An enzyme‐linked immunosorbent assay to detect the presence of paralytic shellfish poison using an induced crab protein marker

A purified, high molecular weight protein (referred to as saxitoxin‐induced protein, SIP), was obtained from crabs, Hemigrapsus oregonesis, by affinity chromatography prior to use in a homologous crab SIP enzyme‐linked immunosorbent assay (ELISA) procedure. The SIP measured in H. oregonesis control crabs given acute saxitoxin (SAX) challenge injections (SAX range 0–50 ng), was less than the amount of SIP present in H. oregonesis crabs exposed to a natural toxic dinoflagellate outbreak. The latter were collected from a paralytic shellfish poison (PSP) contaminated coastal area which also contained PSP toxic butterclams (2000 μg PSP per 100 g shellfish), tested by the conventional mouse lethality bioassay procedure. These ELISA results were confirmed by an immunoblotting procedure using anti‐SIP antibody. An immunoblotting procedure of purified SIP and crude SIP antiserum revealed no cross‐reactivity with control, SAX uninjected crabs, thereby indicating specificity of the assay. The method is fast and useful for the screening of antigens expressed in crabs as a consequence of PSP, and represents a procedure that will complement the standard mouse bioassay.     

Use of the enzyme-linked immunosorbent assay for measurement of allergen-specific antibodies

A sensitive and specific enzyme-linked immunosorbent assay (ELISA) for allergen-specific IgG antibodies is described. Various solid-phase supports (microtiter plates), coating procedures, binding kinetics, and presentation of allergen in the assay were investigated. Using optimal conditions the indirect ELISA, in which the allergen is coated onto the well, was capable of detecting 2.4 ng/ml specific IgG antibodies to bee venom phospholipase A2(PLA2). The sandwich ELISA, in which the allergen was immobilized via specific antibody precoated onto the well, detected 0.24 ng/ml IgG antibodies to PLA2.     

An enzyme-linked immunosorbent assay (ELISA) for detection of Fc alpha receptors on isotype-specific T cells

A sensitive and reproducible enzyme-linked immunosorbent assay (ELISA) has been developed using T cell hybridomas as coating antigen, for detection of Fc receptors for IgA (Fc alpha R). T-T hybridomas were generated from fusions of Fc alpha R+ T cell clones from mouse Peyer's patches with the Fc alpha R- R1.1 T lymphoma cell line. The 2 T-T hybridomas (designated Th HA) used here express Fc alpha R as determined by a rosette method and by ELISA. Th HA cells were cultured under conditions for maximum Fc alpha R expression, were added to individual wells of 96-well EIA plates, and were fixed in situ with glutaraldehyde. Plates were incubated with purified mouse monoclonal IgA, IgM or IgG1 and were developed with beta-galactosidase-coupled goat IgG antibodies specific for mouse heavy chains. Using the ELISA, both Th HA cell lines were shown to express significant levels of Fc alpha R, lower but detectable Fc mu R, and no discernible Fc gamma 1R. Interestingly, the rosette assay only allowed detection of receptors for IgA. When splenic lymphocytes were used, good Fc mu R and less Fc alpha R expression occurred on these cells as determined by ELISA and rosetting; however, no Fc gamma 1R cells were detected by either method. Thus, the ELISA is sensitive and reproducible, and allows an objective measurement of FcR expressed on T cells.     

抗青霉素单克隆抗体的制备及初步应用

目的:制备抗青霉素的单克隆抗体(mAb)并建立双抗体夹心ELISA检测方法,对临床上引起青霉素过敏反应的过敏原青霉噻唑蛋白进行研究。方法:将半抗原青霉素和载体蛋白偶联后免疫BALB/c小鼠,应用杂交瘤技术建立稳定分泌抗青霉素mAb的杂交瘤细胞株。常规制备腹水,用辛酸-硫酸铵法纯化,并对纯化的mAb进行特异性鉴定。通过对不同抗体组合的分析和条件的优化,建立检测过敏原的双抗体夹心ELISA方法。结果:经细胞融合、筛选及克隆化,共获得9株稳定分泌抗青霉素mAb的杂交瘤细胞株,其中5株亲和力较高。建立了双抗体夹心ELISA相对定量检测方法,该方法灵敏度达到870 U/L,平均回收率为107.81%,批内变异系数平均为6.7%,批间变异系数平均为9.3%,可用于A群链球菌制剂中青霉噻唑蛋白的检测。结论:成功地制备了抗青霉素的mAb,并建立了相对定量检测青霉噻唑蛋白的双抗体夹心ELISA法。     

Production of a monoclonal antibody with specificity for deoxynivalenol, 3‐acetyldeoxynivalenol and 15‐acetyldeoxynivalenol

Monoclonal antibodies reactive with deoxynivalenol were generated following the immunization of mice with a deoxynivalenol‐mouse serum albumin conjugate. One of the anti‐deoxynivalenol monoclonal antibodies, designated C6–1, exhibited cross‐reactivity with 3‐acetyldeoxynivalenol and 15‐acetyldeoxynivalenol but not with nivalenol, T‐2 tetraol or scirpentriol. An indirect competitive ELISA based on this monoclonal antibody gave 50% inhibition values of 0–6 μg ml^‐1 for deoxynivalenol, 0–2 μg ml^‐1 for 15‐acetyldeoxynivalenol and 10 μg ml^‐1 for 3‐acetyldeoxynivalenol.     

An enzyme-linked immunosorbent assay (ELISA) for IgG and IgA antibodies to respiratory syncytial virus in low dilutions of secretions of human serum and secretions

An enzyme-linked immunosorbent assay (ELISA) has been developed for titration of IgG and IgA antibodies to respiratory syncytial (RS) virus in low dilutions of human serum, colostrum, and nasopharyngeal secretions. Previously the sensitivity of RS virus ELISA on such specimens has been limited by nonspecific absorption of antibody, particularly IgA, to crude antigen preparations. For IgG antibody estimation in infant sera, this unwanted binding was reduced to workable levels by increasing the serum, salt, and detergent concentration of the diluent. Residual nonspecific binding of IgA in colostra appeared mainly due to antigen lipids or to lipoproteins. This was markedly reduced by partitioning Triton X-100-treated infected cell lysate antigens in Arklone. Using the modified ELISA technique for anti-RS virus IgA, good correlations were found with unfixed cell membrane immunofluorescence (MIF) for colostra (r = 0.81, P less than 0.001) and nasal secretions from adult volunteers. In several samples nonspecific absorption of antibody precluded MIF assay, but did not affect the ELISA. Although there was an overall correlation between ELISA for anti-RS IgG antibody in sera, the complement fixation test (r = 0.75, P less than 0.001), and MIF test (r = 0.82, P less than 0.001), the sensitivity of ELISA for antibody responses in convalescent sera of infants from 3 months to 2 years was poor. Conversely, the sensitivity of ELISA for antibody in the sera of older children and for transplacentally acquired antibody in very young infants was higher than that for the other two tests. ELISA was thus less reliable than either CF or MIF for detecting antibody rises in paired infant sera, particularly where maternally acquired antibody remained in the acute serum. The reasons for this apparent disparity are discussed.     

Waning Antibody Responses in Asymptomatic and Symptomatic SARS-CoV-2 Infection

We investigated the kinetics of severe acute respiratory syndrome coronavirus 2 neutralizing antibodies in 7 asymptomatic persons and 11 patients with pneumonia. The geometric mean titer of neutralizing antibodies declined from 219.4 at 2 months to 143.7 at 5 months after infection, indicating a waning antibody response.     

统计有偿和无偿献血者HBsAg抗—HCV与抗—HIV检测结果及比较

目的：了解有偿和无偿献者HBsAg、抗－HCV、抗-HIV I/II测定结果。方法：均采用酶联吸附试验（ELISA）法。结果：有偿和无偿献血者之HBsAg阳性率分别为2.39％和3.32％,抗－HCV阳性率分别为4.81％和2.89％,抗－HIV I／II结果均为阴性。结论：有偿与无偿献血者之间的HBsAg和抗－HCV阳性率比较均有显著性差异（t值分别为2.8633和2.3638,P＜0.05）。     

日本血吸虫成虫67kDa分子抗原的纯化及其对血吸虫病的诊断和疗效考核

目的 为检测日本血吸虫成虫67kDa分子抗原(SjAWA67)对血吸虫病的诊断及疗效考核价值。方法 通过SDS-PAGE和电渗方法,从日本血吸虫成虫抗原中分离纯化出67kDa分子抗原,并用该抗原包被酶标反应板微孔,进行ELISA检测。结果 SjAWA67的纯度已达到电泳纯和免疫纯,对急、慢性血吸虫病患血清的捡出率分别为100％和95％,与正常人血清、肝吸虫病和肺吸虫病患血清均未出现明显的交叉反应,44例血吸虫病患治疗后3、6和12个月后的阴转率分别达45．5％、75．0％和90,9％。结论 SjAWA67分子抗原具有较好的疗效考核价值和现场应用前景。     

白血病患者巨细胞病毒抗体检测及其临床意义初探

目的初步探讨白血病患者巨细胞病毒(HCMV)感染状况及HCMV抗体检测的应用价值.方法采用ELISA法对75例白血病患者和28名健康人HCMV抗体进行检测.其中有11例M3患者作化疗前后对比检测.结果白血病组HCMV-IgM抗体阳性率为2.7%,健康对照组为0;白血病组HCMV-IgG抗体水平较健康对照组显著(P＜0.01)或非常显著(P＜0.005)增高;如以HCMV-IgG抗体高于8.4IU/ml(约临界值1.1IU/ml的4倍)考虑为HCMV活动性感染,则白血病组阳性率35.7%,较健康对照组3.6%明显升高(P＜0.005),且M3化疗后阳性率有上升趋势.结论HCMV抗体检测有助于白血病患者HCMV感染的临床诊疗.