欧蓍草花粉主要过敏原Parj1的重组表达及鉴定

目的:克隆、表达和纯化欧蓍草花粉主要过敏原Par j1。方法:根据Parj1.0102在GenBank中的序列号获得其核苷酸和氨基酸序列,确定开放阅读框,采用DNAstar软件优化密码子,合成全基因,并克隆到表达载体pET-44a中,转化表达宿主大肠杆菌Rosetta,优化蛋白表达条件并进行亲和层析纯化和Western blot鉴定。结果:PCR扩增及重组质粒测序结果表明成功地构建了pET-44a+/Par j1.0102原核表达质粒。对表达菌表达条件进行优化,最终确定在30℃,IPTG浓度为1.0 mmol/L,诱导4小时时蛋白表达量最高,重组蛋白经亲和层析纯化,SDS-PAGE分析纯化产物在23 kD处有明显的条带。Western blot表明重组蛋白具有与StrepII标签抗体结合活性。结论:国内首次获得融合StrepII标签的Par j1.0102重组蛋白,为欧蓍草花粉过敏诊断及特异性免疫治疗奠定基础。     

椰子花粉过敏原基因的克隆表达、纯化及免疫学鉴定

目的:克隆并表达椰子花粉中泛变应原肌动蛋白抑制蛋白(Profilin).方法:利用RT-PCR结合RACE技术克隆椰子花粉中泛变应原profilin的全长基因,并进行序列分析.然后设计带有酶切位点的特异性引物,采用RT-PCR获得整个椰子花粉profilin的开放阅读框,将其与pET28a载体连接并转化大肠杆菌BL21(DE3)进行诱导表达,通过Ni2+亲和层析柱对重组蛋白进行纯化,采用Western blot检测其IgE结合活性.结果:克隆获得了椰子花粉profilin的全长基因,由608个碱基组成,开放阅读框为396个碱基(包括终止密码子),编码131个氨基酸.经分析,这个序列编码的蛋白为小分子量酸性蛋白,等电点为4.61,分子量约为14 kD.此序列已被GeneBank收录,登陆号为EF173598.重组椰子花粉profilin在大肠杆菌中高效的表达和纯化后,经Western blot检测具有良好的免疫学活性.结论:成功地克隆和表达了椰子花粉profilin,为该花粉profilin用于椰子花粉过敏诊断和免疫治疗提供了理论依据.     

蛔虫过敏原ABA-1融合基因在大肠杆菌中的表达及鉴定

背景：利用蛔虫基因融合技术,可将过敏原ABA-1的主要基因进行融合。 目的：利用大肠杆菌表达系统重组表达蛔虫主要过敏原ABA-1融合蛋白。 方法：从Gene Bank和Protein Database中获取蛔虫主要过敏原ABA-1基因和蛋白序列,选定其中的ABA-1B1,ABA-1A2与ABA-1A1基因重组为融合基因BAA,经密码子优化后,全基因合成目的基因BAA并构建于表达载体PET-44a上,经KCM法转化入大肠杆菌JM109中进行克隆,PET-44a/BAA经NdeⅠ和PstⅠ双酶切及DNA测序正确后,转化入大肠杆菌RosettaBlueTM中,经IPTG诱导表达。表达蛋白经Ni柱亲和层析纯化后,通过Western blot和氨基酸测序鉴定目的蛋白。 结果与结论：大肠杆菌的融合蛋白BAA表达量约占总蛋白的40%,纯化后蛋其白纯度可达90%左右。Western Blot结果显示在相对分子质量45 000处可见一特异目的条带,氨基酸测序显示N端15个氨基酸与目的蛋白完全相同。结果证实,融合蛋白BAA在大肠杆菌中得到高效的表达。     

平榛主要过敏原一个片段区基因的克隆表达及免疫鉴定

目的:克隆表达平榛(Corh)主要过敏原Corh1的一个片段区基因,并纯化表达的蛋白及检测其免疫学活性。方法:采用生物信息学方法选取Corh1的主要抗原表位区,设计带有酶切位点的特异性引物,采用RT-PCR方法扩增目的基因,将其导入pMD18-T载体中测序。将测序正确的质粒双酶切,并将获得的片段基因导入pET-32a中表达。通过Ni2+亲和层析柱纯化重组蛋白,采用Westernblot方法检测其IgE结合活性。结果:克隆并获得了Corh1的主要表位区基因,基因开放阅读框为243个碱基,编码81个氨基酸,蛋白相对分子质量(Mr)约为9000。表达的蛋白以可溶性为主,纯化出的蛋白有较好的免疫原性。结论:成功地克隆表达了Corh1的主要表位区基因,蛋白具有良好的免疫学活性。     

重组低过敏原性粉尘螨过敏原的表达及鉴定

目的:重组表达粉尘螨的低过敏原性过敏原,为安全高效的脱敏治疗服务.方法:通过大肠杆菌表达含前肽序列的粉尘螨过敏原ProDer f 1,通过一系列纯化步骤后,基于过敏病例血清采用ELISA方法比较重组过敏原和天然Der f 1的IgE结合活性,以判断其过敏原性强弱.结果:在大肠杆菌高效表达了ProDer f 1并获得了大量纯化蛋白,结合试验结果显示重组ProDer f 1的IgE结合活性显著降低,显示低过敏原性.结论:经过透析及纯化等步骤后得到的重组粉尘螨过敏原ProDer f 1较天然Der f 1的过敏原性低,可应用于易于标准化的安全高效的脱敏治疗制剂.     

王棕花粉过敏原基因的克隆表达、纯化及免疫学鉴定

目的 克隆并表达王棕花粉中泛变应原肌动蛋白抑制蛋白(profilin).方法 利用RT-PCR结合RACE技术克隆王棕花粉中泛变应原profilin的全长基因,并进行序列分析.然后设计带有酶切位点的特异性引物,采用RT-PCR获得整个王棕花粉profilin的开放阅读框,将其与pET28a载体连接并转化大肠杆菌BL21(DE3)进行诱导表达,通过Ni2+亲和层析柱对重组蛋白进行纯化,采用Western blot检测其IgE结合活性.结果 克隆获得了王棕花粉profilin的全长基因,由675个碱基组成,开放阅读框为396个碱基(包括终止密码子),编码131个氨基酸.经分析,这个序列编码的蛋白为小分子质量酸性蛋白,等电点为4.86,相对分子质量(Mr)约为14.2×103.此序列已被GenBank收录,登录号为EF173599.重组王棕花粉profilin在大肠杆菌中高效表达,进一步经Ni2+亲和层析柱纯化后经Western blot检测具有良好的免疫学活性.结论 成功克隆和表达了王棕花粉profilin,为王棕过敏的诊断和免疫治疗奠定了基础.     

重阳木花粉相关变应原profilin基因的克隆、表达及免疫学鉴定

克隆、表达和纯化重阳木花粉相关变应原profilin基因,并对其免疫学活性进行鉴定。采用RT-PCR和3-’RACE技术获得整个profilin基因的开放阅读框,将其与PET28a载体连接并转化大肠杆菌E.cdiBL21(DE3)进行诱导表达,通过Ni2+亲和层析柱对重组蛋白进行纯化,采用Western blot检测其IgE结合活性。克隆获得了profilin的全长基因,开放阅读框为396个碱基(包括终止密码子),编码131个氨基酸。成功地构建了原核表达载体,并在大肠杆菌中大量地表达了profi-lin,纯化后的重组蛋白进行免疫印迹,结果显示重阳木花粉过敏患者血清对重组profilin反应呈阳性。     

短穗鱼尾葵花粉泛过敏原profilin基因的克隆表达、纯化及免疫学鉴定

目的克隆并表达短穗鱼尾葵花粉中泛变应原肌动蛋白抑制蛋白（profilin）。方法利用RT-PCR结合RACE技术克隆短穗鱼尾葵花粉中泛变应原profilin的全长基因,并进行序列分析。然后设计带有酶切位点的特异性引物,采用RT-PCR获得整个短穗鱼尾葵花粉profilin的开放阅读框,将其与pET28a载体连接并转化大肠杆菌BL21（DE3）进行诱导表达,通过Ni2＋亲和层析柱对重组蛋白进行纯化,采用Western-blot检测其IgE结合活性。结果克隆获得了短穗鱼尾葵花粉profilin的全长基因,由608个碱基组成,开放阅读框为396个碱基（包括终止密码子）,编码131个氨基酸。该序列编码的蛋白为小分子量酸性蛋白,等电点为4.52,相对分子质量约为14200。此序列已被GenBank收录,登陆号为EF173600。重组短穗鱼尾葵花粉profilin在大肠杆菌中高效的表达,进一步经Ni2＋亲和层析柱纯化后经Western-blot检测具有良好的免疫学活性。结论成功地克隆和表达了短穗鱼尾葵花粉profilin,为短穗鱼尾葵花粉过敏的诊断和免疫治疗奠定了基础。     

鸡蛋主要过敏原Gal d1片段基因的克隆、表达、纯化及免疫学鉴定

目的克隆、表达和纯化鸡蛋主要过敏原Gald1区基因,并对其免疫学活性进行鉴定。方法用生物信息学方法对鸡蛋主要过敏原Gald1基因进行抗原表位预测,设计特异性引物,用PCR的方法分别扩增Gald1N端和C端基因,将其分别连接到原核表达载体PET32a上。重组质粒转入大肠杆菌,用IPTG诱导表达,通过镍亲和柱层析法纯化重组蛋白,最后用Western-blotting检测重组蛋白的免疫原性。结果表达的蛋白均以可溶性为主,N端融合蛋白相对分子质量为28600,C端融合蛋白相对分子质量为26800,纯化的N端和C端蛋白均有较好的免疫原性,C端的免疫原性强于N端。结论成功地克隆和表达了鸡蛋主要变应原基因Gald1的N端和C端,为鸡蛋过敏的诊断和免疫治疗奠定了基础。     

青蒿花粉变应原Art a1基因的克隆、表达及特性鉴定

目的克隆、表达和鉴定青蒿花粉变应原Arta1。方法在成功构建青蒿花粉cDNA文库的基础上,用蒿属花粉过敏患者的阳性混合血清进行免疫学筛选,所获阳性克隆亚克隆入pET24a(+),经IPTG诱导表达后,通过Ni2+亲和层析柱对重组变应原进行纯化,并采用Westernblot和ELISA检测其IgE结合活性。结果选用阳性血清从青蒿花粉cDNA文库中筛选到1个阳性克隆,经序列测定,该基因与GenBank中已知基因无明显同源性,含有长度为609bp的开放阅读框,编码203个氨基酸,命名为Arta1;该重组变应原在大肠杆菌中高效表达为相对分子质量(Mr)为22.7×103蛋白,进一步在Ni2+亲和层析柱得到高度纯化;免疫学分析表明重组变应原有良好的IgE结合活性。结论本研究克隆和鉴定了一个青蒿花粉主要变应原Arta1(登录号为:CK700713),为花粉过敏性疾病的诊断和免疫治疗及进一步的实验研究奠定基础。     

Purification and characterization of Pla a 1, a major allergen from Platanus acerifolia pollen

BACKGROUND: Plane trees, as Platanus acerifolia, are an important source of airborne allergens in cities of the United States and Western Europe. Little is known about the relevant allergens of this pollen. The aim of this study was to identify relevant allergens from P. acerifolia pollen and purify and characterize a major allergen of 18 kDa. METHODS: P. acerifolia pollen extract was fractionated using ion exchange, gel filtration, and reverse-phase chromatography. Analyzes were carried out by EAST, SDS-PAGE, isoelectric focusing, immunoblotting and amino-acid sequencing. RESULTS: An 18-kDa protein from the P. acerifolia pollen extract, which we named Pla a 1, was purified. This nonglycosylated protein had an isoelectric point value higher than 9.3 and was recognized by up to 92% of monosensitized Platanus allergic patients and 83% of polyzensitized patients. Sequencing of its N-terminal yielded an amino acid sequence which showed no homology to the known proteins in the databases. Other relevant allergens detected in monosensitized patients were proteins of 43 and 52 kDa, with immunoglobulin (Ig)E-binding prevalences of 83 and 42%, respectively. Profilin was an important allergen in polyzensitized patients. CONCLUSIONS: The most relevant allergens from the P. acerifolia pollen have been determined. A major allergen, specific of this pollen, and named Pla a 1, has been purified and characterized.     

Development of a sandwich-type ELISA for measuring Pla a 1, the major allergen of Platanus acerifolia pollen

BACKGROUND: Platanus acerifolia is an important cause of pollinosis in Western European cities. Pla a 1, a nonglycosylated 18-kDa protein with a prevalence of 80%, is a major allergen in P. acerifolia pollen extracts. Our aim was to develop a Pla a 1-specific ELISA to quantify this protein in allergenic extracts and preparations for clinical use. METHODS: Pla a 1 was purified by cation exchange at pH 7.0, gel filtration, and anion exchange chromatography at pH 10.0. Monoclonal (mAb) and polyclonal antibodies were obtained by immunizing mice and rabbits with nPla a 1. One (5C1) of the 13 mAb obtained was used as capture antibody at 5 mug/ml and biotin-labeled specific polyclonal antiserum at 0.63 microg/ml served for detection. RESULTS: The prevalence of Pla a 1-specific IgE to purified Pla a 1 among 47 P. acerifolia-allergic patients was 79%. The Pla a 1-ELISA developed has a linear range of 3-25 ng/ml, high sensitivity with a detection limit of 0.5 ng/ml and is highly specific as none of the 24 pollen, mite, mold, and plant food extracts tested gave positive results. The assay could quantify Pla a 1-like proteins in other planetree pollen extracts. A good correlation was obtained between Pla a 1 content of 11 P. acerifolia pollen extracts (average content 0.69% of the total protein) and their IgE-binding activity. CONCLUSIONS: The described two-site sandwich ELISA to measure Pla a 1 is useful for standardization of planetree pollen extracts intended for clinical use.     

氯霉素乙酰基转移酶融合蛋白表达、纯化和鉴定

目的对氯霉素乙酰基转移酶(Chloramphenicol acetyltransferase,CAT)基因进行表达和纯化.方法通过PCR扩增编码CAT氨基酸序列的基因片断,并将之克隆入pGEX-2T载体.IPTG诱导蛋白融合表达,产物经琼脂糖亲和层析树脂纯化.免疫印迹鉴定纯化蛋白的抗原性.结果筛选得到的重组子诱导后表达相对分子质量约为52 600的CAT融合蛋白.树脂纯化及酶切后均得到高纯度的蛋白样品.纯化蛋白能与抗CAT抗体特异结合.结论本研究获得了CAT基因的融合表达蛋白,并对其完成纯化,为制备抗血清和抗体打下基础.     

Platanus pollen allergen,Pla a 1: quantification in the atmosphere and influence on a sensitizing population

Background The allergic response in susceptible patients does not always coincide with the presence and magnitude of airborne pollen counts. The prevalence of allergy to Platanus is currently moderate, although the percentage of monosensitized patients is low. This hinders accurate interpretation of the relationship between the amount of pollen inhaled and the patient's symptoms. Objective This study aims to investigate the relationship between the atmospheric concentration pattern of Pla a 1 aeroallergen and the Platanus pollen. Methods The pollen sampling was carried out using a Hirst‐type volumetric trap (Burkard^©) for pollen grains and a Burkard Cyclone sampler (Burkard^©) for Pla a 1 allergen. Serum‐specific IgE levels to Acer sp., Artemisia vulgaris, Betula alba, Chenopodium album, Cupressus arizonica, Cynodon dactylon, Fraxinus excelsior, Lolium perenne, Pinus sp., Plantago lanceolata, Platanus acerifolia, Populus sp., Quercus ilex and Taraxacum officinale allergens were determined using the EAST System (Hytec specific IgE EIA kit; Hycor Biomedical, Kassel, Germany). Results The aerobiological dynamics of Platanus pollen grains and Pla a 1 differed considerably, particularly during the Platanus pollination period. Of the 118 subjects tested, sera from 34 contained specific IgE to Platanus pollen and all of them had specific IgE to other pollen types. Conclusions The presence of the aeroallergen Pla a 1 in the atmosphere appears to be independent of Platanus pollen counts over the same period, which may be contributing to allergic symptoms and sensitization. The number of polysensitized patients displaying allergy to Platanus suggested that allergic symptoms were caused by co‐sensitization or cross‐reactivity involving a number of allergenic particles. Cite this as: D. Fernández‐González, Z. González‐Parrado, A. M. Vega‐Maray, R. M. Valencia‐Barrera, B. Camazón‐Izquierdo, P. De Nuntiis and P. Mandrioli, Clinical & Experimental Allergy, 2010 (40) 1701–1708.     

Studies on the carbohydrate moiety of Pla l 1 allergen. Identification of a major N-glycan and significance for the immunoglobulin E-binding activity

BACKGROUND: Pla l 1, the major allergen of Plantago lanceolata pollen, is a glycoprotein that contains an N-glycosylation site. Carbohydrate moieties of many allergenic glycoproteins have been reported to be IgE-binding determinants responsible for cross-reactivity among different species. OBJECTIVE: To identify the kind of linkages and the type of glycans present in Pla l 1 and to investigate their contribution to the allergic response to this allergen. METHODS: Pla l 1 was deglycosylated by N-glycosidase A and the IgE-binding ability of the unglycosylated protein was evaluated by dot-blot. Identification of beta1 --> 2 xylose and/or alpha1 --> 3 fucose residues in Pla l 1 N-glycan was carried out by incubation with specific antibodies from rabbit antiserum against HRP (anti-HRP). The contribution of this N-glycan to total IgE reactivity was analysed quantitatively by pre-incubation of Pla l 1 with anti-HRP prior to incubation with sera. The role of the carbohydrate moiety of Pla l 1 in cross-reactivity was studied by RAST using unrelated glycoproteins with known sugar composition and structure. RESULTS: The effectiveness of N-glycosidase A to deglycosylate Pla l 1 and the ineffectiveness of the treatment with PNGase F indicate that Pla l 1 carries a complex N-glycan with an alpha1 --> 3 fucose residue in its structure. Furthermore, the presence of beta1 --> 2 xylose and/or alpha1 --> 3 fucose residues was identified in this N-glycan by means of an ELISA. Pre-incubation of Pla l 1 with an anti-HRP antibody caused a weak but significant reduction in IgE reactivity. Some sera from P. lanceolata-allergic patients reacted positively with four glycoproteins that bear N-glycans of complex type but not with fetuine. CONCLUSIONS: Pla l 1 is a glycoprotein that carries at least a complex, major N-linked glycan, with a alpha1 --> 3 fucose residue in its structure and probably also a beta1 --> 2 xylose. This glycan moiety does not seem to constitute a relevant allergenic epitope of Pla l 1.     

沙眼衣原体主要外膜蛋白T、B细胞多表位基因的表达及其鉴定

目的 对沙眼衣原体（Ct）主要外膜蛋白（MOMP）细胞毒性T淋巴细胞（CTL）表位进行预测和选择，并进行Ct MOMP多表位基因克隆和多表位蛋白的原核表达及其抗原性分析，为研制多表位Ct疫苗提供基础资料。方法利用SYFPEITHI法和多项式方案结合预测HLA-A2限制性的0MOMP的CTL表位，选取含多个CTL表位的基因片段作为目的基因，兼顾目的基因上下游存在的TH和B细胞表位的基因，共同组成含CTL、TH和B细胞表位的多表位基因。多表位基因经密码子优化后进行全序列合成，克隆入原核表达载体pET-32a（＋），经IPTG诱导在大肠杆菌BL21（DE3）表达并纯化，经SDS-PAGE和Western blot分析鉴定表达产物。结果 经预测筛选得到了多个MOMPHLA-A2限制性的CTL表位，成功克隆了含CTL、TH、B表位的MOMP多表位基因，并在大肠杆菌中获得了高效表达。表达产物的相对分子质量（Mr）约24×10^3，与预期肘，相符，并用Western blot方法初步证实多表位蛋白有抗原特异性。结论 成功设计了Ct MOMP的T、B细胞多表位基因，并证实在原核表达系统中获得正确表达的多表位蛋白具有良好的抗原性。     

猫过敏原白蛋白的克隆表达、纯化和免疫学特性鉴定

目的 克隆、表达猫过敏原白蛋白(Fel d 2),并分析其过敏原活性.方法 提取猫肝脏总RNA,逆转录合成cDNA,采用适宜引物进行PCR扩增目的 基因,随后将其克隆到原核表达载体PET24a( ),在大肠杆菌中进行表达,镍亲和柱层析法提纯重组蛋白,Western blot检测其过敏原活性.结果 序列分析表明所克隆白蛋白的序列由1 752 bp组成,编码584个氨基酸,与Genebank上的基因序列(NM 001009961)同源性为99.9%.SDS-PAGE显示表达的重组白蛋白Mr65 000.免疫印迹表明重组白蛋白具有与猫过敏原过敏病人血清IgE结合活性.结论 表达的重组白蛋白具有与猫过敏患者血清IgE结合活性.