretions of immune group were also directly washed out after the mice were killed. The antibody responses were evaluated by using serum and intestinal fluid with ELISA assay. Results： The multiple oral immunizations with SL3261/pTC01-UreB induced significantly Hp-specific mucosal IgA response as well as serum IgG response. The IgA was also consistently higher in the intestinal fluid obtained by the lavage solution than by direct washout. In addition, no obvious side effects and changes in gastric inflammation were observed in mice. Conclusion： The attenuated Salmonella typhimurium expressing Hp UreB may be used as an oral vaccine against Hp infection. And the lavage technique is an ideal method in the study of mucosal immune responses.     

幽门螺杆菌尿素酶B亚单位基因在减毒鼠伤寒杆菌中的表达

目的：制备能表达幽门螺杆菌（Ｈｐ）尿素酶Ｂ亚单位（ＵｒｅＢ）的减毒鼠伤寒杆菌,初步确定是其否可用作抗ＨＰ的口服疫苗。方法应用ＰＣＲ扩增ＨＰＵｒｅＢ基因片段,测序后克隆入原核表达载体ＰＴｃ０１,转化ＬＢ５０００修饰后再转化ＳＬ３２６１,得到重组的减毒鼠伤寒杆菌ＳＬ３２６１／ＰＴｃ０１－ＵｒｅＢ。应用抗ＨＰ菌体蛋白兔血清行Ｗｅｓｔｅｒｎ－ｂｌｏｔ检测ＵｒｅＢ在ＳＬ３２６１中的表达,ＳＬ３２６１／ＰＴｃ     

表达幽门螺杆菌过氧化氢酶的无抗性减毒鼠伤寒沙门氏菌株的构建

OBJECTIVE: To construct a non-resistant attenuated Salmonella typhimurium (S.typhimurium) strain capable of expressing Helicobacter pylori (Hp) catalase. METHODS: After PCR amplification, the gene fragment encoding Hp catalase was inserted into the expression vector pYA248 containing asd gene, and the recombinant vector was then introduced into the host S.typhimurium strain X4072 depleted of genes encoding adenylate cyclase (delta cya), cyclic adenosine monophosphate receptor protein (delta crp) and aspartate-beta-semialdehyde dehydrogenase (delta asd). Bridged enzyme-linked immunosorbent assay (ELISA) was employed to measure the antigenicity of the catalase expressed in the sonicate and culture supernatant. According to Meacock's method and with the assistance of the growth curve, the stability of the recombinant strain was evaluated. A half lethal oral dose test was conducted to evaluate the safety of recombinant strain. RESULTS: S.typhimurium X4072 (pYA248-CAT) with expected capacity was successfully constructed, and bridged ELISA demonstrated higher catalase levels in the culture supernatant than in the sonicate of the recombinant strain X4072 (pYA248-CAT). After the strain was passaged for 100 generations without selection pressure, all the randomly selected colony of the recombinant strain grew well with positive catalase antigenicity as identified by ELISA. The growth curve of the recombinant strain showed comparable growth status of the 2 strains X4072 (pYA248) and X4072 (pYA248-CAT). The survival rate of C57BL/6 mice was 100% 30 d after oral administration of 1.0x10(10) cfu X4072 (pYA248-CAT). CONCLUSION: Non-resistant S. typhimurium vaccine X4072 (pYA248- CAT) is constructed successfully, which is stable in vitro and safe as confirmed by animal experiment. This vaccine provides a new candidate for viable oral vaccine against Hp infection.     

两种表达鼠精子受精素β蛋白的减毒沙门氏菌疫苗株的稳定性分析

目的 了解表达鼠精子抗原受精素β亚单位(Fertilin βsubumit,fβ)的两种重组减毒沙门氏菌疫苗株X4632(pFEC)和X4550(pFEC)的生长特性和体内外携带重组质粒的稳定性。方法 将两种重组沙门氏菌疫苗株X4632(pFEC)和X4550(pFEC)体外传代培养，观察比较其生长特性和所含重组质粒的稳定性；将该两种重组菌口服免疫BAIB／c雄性小鼠，观察重组菌侵入小鼠Peyer结、肠系膜淋巴结和脾脏等组织内繁殖生长情况和所回收重组菌携带质粒的阳性率。结果 该两种无抗药性的重组菌株在体内、外营养选择压力下均可较稳定携带重组质粒传代繁殖，X4550(pCFL)在体内可较稳定地定植于Peyer结、肠系膜淋巴结和脾脏；X4632(pCFL)可较稳定地定植于Peyer结，均可稳定表达被Fβ单抗识别的重组Fβ蛋日。结论 X4632(pFEC)、X4550(pFEC)疫苗株可作为递呈精子抗原的活菌载体。