利用噬菌体展示技术筛选日本血吸虫模拟抗原表位

目的　从噬菌体肽库筛选日本血吸虫抗原模拟抗原表位。方法　制备亲和纯化的日本血吸虫病人血清抗体 Ig G,用此 Ig G包被酶标板对 12肽库进行反复淘选 ,对获得的目的噬菌体进行鉴定及免疫原性分析。结果　获得一批阳性噬菌体克隆 ,其中一部分与血吸虫病人血清反应产生较高的吸光值 ,Western blotting分析表明这些噬菌体能被血吸虫病人血清所识别 ,具有类似于血吸虫抗原的免疫原性。结论　获得一批具有模拟日本血吸虫抗原表位的噬菌体克隆 ,为今后进一步研究它们在血吸虫病诊断及疫苗研究中的作用奠定了基础。     

噬菌体展示技术筛选人隐孢子虫P23抗原表位

目的本研究利用噬菌体展示技术筛选人隐孢子虫P23抗原表位,为研制其抗原表位疫苗奠定基础。方法首先用人隐孢子虫重组P23抗原免疫动物以制备抗体,将该抗体与噬菌体展示随机肽库结合,通过ELISA和Western-blot方法鉴定阳性克隆,并对阳性克隆进行增殖,然后对其序列测定和抗原表位预测。结果噬菌体肽库结合抗体后,经ELISA方法可鉴定10株为阳性克隆,Western-blot检测可发现有67kD目的条带出现;序列分析结果可发现它们中具有3个不同结构表位序列,命名为ep1,ep2,ep3,且预测出具有良好的亲水性。结论所得序列是具有B细胞抗原表位。     

利用噬菌体展示肽库筛选和鉴定沙门氏菌O9抗原的模拟表位

目的　用生物素标记沙门氏菌O9单克隆抗体 (3- 4 7-O)作为分子探针 ,从两个九肽噬菌体展示文库中筛选鉴定该抗体所识别的抗原模拟表位 ,从而为模拟多糖的多肽疫苗或编码该模拟表位的DNA疫苗研制奠定基础。方法与结果　经过三轮的亲和筛选 ,得到了两个能与O9单抗反应的强阳性单克隆扩增物gm6 2和 gm6 8,其序列分别为SHHVRGGGG和YQKWYLPKS。竞争ELISA实验表明 ,10 10转导单位噬菌体 gm6 8对肠炎沙门氏菌与 3- 4 7-O结合的抑制率达到 6 5 % ,而噬菌体 gm6 2的抑制率仅为 2 0 % ,且 gm6 8可以诱导产生针对沙门氏菌O9的抗体 ,而gm6 2则不能。 结论　实验结果显示九肽YQKWYLPKS是具有免疫原性的O9抗原模拟表位。     

用噬菌体随机肽库鉴定日本血吸虫22.6kDa抗原分子的表位

目的　筛选和鉴定日本血吸虫 (中国大陆株 ) 2 2 .6kDa抗原 (Sj2 2 .6)的表位。　 方法　用纯化的抗Sj2 2 .6的多克隆抗体IgG对噬菌体十二肽库进行 5轮免疫学筛选 ,挑取克隆 ;采用Westernblotting免疫识别 ,将获得的阳性克隆免疫小鼠 ,并采用dot ELISA筛选能刺激小鼠产生较高滴度抗Sj2 2 .6抗体的阳性克隆 ;测定核苷酸序列 ,分析其表位与Sj2 2 .6抗原的同源性。　结果　经 5轮免疫学筛选后挑取的 1 4个克隆 ,用Westernblotting方法均能被抗Sj2 2 .6抗体识别。经动物免疫初步实验筛选 ,共获得 6个免疫原性较强的阳性克隆 ,测序结果获得 4种不同表位 ,其中 1种表位与Sj2 2 .6抗原具有较高的同源性 ,其余 3种表位与其无一级结构的同源性。　结论　获得的 4种日本血吸虫中国大陆株抗原表位 ,1种可能为结构表位 ,3种为模拟表位     

弓形虫微线蛋白16抗原表位区的预测及酵母表面展示

目的应用生物信息学软件预测弓形虫微线蛋白16(TgMIC16)B/T细胞抗原表位并对抗原表位区进行酿酒酵母菌的表面展示。方法利用DNAStar和IEDB对TgMIC16进行B细胞抗原表位预测,利用SYFPEITHI和BIMAS预测其T细胞抗原表位。参照预测结果,采用pCTCON2/EBY100展示系统对抗原表位区进行酵母表面展示,利用间接免疫荧光(IFA)和流式细胞仪检测表达情况。结果 TgMIC16存在潜在的B/T细胞抗原表位且集中在aa343-625区域;该抗原表位区成功展示到酵母细胞表面,最佳诱导时间为24~36h。结论为下一步酵母载体疫苗的研制及疗效评价奠定基础。     

结核杆菌热休克蛋白质70作为乙型肝炎核心抗原细胞毒性T淋巴细胞表位肽载体的研究

目的探讨结核杆菌热休克蛋白质70（TB．HSP70）作为乙型肝炎病毒（HBV）核心抗原细胞毒性T淋巴细胞（CTL）表位肽载体，诱导HBV特异性免疫应答的可能性。方法体外观察重组TB．HSP70-CTL融合蛋白质和TB．HSP70／CTL复合物诱导慢性乙型肝炎患者外周血淋巴细胞增殖以及HBV特异性细胞毒活性；以Balb／c小鼠为体内研究对象，行流式细胞术分析免疫后小鼠外周血和脾细胞中CD4^＋与CD8^＋T淋巴细胞及自然杀伤（NK）细胞的比率，并观察能否诱导HBV特异性免疫保护作用。结果体内外研究表明TB．HSP70-CTL融合蛋白质和TB．HSP70／CTL复合物能有效地诱导HBV特异性细胞毒活性，体内能激活CD4^＋与CD8^＋T淋巴细胞及NK细胞增殖。在体内，TB．HSP70-CTL融合蛋白质较复合物能更有效地激活免疫应答，其杀伤率为28．9％。CD8^＋T淋巴细胞在脾细胞中比率为43．9％，NK细胞为13．6％。而单纯的TB．HSP70和CTL表位肽并不能有效地引起机体的免疫应答。结论TB．HSP70能够作为乙型肝炎核心抗原CTL表位肽的载体，提高小分子表位肽的免疫原性。     

HBV细胞毒性T细胞抗原表位单链三聚体在真核细胞中的表达及其腺病毒载体的构建

目的：构建乙型肝炎病毒表面抗原细胞毒性T细胞抗原表位单链三聚体（HBsAg-SCT）真核表达载体，在真核细胞293T中表达，并构建含HBsAg-SCT的腺病毒载体。方法：合成H-2L。限制的HBsAg细胞毒性T细胞表位寡核苷酸，与H-2L“分子融合，构建含HBsAg—SCT的真核表达载体，并转染293T细胞，采用流式细胞技术观察HB—sAg-SCT在细胞表面的表达。将HBsAg—SCT亚克隆到腺病毒载体，转染293A细胞，包装产生携带HBsAg-SCT的重组腺病毒。结果：成功构建了HBsAg-SCT真核表达载体，并在真核细胞中表达。利用重组腺病毒载体制备出高滴度的重组腺病毒。结论：合HBsAg—SCT的真核表达载体能够在真核细胞表面有效表达，获得合HBsAg-SCT的重组腺病毒，为研究HBsAg—SCT免疫治疗HBV感染打下基础。     

细粒棘球绦虫抗原Fis1T细胞表位肽缓解过敏性哮喘小鼠气道炎症的免疫学作用研究

目的 探讨细粒棘球绦虫Fis1蛋白的T细胞表位肽(Eg.Fis1_83-102)对过敏性哮喘小鼠气道炎症的缓解作用及免疫学作用机制。方法 1)体内试验：将24只6～8周雌性BALB/C小鼠随机分为3组(每组8只),其中B组为对照组,C组为过敏性哮喘组(OVA),T组为干预组(OVA+Eg.Fis1_83-102)。采用ELISA法检测小鼠血清OVA特异性IgE水平;采用HE,PAS,MASSON组织染色检查小鼠肺组织病理变化;采用流式细胞术分析肺脏和脾脏组织中嗜酸性粒细胞比例、Th1和Th2的分群及比例。2)体外试验：采用裂红法分离小鼠脾脏单个核细胞,每孔以1×10⁶个细胞铺板,分为3组(每组3个复孔),其中B组为对照组,C组为刀豆蛋白刺激组(ConA),T组为干预组(ConA+Eg.Fis1_83-102),培养3 d后收集上清,采用ELISA法检测IFN-γ和IL-4水平。结果 1)体内试验：与C组相比,T组小鼠肺组织的炎细胞浸润、胶原沉积等病理损伤有所改善,血清OVA特异性IgE水平、肺组织嗜酸性粒...     

细粒棘球绦虫原头节抗原Eg-01883的B细胞表位预测、筛选及其血清学诊断价值北大核心CSCD

目的应用计算机软件分析细粒棘球绦虫原头节特异性抗原分子Eg-01883,预测其可能形成的B细胞表位,并探讨其B细胞表位的免疫反应性及诊断价值。方法使用在线软件SOPMA及DNAStar分析Eg-01883的二级结构,采用SWISS-Model预测该蛋白的三级结构。应用在线软件ABCPred和IEDB结合其亲水性、柔韧性、表面可及性、抗原性等二级结构和三级结构对其B细胞表位进行分析预测、并人工合成表位肽段;以完整蛋白rEg-01883免疫小鼠产生的抗血清为一抗,采用间接ELISA方法筛选免疫反应性较强的表位,然后再以感染细粒棘球绦虫的小鼠血清为一抗,ELISA检测其免疫反应性,评价其诊断价值。结果初步筛选出7条抗原指数较高的Eg-01883表位,B细胞表位区域位于1-15、19-34、155-169、180-196、216-232、236-248、271-287位氨基酸。合成上述表位,纯度为99.99%。使用完整蛋白免疫血清筛选出2条反应原性较强的优势表位19-34和180-196,细粒棘球蚴感染小鼠血清能识别这两条B细胞表位,A450值结果分别为0.8218±0.0406和0.6398±0.0447,与对照组A_(450)值0.3312±0.0267和0.2961±0.0284比较差异均有统计学意义(P<0.05)。结论成功筛选到两个潜在的B细胞表位诊断抗原肽,对进一步开发细粒棘球绦虫早期诊断抗原和研究优势表位疫苗具有重要意义。     

创伤弧菌溶细胞毒素单克隆抗体制备及其鉴定

目的制备创伤弧菌(Vibrio vulnificus)溶细胞素vvhA基因产物鼠源性单克隆抗体并鉴定其特异性和免疫性,为进一步研制创伤弧菌检测试剂盒奠定基础。方法采用IPTG诱导目的重组蛋白rvvhA表达,Ni-NTA亲和层析法提纯rvvhA,SDS-PAGE检测表达和提纯效果。采用杂交瘤技术和rvvhA-ELISA制备并筛选分泌rvvhA单克隆抗体的细胞株,有限稀释法进行细胞克隆。采用免疫双扩散法鉴定单克隆抗体类型。采用ELISA、免疫双扩散法和Western Blot鉴定单克隆抗体的效价和特异性。结果在0.5mmol/L IPTG诱导下,rvvhA产量可占细菌总蛋白的18%。提纯的rvvhA经SDS-PAGE后仅显示单一的蛋白条带。共获得9株rvvhA抗体阳性的杂交瘤细胞株,其中A5E8和C3B6株可持续分泌高效价特异性单克隆抗体,其抗体类型分别为IgG1和IgG2a。A5E8和C3B6单克隆抗体有较高特异性,与多种其它细菌蛋白不发生免疫反应,对rvvhA及创伤弧菌GTC333株和WZ01株蛋白的ELISA检测阳性的效价可达1∶4000~1∶8000、免疫双扩散效价为1∶4~1∶8,Western Blot结果显示此等单克隆抗体均能有效识别rvvhA。结论本研究成功地获得了2株稳定分泌rvvhA特异性单克隆抗体的鼠源性杂交瘤细胞株,rvvhA单克隆抗体可用于检测自然表达的创伤弧菌溶细胞素。     

Mouse skin damage caused by cytolysin from Vibrio vulnificus and by V. vulnificus infection

Light and electron microscopy of mouse skin damage caused by intradermal infection with a virulent strain of Vibrio vulnificus and by a single intradermal injection of the cytolytic toxin produced by the bacterium revealed similar structural alterations. The epidermis was intact; however, the infection and toxin produced acute cellulitis characterized by extensive extracellular edema; disorganization of collagen bundles; large accumulations of cell debris and plasma proteins; damaged or necrotic fat cells, capillary endothelial cells, and muscle cells; and mild inflammatory cell infiltration. The virulent strain of V. vulnificus produced a capsule and was resistant to phagocytosis in vivo, whereas a weakly virulent strain of the bacterium did not produce a capsule and was readily phagocytized and digested. Factors that may be important in the pathogenesis of V. vulnificus wound infections include a capsule that inhibits phagocytosis and an extracellular cytolytic toxin that is responsible, at least in part, for the severe tissue damage characteristic of such wound infections.     

创伤弧菌溶细胞素基因在大肠杆菌中的表达及溶血活性鉴定

目的用大肠杆菌表达系统表达创伤弧菌溶细胞素,并对其溶血活性进行评价。为今后的免疫学活性研究和单克隆检测试剂盒的研发奠定基础。方法构建pET28a( )-vvhA表达载体,对包涵体进行三步洗涤后,用金属亲合层析(HisTag)纯化重组蛋白,并用溶血试验验证重组蛋白活性。结果用基因工程的方法成功获得高表达、高纯度(纯度≥96%)重组蛋白VVC。利用兔红细胞溶血试验检测表明,重组蛋白具有溶血活性,其活性为0.2μg/HU。结论成功用大肠杆菌表达系统表达创伤弧菌溶细胞素并对其纯化、复性条件进行优化。     

Identification of synovium-specific homing peptides by in vivo phage display selection

OBJECTIVE: To identify homing peptides specific for human synovium that could be used as targeting devices for delivering therapeutic/diagnostic agents to human joints. METHODS: Human synovium and skin were transplanted into SCID mice. A disulfide-constrained 7-amino acid peptide phage display library was injected intravenously into the animals and synovial homing phage recovered from synovial grafts. Following 3-4 cycles of enrichment, DNA sequencing of homing phage clones allowed the identification of specific peptides that were synthesized by a-fluorenylmethyloxycarbonyl chemistry and used in competitive in vivo assays and immunohistochemistry analyses. RESULTS: We isolated synovial homing phages displaying specific peptides that distinctively bound to synovial but not skin or mouse microvascular endothelium (MVE). They retained their tissue homing specificity in vivo, independently from the phage component, the original pathology of the transplanted tissue, and the degree of human/murine graft vascularization. One such peptide (CKSTHDRLC) maintained synovial homing specificity both when presented by the phage and as a free synthetic peptide. The synthetic peptide also competed with and inhibited in vivo the binding of the parent phage to the cognate synovial MVE ligand. CONCLUSION: This is the first report describing peptides with homing properties specific for human synovial MVE. This was demonstrated using a novel approach targeting human tissues, transplanted into SCID mice, directly by in vivo phage display selection. The identification of such peptides opens the possibility of using these sequences to construct joint-specific drug delivery systems that may have considerable impact in the treatment of arthritic conditions.     

Epitope mapping of monoclonal antibodies specific to serovar of Leptospira, using phage display technique

Random heptapeptide library displayed by bacteriophage T7 was used to characterize epitopes of five monoclonal antibodies that were specific to L. australis, L. bangkok, and L. bratislava. Phages selected by biopanning were cloned by plaque isolation, and the binding specificity of individual clones was confirmed by enzyme-linked immunosorbent assay, before being further amplified and checked for phage peptide sequence using PCR and DNA sequencing. Almost all of the peptide epitopes were continuous or linear. Interestingly, in phages reacting with the monoclonal antibody (MAb) clones F11, F20, 2C3D4, and 8C6C4A12, the deduced amino acid sequence of the displayed peptides corresponded to a segment of hypothetical protein of the Leptospira genome (L. interrogans serovar Lai and Copenhageni). Considering the deduced amino acid sequences of phages reacting with the MAb clones F11, F20, 2C3D4, and 8C6C4A12, the consensus motif -SKSSRC-, -TLINIF-, -SSKSYR- and -CTPKKSGRC- appeared respectively. No similarity was observed among phage reacting with the MAb clone F21. The results demonstrate that T7 phage display technique has potential for epitope mapping of leptospiral MAbs, and for rapid analysis of the interactions between phage display peptides with the MAb. The finding of a phage peptide that binds to MAb with protective activity can be further tested as a candidate for leptospirosis vaccine in the future.     

Identification of targeting peptides for ischemic myocardium by in vivo phage display

Therapies selectively targeting ischemic myocardium could be applied by intravenous injection. Here, we report an approach for ischemic tissue-selective targeting based on in vivo screening of random peptide sequences using phage display. We performed in vivo biopanning using a phage library in a rat model of ischemia-reperfusion and identified three peptide motifs, CSTSMLKAC, CKPGTSSYC, and CPDRSVNNC, that exhibited preferential binding to ischemic heart tissue compared to normal heart as well as other control organs. The CSTSMLKAC sequence was capable of mediating selective homing of phage to ischemic heart tissue. The CSTSMLKAC peptide was then made as a fusion protein with Sumo-mCherry and injected intravenously in a mouse model of myocardial ischemia-reperfusion injury; subsequently, bio-distribution of Sumo-mCherry-CSTSMLKAC was measured with quantitative ELISA. The targeting peptide led to a significant increase in homing to ischemic left ventricle compared to tissues from non-ischemic left ventricle, the right ventricle, lung, liver, spleen, skeletal muscle, and brain (all p < 0.001). These results indicate that the peptide sequence CSTSMLKAC represents a novel molecular tool that may be useful in targeting ischemic tissue and delivering bioengineered proteins into the injured myocardium by systemic intravenous administration.     

创伤弧菌的药物敏感性

目的创伤弧菌(Vibrio vulnificus)是"人鱼共患病"的重要致病菌,从患"腐皮病"卵形鲳鲹(Trachinotus ovatus)鱼中分离到创伤弧菌TO-3,以阿莫西林等44种药物进行敏感性试验。结果对青霉素类抗菌药物不敏感,对头孢菌素类等抗菌药物很强的耐药性,而对氟哌酸、头孢氯氨苄、氟嗪酸、米诺环素、呋喃妥因、复达欣、萘啶酸、四环素、庆大霉素等抗菌药物高度敏感。在17味中草药中对五倍子、诃子、黄连、石榴皮等中草药极为敏感。     

A successful treatment of Vibrio vulnificus infection

A 65-year-old male patient with a history of alcoholism visited our outpatient clinic complaining of nausea and diarrhea followed by dizziness. Erythema and swelling with partial exfoliation on the right forearm to hand and right thigh were noticed. Vibrio vulnificus was isolated from the purulent discharge of the skin. Due to urgent and intensive treatment of bacterial shock and antimicrobial drugs, the patient fully recovered three months later. We believe that the patient survived from this fatal infection because; 1) the isolates were highly sensitive to a wide variety of antibiotics, 2) the antibiotic therapy was started immediately, with an alternative usage of different antibiotics, and 3) the liver dysfunction of the patient had not been severely damaged by alcohol before the infection.     

创伤弧菌基因组学研究进展

创伤弧菌是人类三大致病弧菌之一,能够通过食源性传播或者伤口感染导致发病,近年来全球发病率逐步升高。随着新一代测序技术的发展,已有上百株创伤弧菌全基因组序列在国际公共数据库公布。这些数据为创伤弧菌基因组学研究提供了重要基础,并促进了对该病原菌遗传多样性、传播和致病机制的认识。本文从基因分型、种群结构和重要毒力因子3个方面对创伤弧菌基因组学研究进展进行归纳总结,以期为创伤弧菌感染、进化和防控研究提供借鉴。