检测外周血MUC1蛋白双抗体夹心ELISA方法的建立及初步应用

目的为提高外周血MUC1蛋白检测的敏感度,建立了抗MUC1多克隆抗体的夹心ELISA试剂盒,并对其进行了初步测试。方法首先成功构建-表达并纯化了MUC1-GST和MUC1-MBP融和蛋白;通过免疫家兔和大鼠,获得抗MUC1血清,经饱和硫酸铵沉淀、Protein A/G纯化及抗GST和MBP抗体吸收的进一步纯化获得纯的家兔抗人及大鼠抗人MUC1多克隆抗体;通过凝血酶溶解MUC1-GST获得MUC1标准品。经不同的筛选确立了以家兔抗人MUC1抗体作为包被抗体、大鼠抗MUC1抗体作为检测抗体的双抗体夹心试剂盒,敏感度可达到0.2 ng/ml。结果对32例乳腺癌患者和20例健康受试者外周血血清中MUC1蛋白水平的检测结果显示,乳腺癌患者的阳性检出率达到53.1%(17例/32例),而健康对照组检出率为0。结论本研究建立的抗MUC1多克隆抗体双夹心试剂盒有望应用于临床诊断。     

重组人碱性成纤细胞生长因子单克隆抗体的制备、鉴定及初步应用

目的制备重组人碱性成纤维细胞生长因子(recombinant human basic fibroblast growth factor,rhbFGF)单克隆抗体,鉴定其特性,建立双抗体夹心ELISA检测方法。方法以rhbFGF为免疫原,免疫Balb/c小鼠,通过细胞融合技术建立能稳定分泌抗rhbFGF杂交瘤细胞株,制备抗rhbFGF单克隆抗体,采用Ig亚类ELISA试剂盒鉴定抗体亚类,间接ELISA法检测抗体效,Western blot鉴定抗体特异性。HRP标记McAb并建立夹心ELISA检测方法。结果获得2株(分别命名2D3、5F7)可分泌特异性McAb的强阳性细胞株,腹水抗体效价在10-5以上,IgG亚类均为IgG1,轻链为K链。Western blot证明2株McAb特异性良好,双抗体夹心ELISA检测rhbFGF最低检测限达到2 ng/ml。结论成功制备高效价的抗rhbFGF单克隆抗体,建立抗rhbFGF双抗体夹心ELISA定量检测方法。     

A型肉毒毒素双抗夹心ELISA检测方法的建立

目的：建立A型肉毒毒素双抗夹心ELISA检测方法。方法：以高亲和力人源抗体ML01作为捕获抗体，以小鼠腹水诱生法制备的鼠源抗体BAS46为检测抗体，HRP标记的羊抗鼠IgG为二抗，建立A型肉毒毒素双抗夹心ELISA检测方法，并评价其灵敏度、重复性、检测线性范围和加样回收率等。结果：A型肉毒毒素双抗夹心ELISA检测法的灵敏度为2.56 pg/ml，变异系数为3.183%～12.030%，线性范围为0.244～62.500 ng/ml，回收率为90%～110%。结论：成功建立了A型肉毒毒素双抗体夹心ELISA检测方法，该方法快速、有效。     

抗人甲胎蛋白单克隆抗体的制备及双抗体夹心ELISA检测技术的建立

目的制备、筛选多株具有商用价值的可配对的高特异性、高亲和力的抗人甲胎蛋白(hAFP)单克隆抗体,初步建立双抗体夹心ELISA检测方法。方法通过经典的淋巴细胞杂交瘤技术筛选分泌抗hAFP单抗的杂交瘤细胞株;对筛选所得单抗的特性进行鉴定分析;双抗体夹心ELISA法筛选最佳配对抗体;初步建立DAS-ELISA检测方法并检测血样,绘制其标准检测曲线并与进口试剂盒比较。结果共获得12株稳定分泌抗hAFP单抗的杂交瘤细胞株,其中Ab 1~Ab 5 5株单抗的腹水效价均高于600万,Ab 5的效价高达3000万;特异性鉴定结果表明Ab 1~Ab 5均能够特异识别天然hAFP分子,但Ab 5与人血清白蛋白(HSA)存在较强交叉反应;抗体配对实验共筛选出5对(Ab 1/HRP-Ab 2、Ab 1/HRP-Ab 4、Ab 3/HRP-Ab 2、Ab 3/HRP-Ab 4和Ab 4/HRP-Ab 1)能够满足hAFP检测要求且无交叉反应的配对抗体,最终确定Ab 1+Ab 3/HRP-Ab 2和Ab 1+Ab 3/HRP-Ab 4为最佳配对组合;利用最佳配对抗体组合建立标准检测曲线,其线性检测范围为5~250 ng/ml,最低检测限2 ng/ml,检测上限400 ng/ml,优于进口试剂盒的线性范围5~200 ng/ml和最低检测限5 ng/ml;样检结果显示自制试剂盒的阳性血清检测准确率99.2%(119/120例),阴性血清准确率100%(40/40例)。结论筛选获得的4株高亲和力、高特异性抗hAFP单抗均可应用于DAS-ELISA试剂盒的研制,Ab 1和Ab 3适合作为捕获抗体,Ab 2和Ab 4适合作检测抗体;自制试剂盒的线性检测范围和最低检测限均优于进口试剂盒,表明具有商用价值。     

三种检测SARS抗体试剂盒的临床使用效果比较

目的 :对重组双抗原夹心法ELISA、全病毒间接法ELISA和免疫荧光分析法 3种SARS抗体诊断试剂盒进行临床应用效果评价 ,比较不同试剂的使用效果。方法 :使用 3种试剂检测了 2 5 7例临床确诊SARS患者的血清标本 2 79例和其他非SARS患者标本 2 4例、健康体检者血清标本 80份。结果 :临床确诊SARS患者发病 1～ 2 0d的病例中双抗原夹心法ELISA检出率最高 ,间接免疫荧光法与其接近 ,全病毒间接法ELISA检出率最低。在发病 2 0d后 ,三者检出率接近 (94 %左右 ) ,3种方法的符合率在 97%以上。在 10 4例非SARS病例中 ,双抗原夹心法ELISA和免疫荧光法均未见出阳性结果 ,全病毒间接法ELISA检出阳性结果 3例 ,假阳性率 2 .9%。结论 :检测SARS抗体双抗原夹心法ELISA试剂盒、免疫荧光试剂盒具有类似的灵敏度和特异性 ,其灵敏度和特异性高于全病毒间接法ELISA。     

检测IL-8的ELISA间接夹心法的建立

利用抗IL-8的单克隆抗体4C3(包被抗体)和免抗IL-8多克隆抗体(第二抗体)建立了检测IL-8的间接夹心法ELISA,当包被抗体浓度为0.5μg/ml、第二抗体浓度为2μg/ml时,其检测下限可达1ng/ml。初步应用此法在部分感染病人血清中检测到明显高于正常人水平的IL-8。     

抗人Apo B100单克隆抗体的制备及夹心ELISA检测方法的建立

目的:制备抗人载脂蛋白B100(Apo B100)单克隆抗体(mAb),建立人Apo B100双抗体夹心ELISA检测方法。方法:将人Apo B100抗原免疫小鼠,通过细胞融合、筛选后得到杂交瘤细胞株。将细胞株用无血清培养基扩大培养并纯化上清获得抗体,测定抗体亲和力、亚型、特异性及表位,最后建立双抗体夹心ELISA方法。结果:获得4株抗人Apo B100的杂交瘤细胞株(4-1-2、4-2-2、4-3-2、4-6-3),其分泌的抗体不与其他相关蛋白交叉反应,亲和力达到1×109L/mol。用4-3-2和4-6-3建立的双抗体夹心法的检测范围为(1.3～80)ng/mL,灵敏度1.24 ng/mL,批内变异系数均小于10%,批间变异系数均小于15%,回收率在90%以上。结论:成功制备了抗人Apo B100mAb,建立了定量检测人Apo B100的双抗体夹心ELISA方法,为Apo B100检测及疾病的诊断奠定基础。     

重组人源细胞珠蛋白单抗制备及检测方法建立

目的制备重组人源细胞珠蛋白（recombinanthumanCytoglobin,rhCygb）单克隆抗体,并建立检测该蛋白双抗体夹心ELISA法,为下一步研究rhCygb药代动力学做准备。方法用纯化的rhCygb免疫BALB/c小鼠,采用甲基纤维素半固体培养基法获得抗rhCygb的单克隆抗体杂交瘤细胞,间接ELISA法筛选制备单克隆抗体,建立双抗体夹心ELISA法。结果筛选获取了稳定分泌单克隆抗体的杂交瘤细胞株,通过抗原表位相加法实验获得5株表位不同的细胞株,Western-blotting验证能与rhCygb特异性结合,间接ELISA法验证其不与本实验室制备的其它PET28a-BL21蛋白及BL21裂解液发生交叉反应。本方法灵敏度为1.25ng/ml,在浓度为10～1250ng/ml时,线性关系良好,相关性达0.9931,实验内和实验间平均变异系数分别为6.2%和10.92%。结论成功建立了灵敏度好、特异性高的双抗体夹心法,为下一步研究rhCygb药代动力学奠定了基础。     

MUC1/Y胞外段在大肠杆菌中的表达和鉴定

目的：获得MUC1／Y胞外段重组蛋白，研究其生物学功能，为肿瘤治疗提供实验依据。方法：利用RT—PCR从MCF7细胞中获得MUC1／Y胞外段编码基因，将其克隆到原核表达载体pET-32a中，并在BL21（DE3）大肠杆菌中进行表达；以亲和层析法对MUC1／Y重组蛋白进行纯化；利用纯化的MUC1／Y蛋白免疫家兔制备MUC1／Y多克隆抗体，然后对乳腺癌组织进行组化染色。结果：在大肠杆菌BL21（DE3）中成功表达了分子量为30000的Trx—MUC1／Y融合蛋白，经镍亲和层析一步纯化所获得的蛋白质纯度〉90％，用Trx-MUC1／Y融合蛋白免疫家兔获得的抗血清对乳腺癌组织的初步组化检测证明MUC1／Y融合蛋白具有很好的生物学活性。结论：成功表达并纯化了具有生物学活性的MUC1／Y胞外段重组蛋白。     

双抗体夹心ELISA定量检测重组人干扰素α1b方法的建立与评价

目的 建立双抗体夹心ELISA法定量检测重组人干扰素α1b的方法.方法 筛选具有不同抗原结合位点的抗重组人干扰素α1b单克隆抗体,分别作为包被抗体和辣根过氧化酶标记抗体,建立双抗体夹心ELISA法定量检测不同批次重组人干扰素α1b含量,评价该法的检出限、精确度、重复性、特异性.结果 所建立的ELISA最低检出限为10 ng/ml,检测线性范围10～100 ng/ml,R2 =0.992,测定值与实际值偏差＞5％,板间变异系数均小于10％.结论 该方法灵敏度高,特异性强,准确性和重复性好,可用于重组人干扰素α1b成品的定量检测.     

Detection of Circulating Anti-Mucin 1 (MUC1) Antibodies in Breast Tumor Patients by Indirect Enzyme-Linked Immunosorbent Assay Using a Recombinant MUC1 Protein Containing Six Tandem Repeats and Expressed in Escherichia coli

Mucin 1 (MUC1), a tumor-associated antigen, is a transmembrane glycoprotein expressed by normal epithelial cells and overexpressed by carcinomas of epithelial origin. Autoantibodies against MUC1 are often found in circulation, either free or bound to immune complexes, which might contribute to limit tumor outgrowth and dissemination by antibody-dependent cell-mediated cytotoxicity, and were found favorably predictive of survival in early breast cancer patients. There is no commercial enzyme-linked immunosorbent assay (ELISA) kit for detecting the anti-MUC1 antibodies in human serum thus far. To detect circulating anti-MUC1 antibodies, we established an indirect ELISA (I-ELISA) using a recombinant MUC1 protein containing six tandem repeat sequences of MUC1 after the antigenicity and specificity of the protein were confirmed. The I-ELISA had a sensitivity of 91.3% and a specificity of 94.1% when a competitive I-ELISA was used as a reference test. The results showed that more patients with benign breast tumors (P = 0.001) and breast cancer patients before primary treatment (P = 0.010) were found to have anti-MUC1 IgG than healthy women; anti-MUC1 IgG before primary treatment was found more than after primary treatment (P = 0.016) in breast cancer patients. Interestingly, the anti-MUC1 IgG serum level was reversely correlated to that of CA15-3 antigen in advanced-stage patients (r = −0.4294, P = 0.046). Our study has demonstrated the suitability of the established I-ELISA for detecting circulating anti-MUC1 antibodies in human serum. Furthermore, we found that circulating anti-MUC1 antibodies may still bind MUC1 shed into blood in stage IV breast cancer, which can support the use of MUC1-target immune therapy strategies.Mucin 1 (MUC1), also called cancer antigen 15-3 (CA15-3) or polymorphic epithelial mucin, is a transmembrane glycoprotein with variable number tandem repeats (VNTR) of a 20-amino-acid motif as its large extracellular fragment. The repeat units contain potential O glycosylation sites represented by serine and threonine residues, which act as a scaffold for the attachment of O-glycans, resulting in the formation of a highly glycosylated extended repetitive structure (22). CA15-3 is defined as the glycoprotein that binds with two monoclonal antibodies (MAbs): DF3 and 115D8. The DF3 antibody recognizes the VNTR of MUC1 (sequence DTRPAPGS), which corresponds to amino acids Asp-Thr-Arg-Pro-Ala-Pro-Gly-Ser. The 115D8 MAb is the solid-phase capture antibody, which binds to a peptide-carbohydrate epitope on the same repeat (11). As a tumor-associated antigen, MUC1 is overexpressed on various carcinomas of epithelial origin, including breast cancer, pancreatic cancer, ovarian cancer, and multiple myeloma, etc. Because of its deficient glycosylation with exposed VNTR in cancer cells, MUC1 can behave as a self-antigen to stimulate an immune response, which provides evidence for vaccine immunotherapy of targeting MUC1 (6, 19, 29).Free and compound autoantibodies against MUC1 can be detected both in patients with malignant tumors and in healthy people (2, 17, 24). Studies have demonstrated that circulating anti-MUC1 antibodies may be used as a favorable prognostic factor for patients with early breast cancer and pancreatic cancer (7, 25). In addition, previous studies have shown that the antibodies might contribute to limit tumor outgrowth and dissemination by antibody-dependent cellular cytotoxicity (1, 8, 28). It is believed that free anti-MUC1 antibodies can bind MUC1 and form MUC1 circulating immune complexes (MUC1-CIC) in blood circulation (3); however, patients with stage IV of breast cancer present low MUC1-CIC, although more common anti-MUC1 antibodies and MUC1 exist in their sera (4, 26). A contradictory result indicated that anti-MUC1 antibodies in stage IV of breast cancer could not bind or neutralize MUC1 antigen, and they were of low affinity (4).Thus far, there is no commercial enzyme-linked immunosorbent assay (ELISA) kit for detecting the anti-MUC1 antibodies in human serum. Mostly, synthetic MUC1 VNTR peptides were used as coating antigens in ELISA for detecting anti-MUC1 antibodies in human sera (13, 27). Alternatively, recombinant MUC1 VNTR containing peptide was also used as antigen for detecting circulating anti-MUC1 antibodies by Western blotting (9). Although the recombinant MUC1 VNTR containing peptide expressed in Escherichia coli cannot be glycosylated as in eukaryotic cells, it has been demonstrated to be efficient in detecting anti-MUC1 antibody because MUC1 is less or not glycosylated when expressed in tumor cells.In the present study, we constructed a recombinant MUC1 protein, 8R-MUCPT, which contained six MUC1 VNTRs. After the antigenicity and specificity of the 8R-MUCPT were verified, we established an indirect ELISA (I-ELISA) using 8R-MUCPT as a coating antigen to detect anti-MUC1 antibodies in the sera of patients with benign breast tumors and breast cancer. The results have demonstrated the potential of this recombinant MUC1 protein as detecting antigen and the suitability of the established I-ELISA for detecting circulating anti-MUC1 antibodies. In addition, the results suggested that anti-MUC1 antibodies in serum may play a role in neutralizing MUC1 VNTR core peptides and forming MUC1-CIC. By analyzing the relationship between circulating MUC1 and anti-MUC1 antibodies in advanced-stage patients, we were able to deduce the same neutralizing role for the antibodies in stage IV breast cancer.     

Endogenous antibody responses to mucin 1 in a large multiethnic cohort of patients with breast cancer and healthy controls: Role of immunoglobulin and Fcγ receptor genes

High levels of naturally occurring IgG antibodies to mucin 1 (MUC1), a membrane-bound glycoprotein that is overexpressed in patients with breast cancer, are associated with good prognosis. This suggests that endogenous anti-MUC1 antibodies have a protective effect and, through antibody-mediated host immunosurveillance mechanisms, might contribute to a cancer-free state. To test this possibility, we characterized a large number of multiethnic patients with breast cancer and matched controls for IgG antibodies to MUC1. We also aimed to determine whether the magnitude of anti-MUC1 antibody responsiveness was associated with particular immunoglobulin GM (γ marker), KM (κ marker), and Fcγ receptors (FcγR) genotypes. After adjusting for the confounding variables in a multivariate analysis, we found no significant difference in the levels of anti-MUC1 IgG antibodies between patients and cancer-free controls. However, in patients and controls, particular GM, KM, and FcγR genotypes—individually or epistatically—were significantly associated with the levels of anti-MUC1 IgG antibodies in a racially restricted manner. These findings, if confirmed in an independent investigation, could help identify individuals most likely to benefit from a MUC1-based therapeutic or prophylactic vaccine for MUC1-overexpressing malignancies.     

Antigenic differences between metastatic cells in bone marrow and primary tumours and the anti-MUC1 humoral immune response induced in breast cancer patients

The dissemination of a malignant neoplasia is a complex process, which requires a set of molecules that remains unknown. It has been suggested that mucins and their carbohydrate-associated antigens may be implicated in tumour spreading which may be also influenced by an anti-MUC1 immune response. In this pilot study, we report the pattern of carbohydrate and peptidic MUC1-associated epitopes on carcinoma cells isolated from bone marrow (BM), taking into account primary tumour histopathologic features. We also bring information about the anti-MUC1 humoral response in these patients. Seventeen patients with invasive breast carcinoma were included. A sample of the primary tumour, a serum sample and a BM aspirate were obtained from each patient. Clinical features studied were tumour size, number of metastatic nodes, histological type and disease stage. Standard immunohistochemistry was performed with antigenic retrieval using different monoclonal antibodies (MAbs): anti carbohydrate antigens: Lewis x (KM380), sLewis x (KM93), Lewis y (C14) and Tn, anti-MUC1 peptide core MAbs: C595, HMFG2 and SM3, anti-cytokeratins, anti-protoncogenes ErbB2 and ErbB3 (IgG) MAbs and also anti-CD34 and anti-CD45 MAbs. ELISA techniques were employed to study circulating MUC1 as well as free and complexed anti-MUC1 antibodies. Immunohistochemical results showed that carbohydrate antigenic expression increases in BM neoplastic cells compared to the original tumours. However, we were not able to demonstrate that a humoral immune response to MUC1 has been induced in these patients. Finally, the employed procedures allow the selective immortalisation of micrometastatic carcinoma cells since short-term cell lines were established.     

Development of a novel enzyme-linked immunosorbent assay for blood and urinary eosinophil-derived neurotoxin: a preliminary study in patients with bronchial asthma

BACKGROUND: Eosinophil-derived neurotoxin (EDN), also called eosinophil protein X (EPX), has been suggested to be a useful marker of eosinophilic inflammation. However, no commercial enzyme-linked immunosorbent assay (ELISA) kit for EDN is available yet. METHODS: EDN was purified from pooled urine from healthy male volunteers. Polyclonal and monoclonal anti-EDN antibodies were subsequently raised, and a sandwich ELISA for EDN was established. EDN levels in serum, plasma and urine from asymptomatic patients with bronchial asthma were measured by the ELISA method. Some of the blood samples were also measured by a commercial radioimmunoassay (RIA) kit. RESULTS: The ELISA method detected human EDN with a minimum detection limit of less than 0.62 ng/ml and did not cross-react with other eosinophil granule cationic proteins including eosinophil cationic protein. The intra- and interassay coefficients of variation of the ELISA method ranged from 2.6 to 3.6% and from 6.5 to 9.4%, respectively. Good linearity was observed with serially diluted different samples, and the recoveries of the purified EDN added to serum samples ranged from 85 to 110%. Median EDN concentrations in serum (36.9 vs. 19.1 ng/ml), plasma (23.0 vs. 14.5 ng/ml) and urine (118.2 vs. 72.1 microg/mmol Cr) were significantly raised in asymptomatic asthmatic patients compared with healthy control subjects. EDN levels in serum, plasma and urine from the patients significantly correlated with the number of peripheral blood eosinophils, but not total serum IgE levels. A significant relationship between EDN values measured by the EPX-RIA kit and the EDN-ELISA method was observed. CONCLUSIONS: We have developed a novel efficient ELISA method to specifically measure blood and urinary EDN, which may be useful to study the role of eosinophils in allergic diseases including bronchial asthma.     

Enzyme immunoassay of human epidermal growth factor receptor (hEGFR)

Overexpession of EGFR has been reported in a variety of human cancers and serves as a target for diagnosis and therapy. In the case of breast cancer, about 48% EGFR and have poor clinical prognosis. Besides the prognostic factors like tumor size, nodal status, histological grade etc., which are significant in the management of breast cancer, EGFR level might also serve as an additional parameter. Immunocytochemical assay has been extensively used to study the expression of EGFR in various cancers. We have generated a panel of monoclonal antibodies against human EGFR with a view to evaluate their application for the diagnosis and therapy of these cancers. In the present study, an EIA has been developed using 2 monoclonal antibodies against hEGFR designated as CIBCNSH3 as the capture antibody and CIBCRGC1 as the detector antibody. EGFR isolated from MDA MB 468, a human breast carcinoma cell line, with high expression of EGFR and purified by conA affinity chromatography and HPLC has been used to develop the EIA procedure. Sera samples of 150 healthy women donors, of 300 breast cancer patients with different histological types of malignancies and of various other types of cancers have been analyzed. The control women had a range for serum EGFR level of 7-162 fmol/ml, whereas the 300 breast cancer patients studied had a range of 126-1587 fmol/ml with a cut off value of 180 fmol/ml. It is interesting to note that 67.5% of breast cancer patients had elevated levels of circulating EGFR. These results might suggest that serum EGFR level can be used as prognostic marker for breast cancer. The serum EGFR level will be compared with disease free interval and patient survival.     

Quantitation of macrophage migration inhibitory factor (MIF) using the one-step sandwich enzyme immunosorbent assay: elevated serum MIF concentrations in patients with autoimmune diseases and identification of MIF in erythrocytes

We raised monoclonal antibodies against human macrophage migration inhibitory factor (MIF), and developed a one-step sandwich enzyme-linked immunosorbent assay (ELISA) method highly specific for human MIF. The ELISA system utilizes a solid phase monoclonal antibody as a capture antibody and a horseradish peroxidase-conjugated monoclonal antibody as a detector antibody. We used this ELISA method to evaluate the serum level of MIF in 240 healthy volunteers (140 males and 100 females). We found no significant difference in MIF concentration with respect to age. A significant difference was found with respect to sex, with the mean value (+/- SD) for male subjects of 5.3+/-2.3, and that for female subjects of 4.6+/-2.3 ng/ml (p<0.05). We next measured the serum MIF contents of patients with autoimmune diseases, and found that MIF levels were significantly elevated in patients with systemic lupus erythematosus and rheumatoid arthritis, 20.0+/-11.0 ng/ml and 21. 7+/-11.2 ng/ml, respectively. Using anti-MIF antibody-immobilized sepharose column chromatography, we discovered for the first time that MIF was present in erythrocytes. Taken together these results suggest that MIF plays a major role in autoimmune diseases and, moreover, potentially induces various patho-logical outcomes in cases of hemolytic disorders.     

血清可溶性白细胞介素6受体的检测及其临床意义

以夹心ELISA方法检测30名正常对照者,22份可抽提核抗原(ENA)抗体阳性血清及49名Grave病患者血清sIL-6R水平.结果表明;本方法的灵敏度为80pg/ml,批内及批间误差分别为7.5%和9.6%.正常对照组、Grave病缓解组、Grave病未缓解组及ENA抗体阳性组的血活sIL-6R浓度分别为185.55±53.0ng/ml、191.65±62.0ng/ml、241.67±69.0ng/ml和264.86±108.53ng/ml.经统计学处理Grave氏病未缓解组和ENA抗体阳性组sIL-6R水平明显高于正常对照组对,Grave病缓解组与上常对照组血清sIL-6R浓度无差异提示slL-6R检测在ENA抗体产生中的作用和Grave病监测病情中的价值.