Measurement of antigen specific lymphocyte proliferation using 5-bromo-deoxyuridine incorporation An easy and low cost alternative to radioactive thymidine incorporation

The classical in vitro assay for the determination of cell mediated immune responses is the lymphocyte transformation test (LTT) in which cell proliferation is measured by incorporation of radioactive labeled thymidine (³H-TdR). The LTT assay using ³H-TdR is less suited for modestly equipped laboratories as it is costly, laborious and involves the need to handle radioactive isotopes and specialized equipment.

Here we describe an improved alternative LTT method which is capable of detecting specific cellular immune reactions (CMI) against (mycobacterial) antigens in vitro. This assay, the bromodeoxyuridine-ELISA LTT test, is simple, less expensive, reproducible and is as sensitive as the ³H-TdR test. The specific advantages of the test are a simple denaturation step and the fact that no radioactive isotopes are needed. The test is specifically suited for research laboratories in tropical countries which study CMI in those human infectious diseases where this arm of the immune response plays a pivotal role in the generation of immunity, e.g., in tubercolosis, leprosy and leishmaniasis.     

Differential diagnosis of acute viral hepatitis using rapid, fully automated immunoassays

We report the development of three rapid, fully automated immunoassays allowing the differential diagnosis of acute viral hepatitis. These assays detect HBsAg, IgM antibody to hepatitis B core antigen (IgM anti-HBc) and IgM antibody to hepatitis A virus (IgM anti-HAV) using the IMx instrument system. All IMx assays were run in less than 45 minutes and all steps were fully automated including specimen dilution steps. Specimens from blood donors, diagnostic and hospital patients, and individuals with a variety of infectious and immune diseases were tested for IgM anti-HAV (n = 1473) or for IgM anti-HBc (n = 1606) or for HBsAg (n = 9700) by the IMx and commercially available EIA and RIA. Each IMx assay showed 99.8% agreement with current EIA. Reproducibility in all hepatitis IMx assays was significantly better than that observed with manual or semiautomated assays; within-run and between-run % CV ranged from 2.2 to 4.8 and 3.5 to 10.3 respectively. In 29 acute hepatitis B patients studied, HBsAg and IgM anti-HBc were detected in the first available patient bleed collected from 0 to 4 week from the onset of symptoms. IgM anti-HBc persisted at reactive levels in the IMx assay for 1 to 24 weeks (mean 12.1 +/- 5.3 weeks) after the patient presented with symptoms. In individuals exposed to hepatitis A, IgM anti-HAV was detectable by IMx by 40 days post exposure (average 33.5 days) and IgM had declined to unreactive levels in IMx for all patients by from 3 to 6 months post exposure. These data demonstrate the use of these rapid IMx assays for differentiation of acute hepatitis A and B.     

Antigenic properties of ovalbumin following heat denaturation at different temperatures: Comparison with enzymatic Denaturation

Eighteen monoclonal antibodies (MAbs) raised from mice which were immunized with either native ovalbumin (NOA) or ovalbumin which had been heat denatured at 100°C, (HDOA) were used to study antigenic modifications induced by either heat or subtilisin treatment. Using enzyme immunoassays (EIA) we have defined three major groups of antigenic sites: Group I thermolabile native epitopes; Group II relatively thermostable native epitopes; Group III epitopes specific to heat‐denatured ovalbumin. Heatdenatured ovalbumin can be separated into monomers and polymers which constitute 1% and 99% of the molecules respectively. Whereas MAbs belonging to Groups I and II bound to the monomeric form (mHDOA), MAbs belonging to Group III only bound to the polymeric form (pHDOA). Plakalbumin (PK) behaved similarly to pHDOA since it was recognized by many MAbs from Group III and a few from Group II. Nevertheless, PK remained as a monomeric molecule, whereas heat‐denatured ovalbumin existed mainly as polymeric aggregates. The epitopes present on ovalbumin after different heating procedures (time/temperature) were found to be stable after cooling, thus allowing specific recognition by different MAbs. The critical modification of the protein structure was found to take place at 75°C. Two main conclusions can be drawn from these results: (i) heat and enzymatic denaturation of ovalbumin led to similar antigenic modifications—these may be explained by the exposure of hydrophobic residues in both HDOA and PK as evidenced from 8‐anilino‐1‐sulphonic acid fluorescence spectra; (ii) the panel of ovalbumin‐specific MAbs was able to differentiate between the various heat treatments which had been applied to ovalbumin within the range 65–85°C, even after subsequent cooling. The aggregation of ovalbumin molecules during the heating process constitutes the main type of antigenic modification.     

Preimplantation genetic diagnosis for cystic fibrosis: the Montpellier center's 10‐year experience

This study provides an overview of 10 years of experience of preimplantation genetic diagnosis (PGD) for cystic fibrosis (CF) in our center. Owing to the high allelic heterogeneity of CF transmembrane conductance regulator (CFTR) mutations in south of France, we have set up a powerful universal test based on haplotyping eight short tandem repeats (STR) markers together with the major mutation p.Phe508del. Of 142 couples requesting PGD for CF, 76 have been so far enrolled in the genetic work‐up, and 53 had 114 PGD cycles performed. Twenty‐nine cycles were canceled upon in vitro fertilization (IVF) treatment because of hyper‐ or hypostimulation. Of the remaining 85 cycles, a total of 493 embryos were biopsied and a genetic diagnosis was obtained in 463 (93.9%), of which 262 (without or with a single CF‐causing mutation) were transferable. Twenty‐eight clinical pregnancies were established, yielding a pregnancy rate per transfer of 30.8% in the group of seven couples with one member affected with CF, and 38.3% in the group of couples whose both members are carriers of a CF‐causing mutation [including six couples with congenital bilateral absence of the vas deferens (CBAVD)]. So far, 25 children were born free of CF and no misdiagnosis was recorded. Our test is applicable to 98% of couples at risk of transmitting CF.     

Inhibition of adhesion of Clostridium difficile to human intestinal cells after treatment with serum and intestinal fluid isolated from mice immunized with nontoxigenic C. difficile membrane fraction

Diarrhea and pseudomembrane colitis caused by Clostridium difficile infection is a global health concern because of the high recurrence rate after standard antibiotic therapy. Vaccination presents a powerful countermeasure against disease recurrence. In this study, mice vaccinated with the nontoxigenic C. difficile membrane fraction generated a marked immune response to the antigen, as demonstrated by the serum IgG and intestinal fluid IgA levels. Significantly, pretreatment with harvested IgG- and IgA-containing fluids was sufficient to prevent in vitro adhesion of C. difficile to human Caco-2 intestinal cells. These results highlight the potential of nontoxigenic C. difficile membrane fraction as a vaccine candidate for C. difficile infection.     

Sensitivity of a rapid point of care assay for early HIV antibody detection is enhanced by its ability to detect HIV gp41 IgM antibodies

BackgroundAnti-HIV-1 IgM antibody is an important immunoassay target for early HIV antibody detection.ObjectivesThe objective of this study is to determine if the early HIV antibody sensitivity of the 60 s INSTI test is due to detection of anti-HIV-1 IgM in addition to IgG.Study DesignTo demonstrate HIV gp41 IgM antibody capture by the INSTI HIV-1 gp41 recombinant antigen, an HIV-IgM ELISA was conducted with commercial HIV-1 seroconversion samples. To demonstrate that the INSTI dye-labelled Protein A-based colour developer (CD) has affinity to human IgM, commercial preparations of purified human immunoglobulins (IgM, IgD, IgA, IgE, and IgG) were blotted onto nitrocellulose (NC) and probed with the CD to observe spot development. To determine that INSTI is able to detect anti-HIV-1 IgM antibody, early seroconversion samples, were tested for reduced INSTI test spot intensity following IgM removal.ResultsThe gp41-based HIV-IgM ELISA results for 6 early seroconversion samples that were INSTI positive determined that the assay signal was due to anti-HIV-1 IgM antibody capture by the immobilised gp41 antigen. The dye-labelled Protein-A used in the INSTI CD produced distinct spots for purified IgM, IgA, and IgG blotted on the NC membrane. Following IgM removal from 21HIV-1 positive seroconversion samples with known or undetermined anti-HIV-1 IgM levels that were western blot negative or indeterminate, all samples had significantly reduced INSTI test spot intensity.ConclusionsThe INSTI HIV-1/HIV-2 Antibody Test is shown to detect anti-HIV-1 IgM antibodies in early HIV infection which enhances its utility in early HIV diagnosis.     

细胞因子在肺结核病理生理过程及治疗随访中的临床意义

目的 探讨肺结核患者治疗前后血清细胞因子水平变化的临床意义.方法 采用酶联免疫吸附分析(ELISA)测定215例肺结核患者治疗前后和60例正常对照组血清细胞因子IL-2,IL-10,IL-17,IL-18水平,并进行对比性分析,测定了215例肺结核患者治疗后的痰菌转阴率和有效率,通过测定灵敏度、特异度和准确度等指标比较了单项和多项细胞因子在肺结核患者诊断中的变化.结果 215例肺结核患者治疗前血清IL-2和IL-10水平较之60例正常对照组明显降低(tIL-2=3.216,tIL.10=3.164,P均＜0.01),而IL-17和IL-18水平明显增高(tIL-17=2.942,P＜0.01,tIL-18 =2.175,P均＜0.05),治疗后血清IL-2和IL-10水平明显增高(tIL-2=2.237,tIL-1o=2.248,P均＜0.05),而血清IL-17的水平降低(tIL-17 =2.120,P＜0.05),血清IL-18恢复至正常水平(tIL-18=1.873,P＞0.05).215例肺结核治疗后的痰菌转阴率为87.00％,有效率为92.1％.结论 细胞因子参与肺结核的病理生理过程,并是治疗后随访的有价值指标.单项细胞因子测定在肺结核诊断中的价值较低,四项联合测定的灵敏度,特异度和准确度分别为69.8％,65.0％和72.0％.     

神经生长因子在食管鳞癌细胞中的表达及分泌

目的 探讨神经生长因子（NGF)与食管鳞癌细胞分化的相关性。方法 采用有限稀释法分选出圆形和梭形单细胞克隆,采用无血清悬浮培养获得细胞球细胞, 贴壁的Eca109细胞分别在含血清和不含血清培养基中培养48h;分别采用反转录-聚合酶链式反应（RT-PCR)技术和免疫印迹法,检测NGF在食管鳞癌细胞中mRNA水平和蛋白水平的表达;免疫荧光技术检测NGF在食管鳞癌细胞中的表达定位;免疫组织化学法检测食管鳞癌组织中NGF的表达定位;用酶联免疫吸附法（ELISA）检测NGF在Eca109细胞培养基中的分泌情况。结果 在Eca109细胞中能检测到NGF的mRNA水平和蛋白水平的表达,其中NGF在细胞球细胞中的mRNA水平和蛋白水平的表达量最高。食管癌组织中检测到NGF表达于细胞质。Eca109细胞在无血清培养条件下能够分泌NGF,且明显高于含血清培养基中的含量。结论 食管癌细胞系Eca109表达并分泌NGF,并且食管癌组织中表达NGF,NGF可能在维持食管鳞状细胞癌的干细胞特性发挥了重要作用。     

川崎病患儿血管内皮细胞抗体检测临床意义分析

探讨血管内皮细胞抗体（AECA）检测对川崎病（KD）患儿诊断及预后评价。方法　2007年8月至2008年5月在广州市儿童医院住院的5岁以下KD患儿55例,采用以人脐静脉内皮细胞和猴骨骼肌为基质的间接免疫荧光技术检测55例急性期KD患儿和43例对照组（发热对照23例,健康对照20名）血清中AECA,并通过比较AECA阴性和阳性组相应的实验室、临床指标,初步评估AECA对KD早期诊断、预后转归的临床应用价值。 结果　KD患儿中AECA阳性率为40.0%,明显高于健康对照组（5.0%, P = 0.004）,但与发热对照组差异无统计学意义（17.4%,P = 0.053）;AECA对KD诊断的灵敏度为40.0%,特异性为88.4%,阳性预测值与阴性预测值则分别为80.0%、53.5%,准确率为60.4%。抗中性粒细胞浆抗体（ANCA）、蛋白酶3抗体（抗-PR3）阳性KD患儿中AECA阳性率显著高于阴性者（P值分别为0.013、0.034）。AECA阳性组与阴性患儿组临床指标、实验室指标差异无统计学意义。AECA阳性组冠状动脉瘤发生率高于阴性组（P < 0.05）,发生动脉瘤的相对危险度为6.67（95% CI 1.2～36.1）。结论　AECA检测对KD的早期诊断价值有限,但对冠状动脉瘤的发生具有预警意义。AECA可能与抗-PR3相互协同在KD冠状动脉损伤、进展至动脉瘤过程中起一定的作用。