纳米磁性颗粒标记的免疫层析法定量检测人乙型肝炎表面抗原

目的:应用纳米磁性颗粒标记的免疫层析法,研制可应用于乙肝表面抗原(HBsAg)快速定量检测的层析试纸条。方法:用1-乙基-3-(3-二甲基氨丙基)-碳化二亚胺(EDC)/N-羟基琥珀酰亚胺(NHS)交联的方法标记纳米磁珠,喷膜仪喷点硝酸纤维膜;根据双抗体夹心法原理建立免疫层析试纸条,对HBsAg特异性抗体捕获的磁信号进行检测,并对磁信号检测结果进行统计学分析和评价。结果:建立了HBsAg纳米磁性免疫层析试纸条,最低限度检测为0.1 ng/mL的HBsAg抗原,检测灵敏度达到了同类产品ELISA分析法的标准,且检测时间控制在5 min内;经检测临床血清标本证实,该方法可根据磁信号定量检测乙肝患者血清中HBsAg的浓度。结论:HBsAg纳米磁性免疫层析方法具有简单快速、灵敏度高的特点,可应用于临床血清样本中HBsAg的检测;该方法为体内极微量抗原抗体的快速检测建立了新模式。     

纳米磁性颗粒标记的免疫层析法定量检测人绒毛膜促性腺激素

目的:应用纳米磁性颗粒标记的免疫层析法研制用于早孕检测的快速定量层析试纸条。方法:应用EDC/NHS法标记纳米磁珠、Biodot喷膜仪喷点NC膜、双抗体加心法建立免疫层析试纸条、对磁信号进行检测并与ELISA实验做对比,并对结果进行评价。结果:建立了HCG纳米磁性免疫层析试纸条,检测到底线为1miu/ml的HCG抗原,检测灵敏度达到了同类产品ELISA分析法的标准;用此方法与商品化免疫胶体金试纸条对临床样本进行检测,检测符合率达99%,与ELISA法比较符合率达100%,且检测时间控制在5min以内。结论:该方法简单快速,灵敏度高,不仅可以应用于HCG的检测,同时为体内极微量抗原抗体的快速检测建立了新模式。     

抗心型脂肪酸结合蛋白单克隆抗体制备、鉴定和在侧向免疫层析方法中的应用

目的:制备抗心型脂肪酸结合蛋白(H-FABP)单克隆抗体(mAb),并建立侧向免疫层析方法检测血浆中H-FABP。方法:用H-FABP蛋白免疫纯系Balb/c小鼠,采用杂交瘤技术建立能稳定分泌抗人H-FABP的单克隆杂交瘤细胞株。常规制备腹水,纯化后得到特异性抗H-FABP单克隆抗体,进行效价、特异性、亲和力的鉴定分析,并在ELISA平台进行抗体配对,用所筛选到的抗体对初步建立了检测H-FABP的侧向免疫层析方法。结果:成功获得12株稳定分泌抗体的阳性细胞株,并筛选出能相互配对,并应用于侧向免疫层析平台的抗体3D1和5F4,检测临床样品与对照试剂比较总符合率为100%。结论:筛选能稳定分泌抗体的细胞株,配对抗体应用于侧向免疫层析检测方法中,能快速、特异、灵敏的检测出临床样品中H-FABP,为临床应用快速检测H-FABP指标提供了方法和关键材料。     

微囊藻毒素-LR的定量荧光纳米微球免疫层析检测北大核心CSCD

研制了一种快速、定量荧光免疫层析试纸条,用于检测水体中MC-LR含量。基于竞争法原理,采用荧光免疫层析技术,建立MC-LR免疫层析法,并对该试剂考察其灵敏度、准确度、特异性、稳定性等指标。经过对免疫层析试纸条制备参数的优化,即检测线抗原浓度、微球标记量和结合垫微球浓度的选择,加样15 min后,获得了MC-LR荧光免疫层析法的工作直线,方法灵敏度0.195μg/L,回收率99.4%,变异系数小于10%,与MC-LF交叉反应率低,与市售试剂盒检测结果一致,试剂在37℃稳定保存6 d。本研究研制的荧光免疫层析试剂灵敏、稳定、准确,可快速、定量检测水样中MC-LR含量,操作便捷。     

CA19-9时间分辨荧光免疫层析检测方法的建立

本研究旨在建立一种定量检测血清中CA19-9含量的时间分辨荧光免疫层析检测方法。采用双抗体夹心法与荧光免疫层析技术,以羧基荧光微球和NC膜为载体将CA19-9配对抗体进行标记和包被,制备CA19-9检测试纸条。通过标记、包被抗体量对工艺进行优化,并通过线性范围、最低检出限、精密性等性能指标对CA19-9时间分辨荧光层析检测方法进行评价。最终确定20μL荧光微球的标记抗体量为80μg,检测线包被抗体浓度为1.5 mg/mL时,检测时间为15 min,线性范围为12.5–800 U/mL,最低检出限为6.32 U/mL,批内精密性与批间精密性均小于15%,平均回收率为101%,与罗氏电化学发光检测试剂盒平行检测50份临床样本,两者相关系数为0.980 6。初步建立了定量检测血清中CA19-9的荧光免疫层析检测方法,有较好的临床应用前景。     

微囊藻毒素-LR的定量荧光纳米微球免疫层析检测

研制了一种快速、定量荧光免疫层析试纸条,用于检测水体中MC-LR含量。基于竞争法原理,采用荧光免疫层析技术,建立MC-LR免疫层析法,并对该试剂考察其灵敏度、准确度、特异性、稳定性等指标。经过对免疫层析试纸条制备参数的优化,即检测线抗原浓度、微球标记量和结合垫微球浓度的选择,加样15 min后,获得了MC-LR荧光免疫层析法的工作直线,方法灵敏度0.195μg/L,回收率99.4%,变异系数小于10%,与MC-LF交叉反应率低,与市售试剂盒检测结果一致,试剂在37℃稳定保存6 d。本研究研制的荧光免疫层析试剂灵敏、稳定、准确,可快速、定量检测水样中MC-LR含量,操作便捷。     

基于上转磷光颗粒的AFP免疫层析定量检测

目的：建立了上转磷光免疫层析快速定量检测AFP的方法,用于原发性肝癌的诊断。方法：利用上转磷光标记的双抗夹心免疫层析技术检测血清中AFP的含量。将AFP单克隆抗体分别标记上转磷光颗粒并包被硝酸纤维膜,制成免疫层析检测试纸。评价该试纸的灵敏度、特异性和精密度。并通过临床50例血清样本,探讨上转磷光技术与化学发光检测方法的一致性。结果：该方法能在20min内完成,检测灵敏度达5ng/ml。浓度范围从5-1000ng/ml作标准曲线,呈现较好的线性。通过三组平行实验探讨其精密度,变异系数都在10%以内。应用于其它肿瘤标志物如CEA、CA199、AFU和NSE的检测,无交叉反应。与化学发光相比,决定系数R2=0.9692,一致性较好。结论：该方法简便、快速、廉价,可以实现定量,尤其适合基层门诊和体检现场使用。     

免疫层析试纸条技术及其在转基因检测中的应用

转基因检测是转基因生物安全监管的重要环节。目前需要一种适合于大规模筛查的快速检测转基因成分的方法,以扩大转基因生物安全的监测范围。免疫层析试纸条是一种快速免疫分析技术,是目前常用的快速检测方法之一,具有操作简单、样品量少、检测快速、成本低等优点,已在医学、食品和环境等多个领域广泛应用。介绍了免疫层析试纸条的组成结构、检测原理及免疫标记物,并总结了其在转基因检测方面的研究进展。     

尿微量白蛋白荧光免疫层析定量检测试剂的研制及性能评价

旨在建立一种快速定量检测人尿液中微量白蛋白的荧光免疫层析方法。以羧基荧光微球标记的抗人白蛋白单克隆抗体及羊抗兔Ig G为标记抗体,人白蛋白和兔Ig G分别作为检测线和质控线制备荧光免疫层析试纸条。结果显示,所制备检测试剂的线性范围为5-300 mg/L,检测限为2.3 mg/L,批内和批间变异系数(CV)分别为6.4%-9.3%和6.5%-12.3%,平均回收率为102.3%。试剂与尿液中20种干扰物质无交叉反应,实时稳定性试验表明试剂盒有效期12月。临床样本测试,与Orion Quik Read U-ALB试剂相关性较好(r=0.993,P0.01),Bland-Altman分析表明两种方法的诊断结果具有较好的一致性。所制备的荧光免疫层析检测试剂提供了一种简单、快速、准确的定量检测尿液中微量白蛋白的方法。     

基于IgG检测为模型的玻璃介质定量蛋白质芯片的研制及评价

为研制高通量定量检测的蛋白质芯片,以人血清IgG为研究模型,选择戊二醛基修饰的玻片为载体,蛋白质样品溶解于20%甘油的PBS,由机械手将浓度为0.5g/L人IgG单克隆抗体点样在玻片上,人血清白蛋白为阴性对照,以1%的BSA为封闭液对蛋白质芯片进行封闭,并经相应处理,构建用于定量检测人血清IgG蛋白质芯片.先以不同浓度IgG标准品为待测样品,建立蛋白质芯片方法和ELISA方法的标准曲线,两条标准曲线的R2值分别为0.996和0.994(P<0.01).两种方法的检测人IgG结果有很好的相关性(R2=0.9937,P<0.01),其敏感性均在15.625μg/L.用两种方法分别检测10例人血清IgG,结果显示两种方法的检测的IgG浓度有很好的一致性,以玻片为载体的蛋白质芯片可用于微量生物样品的定量检测.     

A Mechanistic Model of PCR for Accurate Quantification of Quantitative PCR Data

Background

Quantitative PCR (qPCR) is a workhorse laboratory technique for measuring the concentration of a target DNA sequence with high accuracy over a wide dynamic range. The gold standard method for estimating DNA concentrations via qPCR is quantification cycle () standard curve quantification, which requires the time- and labor-intensive construction of a standard curve. In theory, the shape of a qPCR data curve can be used to directly quantify DNA concentration by fitting a model to data; however, current empirical model-based quantification methods are not as reliable as standard curve quantification.

Principal Findings

We have developed a two-parameter mass action kinetic model of PCR (MAK2) that can be fitted to qPCR data in order to quantify target concentration from a single qPCR assay. To compare the accuracy of MAK2-fitting to other qPCR quantification methods, we have applied quantification methods to qPCR dilution series data generated in three independent laboratories using different target sequences. Quantification accuracy was assessed by analyzing the reliability of concentration predictions for targets at known concentrations. Our results indicate that quantification by MAK2-fitting is as reliable as standard curve quantification for a variety of DNA targets and a wide range of concentrations.

Significance

We anticipate that MAK2 quantification will have a profound effect on the way qPCR experiments are designed and analyzed. In particular, MAK2 enables accurate quantification of portable qPCR assays with limited sample throughput, where construction of a standard curve is impractical.     

Relative quantification of serum proteins from pancreatic ductal adenocarcinoma patients by stable isotope dilution liquid chromatography-mass spectrometry

We report an innovative multiplexed liquidchromatography-multiple reaction monitoring/mass spectrometry (LC-MRM/MS)-based assay for rapidly measuring a large number of disease specific protein biomarkers in human serum. Furthermore, this approach uses stable isotope dilution methodology to reliably quantify candidate protein biomarkers. Human serum was diluted using a stable isotope labeled proteome (SILAP) standard prepared from the secretome of pancreatic cell lines, subjected to immunoaffinity removal of the most highly abundant proteins, trypsin digested, and analyzed by LC-MRM/MS. The method was found to be precise, linear, and specific for the relative quantification of 72 proteins when analyte response was normalized to the relevant internal standard (IS) from the SILAP. The method made it possible to determine statistically different concentrations for three proteins (cystatin M, IGF binding protein 7, and villin 2) in control and pancreatic cancer patient samples. This method proves the feasibility of using a SILAP standard in combination with stable isotope dilution LC-MRM/MS analysis of tryptic peptides to compare changes in the concentration of candidate protein biomarkers in human serum.     

Assessment of HER2 Status Using Immunohistochemistry (IHC) and Fluorescence In Situ Hybridization (FISH) Techniques in Mucinous Epithelial Ovarian Cancer: A Comprehensive Comparison between ToGA Biopsy Method and ToGA Surgical Specimen Method

We aimed to compare the assay performance characteristics of HER2 status in mucinous epithelial ovarian cancer (EOC) by ToGA (Trastuzumab for Gastric Cancer) biopsy versus ToGA surgical specimen methods. Forty-nine tissue microarray (TMA) samples of mucinous EOC from Asian women were analyzed by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) tests using ToGA trial HER2 scoring methods. The overall concordance between IHC and FISH by the ToGA surgical specimen method is 97.56% and by the ToGA biopsy specimen method is 97.14%. The agreements of HER2 IHC results under both biopsy and surgical specimen methods were nearly perfect (weighted kappa = 0.845). Additionally, the percentage of Her2 FISH amplification showed increasing trend with increasing HER2 IHC ordinals (negative, equivocal, positive) by both TOGA biopsy (P<0.001) and surgical specimen method (P<0.001). After excluding equivocal cases, the sensitivity (100%), PPV (88.89%) and NPV (100%) of HER2 IHC were unchanged under either surgical specimen method or biopsy method. However, the specificity (96.97%) and accuracy (97.56%) of HER2 IHC was slightly higher under the surgical specimen method than those (specificity 96.30%, accuracy 97.14%) under the biopsy method. Of the total 49 cases, the number (n = 14) of HER2 IHC equivocal results under the ToGA biopsy method was 1.75-fold higher than those (n = 8) under the ToGA surgical specimen method (28.57% vs. 16.32%). Therefore, compared to ToGA surgery specimen method, the ToGA biopsy method caused more equivocal IHC cases to be referred to FISH testing and did not increase the detection rates of Her2 FISH amplification.     

Absolute quantification of proteins by LCMSE: a virtue of parallel MS acquisition

Relative quantification methods have dominated the quantitative proteomics field. There is a need, however, to conduct absolute quantification studies to accurately model and understand the complex molecular biology that results in proteome variability among biological samples. A new method of absolute quantification of proteins is described. This method is based on the discovery of an unexpected relationship between MS signal response and protein concentration: the average MS signal response for the three most intense tryptic peptides per mole of protein is constant within a coefficient of variation of less than +/-10%. Given an internal standard, this relationship is used to calculate a universal signal response factor. The universal signal response factor (counts/mol) was shown to be the same for all proteins tested in this study. A controlled set of six exogenous proteins of varying concentrations was studied in the absence and presence of human serum. The absolute quantity of the standard proteins was determined with a relative error of less than +/-15%. The average MS signal responses of the three most intense peptides from each protein were plotted against their calculated protein concentrations, and this plot resulted in a linear relationship with an R(2) value of 0.9939. The analyses were applied to determine the absolute concentration of 11 common serum proteins, and these concentrations were then compared with known values available in the literature. Additionally within an unfractionated Escherichia coli lysate, a subset of identified proteins known to exist as functional complexes was studied. The calculated absolute quantities were used to accurately determine their stoichiometry.     

The absolute quantification strategy: a general procedure for the quantification of proteins and post-translational modifications

Advances in biological mass spectrometry have resulted in the development of numerous strategies for the large-scale quantification of protein expression levels within cells. These measurements of protein expression are most commonly accomplished through differential incorporation of stable isotopes into cellular proteins. Several variations of the stable isotope quantification method have been demonstrated, differing in isotope composition and incorporation strategy. In general, the majority of these methods establish only relative quantification of expressed proteins. To address this, the absolute quantification (AQUA) strategy was developed for the precise determination of protein expression and post-translational modification levels. The AQUA method relies on the use of a synthetic internal standard peptide that is introduced at a known concentration to cell lysates during digestion. This AQUA peptide precisely mimics a peptide produced during proteolysis of the target protein, except that it is enriched in certain stable isotopes. Analysis of the proteolyzed sample by a selected reaction monitoring (SRM) experiment in a tandem mass spectrometer results in the direct detection and quantification of both the native peptide and isotope labeled AQUA internal standard peptide. As an example, the development and application of a method to measure a tryptic peptide representing the amount of polyubiquitin chain formation through lysine 48 (K48) is presented. The simplicity and sensitivity of the method, coupled with the widespread availability of tandem mass spectrometers, make the AQUA strategy a highly useful procedure for measuring the levels of proteins and post-translational modifications directly from cell lysates.     

液质联用多反应监测法定量目标多肽或蛋白质

为建立优化的血浆内源性多肽提取方法,并且构建目标多肽和蛋白质的质谱定量方 法,本研究考察了超滤法、有机溶剂沉淀法和固相萃取法对血浆内源性多肽的提取效果 ,并通过Tricine-SDS-PAGE对提取效果进行比较.通过液相色谱串联质谱多反应监测 （MRM）分析,建立了多肽标准品ESAT-6定量方法,并将ESAT-6定量建立的液相色谱和质谱条件应用于蛋白质的定量,对多肽和蛋白质MRM定量的标准曲线进行了考 察.Tricine-SDS-PAGE结果表明,乙腈沉淀法是最佳的血浆内源性多肽提取方法,低分子量的多肽可以得到很好的富集,且能有效地去除高分子蛋白质的污染.液相色谱串联 质谱MRM法检测血浆内提取的多肽,标准曲线的线性较好,相关系数为0.999.另外,采 用MRM法对胶内分离的蛋白质进行定量,标准曲线的线性相关系数为0.995.综上所述, 本研究构建了一种简单有效的血浆多肽提取方法,通过液质联用MRM法成功地实现了目标多肽和蛋白质定量测定.该定量方法可以推广应用于复杂样品中的多肽和蛋白质的定 量分析.     

A novel alignment method and multiple filters for exclusion of unqualified peptides to enhance label-free quantification using peptide intensity in LC-MS/MS

Though many software packages have been developed to perform label-free quantification of proteins in complex biological samples using peptide intensities generated by LC-MS/MS, two critical issues are generally ignored in this field: (i) peptides have multiple elution patterns across runs in an experiment, and (ii) many peptides cannot be used for protein quantification. To address these two key issues, we have developed a novel alignment method to enable accurate peptide peak retention time determination and multiple filters to eliminate unqualified peptides for protein quantification. Repeatability and linearity have been tested using six very different samples, i.e., standard peptides, kidney tissue lysates, HT29-MTX cell lysates, depleted human serum, human serum albumin-bound proteins, and standard proteins spiked in kidney tissue lysates. At least 90.8% of the proteins (up to 1,390) had CVs ≤ 30% across 10 technical replicates, and at least 93.6% (up to 2,013) had R(2) ≥ 0.9500 across 7 concentrations. Identical amounts of standard protein spiked in complex biological samples achieved a CV of 8.6% across eight injections of two groups. Further assessment was made by comparing mass spectrometric results to immunodetection, and consistent results were obtained. The new approach has novel and specific features enabling accurate label-free quantification.     

A simple and inexpensive approach to interfacing high-performance liquid chromatography and matrix-assisted laser desorption/ionization-time of flight-mass spectrometry

The ability to obtain the accurate mass of a protein in a complex sample mixture aids in determining its correct in vivo form. This is important when identifying post-translationally modified proteins, protein variants or isoforms. The central technique used to separate proteins, 2-dimensional gel electrophoresis offers excellent separation capabilities but does not provide adequate mass accuracy. In this study, an alternative method, liquid chromatography (LC) coupled with matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF)-MS (LC-MALDI) is described. LC-MALDI-MS was used to separate and determine the mass of proteins and peptides in a complex biological sample (i.e., human pituitary gland homogenate). Peptides and proteins were first separated by capillary chromatography and the eluent mixed post-column with sinapinic acid matrix. The flow was then deposited directly onto a standard MALDI target via a capillary nebulizer. In addition to offering high mass accuracy, this method can be applied to peptide and protein quantification.     

凋亡抑制基因livin与survivin在乳腺癌中的表达差异

目的探讨凋亡抑制基因livin在乳腺癌发生、发展中的作用及其与survivin基因的表达和乳腺癌生物学行为之间的关系。方法采用逆转录聚合酶链反应(RT-PCR)检测44例乳腺癌组织、40例癌旁正常组织及4个乳腺癌细胞系中livinmRNA和survivin mRNA的表达,并用免疫组化(IHC)EnVision法检测上述组织和细胞中livin和survivin蛋白的表达。结果livin mRNA和survivin mRNA在乳腺癌组织中的阳性表达率分别为72.7%(32/44)和61.4%(27/44),在癌旁正常组织中的阳性率分别为7.50%(3/40)和5.00%(2/40),二者在癌组织中的表达均显著高于在正常组织中的表达(P<0.01)。livin和survivin蛋白表达情况与mRNA结果相似(P<0.01)。livin和survivin在乳腺癌组织中的表达无显著相关性(P>0.05)。4个乳腺癌细胞系中均有survivin mRNA和蛋白的表达,而MCF-7及MDA-MB-435细胞系中呈阴性表达。survivin基因在伴有淋巴结转移的乳腺癌组织中的表达明显高于无淋巴结转移的乳腺癌组织(P=0.0047),livin在雌激素受体(ER)阴性或者Her2/neu阳性表达的乳腺癌中的阳性率有升高的趋势,但并无显著性差异(P>0.05)。结论livin和survivin基因在人乳腺癌组织中表达上调,提示其可能在乳腺癌发生、发展中起重要促进作用,sur-vivin和淋巴结转移的密切关系表明它的高表达可能反映患者较差的预后。livin和survivin基因一样可能成为乳腺癌治疗中的一个靶基因。     

Application of the standard addition approach for the quantification of urinary benzene

Urinary benzene is used as biomarker of exposure to evaluate the uptake of this solvent both in non-occupationally exposed population and in benzene-exposed workers. The quantitative determination of benzene in urine is carried out in a three steps procedure: urine collection, sample analysis by head space/solid phase microextraction/gas chromatography/mass spectrometry and analyte quantification. The adopted quantification method influences the initial step, hence the whole procedure. Two quantification approaches were compared as regards precision and accuracy: the calibration curves and the standard addition method. Even if calibration curves obtained by using urine samples from different subjects were always linear, their slopes and intercepts showed noteworthy variations, attributable to the influence of the biological matrix on benzene recovery. The standard addition method showed to be more suitable for compensating matrix effects, and a three-point standard addition protocol was used to quantify benzene in urine samples of 11 benzene-exposed workers (smokers and non-smokers). Urine from occupationally exposed workers was collected before and after work-shift. Besides urinary benzene, the applicability of the method was verified by measuring the urinary concentration of the S-phenylmercapturic acid, a specific benzene metabolite, generally adopted as biomarker in biological monitoring procedures. A similar trend of concentration levels of both analytes measured in urine samples collected before work-shift with respect to the after work-shift ones was found, showing the actual applicability of the standard addition method for biological monitoring purposes.