双抗体夹心ELISA检测人C蛋白的研究

本文建立了检测人Ｃ蛋白的双抗夹心ＥＬＩＳＡ方法。该方法的最佳实验条件为：－抗浓度５－８．５μｇ／ｍｌ;二抗密度为１：２００－１：１０００倍稀释。制作了Ｃ蛋白浓度与ＯＤ值的关系的工作曲线,指出了用内插法测定Ｃ蛋白的最佳浓度范围为０－１００ｍｇ／ｍｌ之间。     

Nm23-H1/NDPK-A基因在大肠杆菌中的高效表达及产物纯化的研究

利用聚合酶链反应（ＰＣＲ）技术扩增人二磷酸核苷激酶Ａ亚基（ＮＤＰＫ－Ａ）基因,即ｎｍ２３－Ｈ１／ＮＤＰＫ－Ｋ基因的编码序列,经序列分析后,定向克隆于表达质粒载体ｐＢＶ２２０,在大肠杆菌ＤＨ５α中高效表达出重组人ＮＤＰＫ－Ａ．表达产物为可溶性的非融合蛋白,占菌体总蛋白４２％．斑点ＥＬＩＳＡ法鉴定表明表达产物与ＮＤＰＫ－Ａ标准抗血清呈阳性反应．以ＤＥＡＥ纤维素弱阴离子交换层析、ＣｉｂａｃｒｏｎＢｌｕｅ染料亲和层析结合高效液相排阻色谱技术纯化ｒＮＤＰＫ－Ａ,得纯度为９６．７％的目标蛋白．以反相高效液相色谱法进行酶活性分析,表明纯化的ｒＮＤＰＫ－Ａ能催化ＡＴＰ＋ＵＤＰ＝ＡＤＰ＋ＵＴＰ的反应,比活性为８００Ｕ／ｍｇ蛋白．     

人γ－干扰素生产工艺的研究

采用高密度发酵法发酵重组人γ干扰素产生菌ＳＷＩＮＦ／ＤＨ５α并成功地获得高表达、高产量的菌体,表达的γ干扰素蛋白占菌体总蛋白的６０％以上,２０Ｌ发酵液可收获２ｋｇ（湿重）菌体。纯化过程中采用尿素抽提、稀释、复性、浓缩后通过ＳｅｐｈａｃｒｙｌＳ２００柱的纯化方法,简化了纯化步骤,缩短周期,提高了蛋白回收率。纯化中未采用单抗亲和层析技术,使产品更为安全可靠。最终产品经ＳＤＳＰＡＧＥ检测纯度达１００％,核酸含量和热原均合格,Ａ２８０／Ａ２６０＞１５,比活性达１×１０７ＩＵ／ｍｇ,总回收率达４０％。这说明整个工艺适宜大规模生产的需要,具有实际应用价值。     

一种新的免疫—PCR系统的建立和应用研究

把ＰＣＲ技术作为指示系统引入免疫检测中,建立了免疫－ＰＣＲ技术。在本研究中,以ＰＥＩ作交联剂,首次成功地将特异性抗体直接与ＤＮＡ交联,构建了三种Ａｂ－ＤＮＡ基因探针,组成新的免疫－ＰＣＲ检测系统。此三种特异性Ａｂ－ＮＤＡ探针可用于检测三种相应抗原。检测ＨＳＡ抗原的最低含量可达１０＾－１８ｍｇ／ｍｌ,灵敏度比ＥＬＩＳＡ高１０＾６倍。     

草鱼生长激素非竞争式酶联免疫吸附测定法的建立及鉴定

应用草鱼生长激素（ｇｃＧＨ）单克隆抗体及多价兔抗血清建立了草鱼ＧＨ非竞争式酶’联免疫吸附测定ＥＬＩＳＡ系统。用正辛酸法对腹水单抗进行了分离纯化,获得了高纯度的单抗制备物。聚丙烯酸胺凝胶电泳表明纯化的单抗由分子量分别为５５ｋＤ和２５ｋＤ的两条蛋白带组成。用纯化单抗铺底,用兔抗血清作后续抗体建立了一种测定草鱼ＧＨ的非竞争式双抗夹心ＥＬＩＳＡ方法。交叉试验表明该测定系统只与草鱼ＧＨ和基因重组鲤生长激素（ｒｃＧＨ）具有剂量依存的结合反应,而与大马哈鱼生长激素（ｓＧＨ）、牛生长激素（ｂＧＨ）、大马哈鱼促性腺激素（ｓＧｔＨ）、及黑鲢促性腺激素（ｂｓｃＧｔＨ）等均无交叉反应。该 ＥＬＩＳＡ方法的灵敏度可达０．８ｎｇ／ｍｌ,组内变异系数为 ５．９ ％,组间变异系数为７．６％,回收率达９０％以上。初步应用表明,鲤和团头鲂垂体抽提液、草鱼血清、鲤血清及鲫血清在该测定系统中有剂量依存的反应曲线,而大口鲶、黄颡鱼、中华鲟及黄鳝鱼垂体抽提液及大口鲶、胡子鲶和罗非鱼血清在该测定系统中没有交叉反应。     

大熊猫乳酸脱氢酶同工酶H4的分离纯化和某些性质的研究

采用８－（６－氨己基）－氨基－５－ＡＭＰＳｅｐｈａｒｏｓｅ亲和层分析法和ＤＥＡＥ－Ｓｅｐｈａｒｏｓｅ离子交换层析法从大熊猫心肌中分离纯化出乳酸脱氢酶同工酶Ｈ４,纯化的大熊猫ＬＤＨ－Ｈ４,比活为４４５Ｕ／ｍｇ蛋白,经ＳＤＳ－ＰＡＧＥ,ＡＰＧＥ,等电聚焦电泳鉴定均为一条带,其亚基分了量为３６０００,等电点为５．４５。经测定大熊猫ＬＤＨ－Ｈ亚基Ｎ端被封闭,Ｃ端氨基酸残基经测定为Ｌｅｕ。氨基酸组成分析表明     

酶联免疫分析法测定人α1型基因工程干扰素成品中的干扰素蛋白含量

建立了测定人α１型基因工程干扰素（ｒＩＦＮ－α）成品中干扰素蛋白含量的酶联免疫分析法（ＥＬＩＳＡ）,并用来测定了随机抽样的１０μｇ／支、２０μｇ／支、３０μｇ／支３种规格ｒＩＦＮ－α１成品中的干扰素蛋白含量。证明测定值与推算值一致,偏差小于１０％,而且蛋白含量与生物活性之间呈良好的相关性。本法敏感、特异、快速、简便、灵敏度可达到１ｎｇ／ｍｌ,检测人γ型基因工程干扰素的蛋白含量呈阴性,还能排除保护剂     

大熊猫乳酸脱氢酶同工酶H_4的分离纯化和某些性质的研究

采用８－（６－氨己基）－氨基－５＇－ＡＭＰＳｅｐｈａｒｏｓｅ亲和层析法和ＤＥＡＥ－Ｓｅｐｈａｒｏｓｅ离子交换层析法从大熊猫心肌中分离纯化出了乳酸脱氢酶同工酶Ｈ４．纯化的大熊猫ＬＤＨ－Ｈ４,比活为４４５Ｕ／ｍｇ蛋白,经ＳＤＳ－ＰＡＧＥ,ＰＡＧＥ,等电聚焦电泳鉴定均为一条带,其亚基分子量为３６０００,等电点为５．４５．经测定大熊猫ＬＤＨ－Ｈ亚基Ｎ端被封闭,Ｃ端氨基酸残基经测定为Ｌｅｕ．氨基酸组成分析表明每个亚基含有５个Ｃｙｓ,９个Ｍｅｔ．     

植物组织粗汁液中的番木瓜环斑病毒的ELISA检测技术

本研究建立和改进了检测番木瓜和西葫芦组织粗汁液里的番木瓜环斑病毒（ＰＲＶ）的ＤＡＣ－ＥＬＩＳＡ法和Ｄｏｔ－ＥＬＩＳＡ法。用不同的ＥＬＩＳＡ方法来检测不同寄主植物粗汁液里的ＰＲＶ,其所用的合适的制备粗汁液的缓冲液是不同的。用ＤＡＣ－ＥＬＩＳＡ法检测西葫芦粗汁液时,以０．５ｍｏｌ／Ｌ磷酸盐缓冲液（ｐＨ７．５,内含０．１ｍｏｌ／Ｌ乙二胺四乙酸二钠）为宜;而检测番木瓜粗汁液时,则还要加入０．２５ｍｏｌ／Ｌ脲。用Ｄｏｔ－ＥＬＩＳＡ法检测时,在上述磷酸盐缓冲液中加入２％聚乙烯吡咯烷铜能提高对西葫芦粗汁液的检测效果。应用合适的制备粗汁液的缓冲液,ＤＡＣ－ＥＬＩＳＡ法和Ｄｏｔ－ＥＬＩＳＡ法的灵敏度分别提高到１／４０９６和１／１０２４（稀释度）。本研究还表明,影响ＤＡＣ－ＥＬＩＳＡ法的定过测定的主要因素是粗汁液的稀释度和包被液（０．０５ｍｏｌ／Ｌ碳酸盐缓冲液,ｐＨ９．６）的用过。在较高粗汁液稀释度和包被液的用量相同时,粗汁液里的病毒含量与ＤＡＣ－ＥＬＩＳＡ法的ＯＤ４９２ｎｍ值呈真实的线性关系。     

乙型肝炎疫苗中游离抗原对免疫效果的影响

将按《生物制品规程》制备除氢氧化铝吸附方式不同外,其余所有过程均一致的疫苗各１０批,在ＨＢｓＡｇ含量相同前提下,于５００公升大罐内吸附制备的疫苗中游离抗原含量比在１０公升瓶内吸附制备的疫苗高４倍,两者均数分别为３０４．１ｎｇ／ｍｌ和７３．１ｎｇ／ｍｌ,吸附率分别为９７．９５％和９９．５１％;用ＲＰＨＡ测定游离抗原滴度前者也比后者高２倍;动物免疫效价（ＥＤ５０）高４７％。在上述吸附率范围内,游离抗原含量与ＥＤ５０呈正相关（ｒ＝０．７１７９Ｐ＜０．００１）。     

Time-resolved fluoroimmunoassay of potato virus M with monoclonal antibodies

Mouse monoclonal antibodies (MAbs) specific for potato virus M (PVM) were prepared and the properties of three of them were studied. MAb M4C1 is IgG2b, it binds with high affinity to PVM coat protein, to purified virus preparations and recognises PVM in infected potato leaves and tubers. MAb M6D5 is IgG2a and also reacts with PVM coat protein, purified PVM and with PVM in potato leaf and tuber extracts. In double-antibody sandwich ELISA (DAS ELISA) MAbs M4C1 and M6D5 reacted with all 17 PVM isolates tested. MAb M7 is IgG2b and recognises PVM only in indirect dot ELISA on nitrocellulose filters and viral coat protein on Western blots. MAbs against PVM were used as capture antibodies and europium-labelled MAbs as conjugates in time-resolved fluoroimmunoassay (EuTRFIA). The standard EuTRFIA curve of PVM detection is approximately linear over a range of PVM concentrations from 0.5 ng/ml to 1000 ng/ml. The lowest PVM concentration detectable in EuTRFIA was 0.5 ng/ml and correspondingly 6 ng/ml in DAS ELISA. The use of the europium chelate label allows PVM detection in potato leaf and tuber sap at dilutions greater than 10^--⁴ with very low background fluorescence. EuTRFIA with MAbs, with either one or two incubations is about 10–20 times more sensitive for PVM detection than is DAS ELISA. PVM and PVX, mixed with healthy potato tuber sap, were simultaneously tested in a single sample at concentrations lower than 10 ng/ml by double-label TRFIA using europium-labelled MAbs to PVM and samarium-labelled MAbs to PVX.     

Protein engineering of streptavidin for in vivo assembly of streptavidin beads

Escherichia coli was engineered to intracellularly manufacture streptavidin beads. Variants of streptavidin (monomeric, core and mature full length streptavidin) were C-terminally fused to PhaC, the polyester granule forming enzyme of Cupriavidus necator. All streptavidin fusion proteins mediated formation of the respective granules in E. coli and were overproduced at the granule surface. The monomeric streptavidin showed biotin binding (0.7 ng biotin/microg bead protein) only when fused as single-chain dimer. Core streptavidin and the corresponding single-chain dimer mediated a biotin binding of about 3.9 and 1.5 ng biotin/mug bead protein, respectively. However, biotin binding of about 61 ng biotin/mug bead protein with an equilibrium dissociation constant (KD) of about 4 x 10(-8)M was obtained when mature full length streptavidin was used. Beads displaying mature full length streptavidin were characterized in detail using ELISA, competitive ELISA and FACS. Immobilisation of biotinylated enzymes or antibodies to the beads as well as the purification of biotinylated DNA was used to demonstrate the applicability of these novel streptavidin beads. This study proposes a novel method for the cheap and efficient one-step production of versatile streptavidin beads by using engineered E. coli as cell factory.     

Sandwich ELISAs for quantification of Xenopus laevis vitellogenin and albumin and their application to measurement of estradiol-17 beta effects on whole animals and primary-cultured hepatocytes

Sandwich enzyme-linked immunosorbent assay (ELISA) was developed for quantification of vitellogenin (VTG) and albumin (ALB) in Xenopus laevis. Working ranges of the ELISAs were 2-1000 ng/ml for VTG and 1-300 ng/ml for ALB. Recoveries of plasma VTG by ELISA were over 90% in dilutions of more than 200 times. The VTG-inducing activity of estradiol-17beta (E2) was measured in whole animals and primary cultured hepatocytes. Immersion of mature male animals in more than 1 nM E2 induced a detectable amount of plasma VTG. VTG induction in younger animals was less potent than in the mature animals but the youngest animals (1.5-3 g body mass) was applicable to the exposure test, irrespective of sex. In vitro exposure of hepatocytes to more than 0.1 nM E2 dose-dependently induced secretion of VTG into the culture medium, while ALB secretion was not significantly affected by E2 treatment. When the VTG-induction levels were normalized by use of a concentration ratio of VTG to ALB, the values obtained from three independent experiments were mutually comparable irrespective of differences in cell density and hepatocyte preparation. Thus, this ratio is thought to be useful for large-scale in vitro screening of estrogenic activities of chemical substances.     

Detection of Escherichia coli in blood using flow cytometry

A rapid method for the detection of Escherichia coli in blood has been developed. The method employs blood cell lysis, staining of bacteria with ethidium bromide, and detection of stained bacteria using flow cytometry. The detection protocol requires less than 2 h sample handling time and is not dependent on bacterial growth. This method has been applied to human donor blood specimens seeded with various E. coli concentrations and to two rabbit model systems. Bacterial detection is evident from the in vitro human blood studies at levels of 10 E. coli/ml and from in vivo rabbit model studies at less than 100 E. coli/ml.     

重组人色素上皮细胞衍生因子融合蛋白的制备及其抑制新生血管

目的：人色素上皮细胞衍生因子 (pigment epithelium-derived factor, PEDF)是一种有效的新生血管形成抑制因子和神经营养因子。本文通过原核细胞表达人PEDF蛋白,鉴定其抑制新生血管的生物学活性。方法：采用PCR法扩增人PEDFcDNA,将其克隆到pET32a载体中,在大肠杆菌BL21中表达人PEDF蛋白。经SDS-PAGE和Western-blot鉴定后,镍柱亲和层析法变性条件下纯化重组融合蛋白。Bradford法测蛋白浓度,采用鸡胚脲囊膜法测其对新生血管形成的影响。结果：成功构建了pET32a-PEDF表达载体。重组人PEDF蛋白在BL21宿主菌中获得了稳定高效表达,鸡胚脲囊膜实验结果显示在重组蛋白浓度为0.4、0.04 ng/ml时均有对新生血管的显著抑制作用（P<0.01）,而在4 ng/ml时无抑制作用。结论： 成功高效表达及纯化了重组人PEDF蛋白,鉴定其抑制新生血管的生物学活性,并且证实该活性在一定范围内有效,为进一步研究其功能及推广应用奠定了基础。     

Aspects of chloroquine mutagenicity

Using the Ames plate reversion and fluctuation tests, the mutagenic activity of chloroquine was tested in the new tester strains of Salmonella typhimurium, TA97, TA102, and Escherichia coli strains WP2, WP2hcr, WP6 and WP67. The E. coli transconjugants obtained from the mating transfer of R-plasmid(s) in strains TA97 and TA102 respectively to E. coli WP2, i.e. EE97 and EE102, were also tested. Chloroquine reverted strain TA97 from histidine dependence to independence and also reverted E. coli strains EE97 and EE102 from tryptophan dependence to independence. The E. coli strains WP2, WP2hcr; WP6 and WP67 and S. typhimurium TA102 were not affected. S. typhimurium TA97 could be reverted with 250 ng/ml of chloroquine (therapeutic blood level of chloroquine is 300 ng/ml). Reversion generally occurred optimally at the relatively lower concentrations of chloroquine i.e. 25, 50 micrograms/ml than at higher concentrations. From the properties of the reverted tester strains, the results indicated that chloroquine per se mediated frameshift reversion.     

人IL-6 /sIL-6R 结合分子模型的建立及在药物筛选中的应用

目的：建立人IL-6 /sIL-6R 结合的分子模型,用于筛选IL-6 /sIL-6R的抑制剂。方法：将人IL-6基因克隆至原核表达载体pET28a（+）中表达IL-6蛋白,western blot及人IL-6检测试剂盒分析鉴定表达蛋白。同法将人sIL-6R在pET15b载体中表达,纯化并用western blot检测目的蛋白。依据ELISA原理建立IL-6 /sIL-6R 结合的分子模型,并通过改变IL-6、sIL-6R及IL-6 antibody的浓度来优化该模型,用于IL-6 /sIL-6R拮抗药物的筛选。结果：人IL-6可在载体PET28a（+）中高效表达,且经western blot鉴定正确,人IL-6检测试剂盒检测显示具有较高的免疫活性。sIL-6R在PET15b中表达,western blot鉴定正确。通过对IL-6 /sIL-6R结合的分子模型的优化,得到其最佳条件为：IL-6R 1?g/well, IL-6 500ng/well, IL-6 antibody 1?g/well。应用该模型筛选发现有些化合物可显著抑制IL-6与其受体的结合。结论：成功构建IL-6 /sIL-6R结合的分子模型,为高通量筛选IL-6拮抗剂提供平台。     

胰腺癌潜在肿瘤标志物的探索及在胰腺癌中的应用

目的:探索胰腺癌新的潜在标志物,建立夹心法ELISA体系,并初步应用于胰腺癌患者的血清检测。方法:应用基质辅助激光解吸电离飞行时间质谱(MALDI-TOF-MS)技术对胰腺癌患者术前后血清进行分析,提纯分析差异蛋白并命名为DAP44,通过杂交瘤技术制备出抗DAP44单克隆抗体,用HRP标记法标记抗体,间接ELISA法检测抗体滴度,用制备出的抗体对胰腺癌组织和癌旁组织进行组化染色,采用夹心ELISA(DAS-ELISA)法制备抗DAP44检测试剂盒,检测胰腺癌病人和正常人血清DAP44值,比较两者差异。结果:对差异蛋白进行肽段测序和生物信息分析,并融合了3株能稳定分泌抗DAP44单克隆抗体的杂交瘤细胞(2D6H5,1E4D6,5B8H12),3株杂交瘤细胞分泌的抗体效价均在107以上,通过抗体配对筛选确定以2D6H5为包被抗体,1E4D6为酶标抗体时,DAS-ELISA法敏感性最高。两株抗体组化染色结果显示:癌组织DAP44表达量远高于癌旁。DAS-ELISA法标准曲线线性范围在0.78-25 ng/mL,检测下线为0.78 ng/mL,此方法检测到的胰腺癌病人和正常人血清DAP44平均含量分别为19.707±1.464和10.653±2.221,两者之间有统计学差异(P0.001)。结论:DAP44可能作为潜在的胰腺癌肿瘤标志物,建立的抗DAP44 DAS-ELISA法体系能够初步用于胰腺癌的临床诊断和疗效评估指标。