Anti-P30 IgA antibodies as prenatal markers of congenital toxoplasma infection

This study extends a previous study and confirms that the detection of anti-P30 IgA antibodies is very helpful in the diagnosis of acute acquired or congenital toxoplasmosis. Moreover, we demonstrate that an anti-P30 IgA response can be mounted in the fetuses infected by Toxoplasma gondii during their intra-uterine life as early as week 23 of gestation. A double-sandwich ELISA described in our previous work was used to detect anti-P30 IgA antibodies in 1378 human serum samples collected from 551 patients, including 162 fetuses whose mothers had been infected by T. gondii during pregnancy, 46 congenitally infected and 90 uninfected newborns and 253 women suspected of having been infected during pregnancy, including the mothers of fetuses and newborns previously described. Anti-P30 IgA antibodies were detected in all cases of acute toxoplasmosis but in no case of chronic toxoplasmosis: in the majority of cases, the IgA antibody titre fell below cut-off in 3-9 months. Among the 46 congenitally infected newborns, anti-P30 IgA antibodies were detected in sera of 41 infected newborns (38 at birth, two in the first months of life, one in the seventh month of life), while anti-P30 IgM antibodies were detected in only 30 cases at birth and in one case during the first month of life. Among 162 fetuses, anti-P30 IgA response was observed in five infected fetuses, but was not detected in either 152 uninfected fetuses or in five fetuses considered as infected. The absence or presence of anti-P30 IgA antibodies in the fetus is discussed in relation to the date of maternal infection and collection of the fetal blood. It clearly appears from our study that the combined testing of both IgM and IgA in the fetus and the newborn is essential for a more efficient diagnosis of infection.     

An enzyme-linked immunosorbent assay (ELISA) for the measurement of antibodies to different parts of the gram-negative lipopolysaccharide core region

Bovine serum albumin was complexed with the core antigens of either Escherichia coli J5 LPS, Salmonella minnesota R595 LPS or E. coli lipid A. These core-BSA complexes were used for solid-phase coating in ELISAs for anti-core antibodies. Antibodies, binding to various parts of the core region were easily quantified in a single experimental set-up, which was hitherto not possible. The ELISA has only 3 incubation steps and is not costly as only moderate amounts of the core antigens (i.e., 1 microgram per test) were needed for coating. The sensitivity proved to be excellent and the complexes were biologically fully active (compared to native, smooth LPS), which make them suitable for the screening (after fusion) of monoclonal anti-core antibodies. Another possible application is the large-scale screening of blood-bank sera in order to find samples with a high anti-core antibody content.     

Induction of specific anti-actin antibodies and their measurement by ELISA technique.

Using the ELISA technique we have been able to quantify antibodies directed against actin and to follow the kinetics of antibody production. Specific anti-actin antisera have been raised in rabbits by immunization with chemically modified white muscle rabbit actin. Two or three dinitrophenyl groups linked per actin molecule were sufficient to break natural tolerance, while linkage of three phosphorylcholine groups to actin was not.     

Horizontal transmission of hepatitis B virus infection in household contacts, Pune, India

The study was undertaken to detect the risk of infection, if any, among 193 household contacts of 40 hospitalised hepatitis patients (group I) with hepatitis B surface antigen (HBsAg) in their blood. As a control group, 103 household contacts of 27 hospitalised hepatitis patients who were negative for HBsAg (group II) were investigated. The family contacts of the former group had a significantly higher prevalence of HBV infection than those of the latter group (P less than .001). Significant differences were observed both in the prevalence of HBsAg (P less than .05) and antibody to HBsAg (anti-HBs) (P less than .025) between the two groups. IgM antibody to hepatitis B core antigen (anti-Hbc-IgM) was detected in 32 out of the 39 (82%) sera tested from the patients of group I with HBsAg. A statistically significant difference (P less than .005) of HBV prevalence was also found in the contacts of these 32 patients suffering from acute hepatitis B as compared to the contacts of the patients of group II. Overall, the children of the first group showed a significantly higher prevalence of HBsAg as compared to the second group. All the children with HBsAg were positive for HBeAg also, but were negative for anti-HBc-IgM. Anti-HBs was detected in a significantly larger number of adult females. Spouses were found to be affected more than other relatives. A significant difference (P less than .025) was noted in the number of families having HBV markers in group I (80.0%) as compared to those in group II (48.1%).(ABSTRACT TRUNCATED AT 250 WORDS)     

生物素─链霉亲和素系统在检测巨细胞病毒抗体中的应用

本文用自制ＣＭＶ抗原和生物素－链霉亲和素系统试剂，通过最适条件的对比，建立了检测人血清中抗巨细胞病毒ＩｇＭ、ＩｇＡ类抗体的ＢＳＡ－ＥＬＩＳＡ，并与普通ＥＬＩＳＡ作比较，结果表明，ＢＳＡ－ＥＬＩＳＡ的非特异性吸附明显低于普通ＥＬＩＳＡ，与普通ＥＬＩＳＡ相比，抗体效价分别提高５和７倍，阳性率分别提高６８％和１５３．５％。在实际工作中曾用ＢＳＡ－ＥＬＩＳＡ检测临床样品１６５份，就所得结果进行分析。表明ＢＳＡ－ＥＬＩＳＡ检测ＣＭＶＩｇＭ和ＩｇＡ可提高特异性和灵敏度，值得推广应用。     

Production of transforming growth factor-beta 1 (TGF-beta1) by blood monocytes from patients with different clinical forms of leprosy

In the present study, the concentration of TGF-beta1 secreted by adherent cells isolated from human peripheral blood mononuclear cells (PBMC) and either stimulated with PGL-1 or lipopolysaccharide (LPS) or left unstimulated was determined by ELISA. The cells were isolated from untreated patients with different clinical forms of leprosy and healthy individuals. The adherent cells exhibited spontaneous release of TGF-beta1 in all clinical forms of leprosy and in healthy individuals; however, lepromatous leprosy/borderline leprosy (LL/BL) patients presenting erythema nodosum leprosum (ENL) displayed significantly higher concentrations of TGF-beta1 than either the other patients studied or the controls. These high TGF-beta1 levels were consistently observed when LL/BL ENL cells were stimulated with phenolic glycolipid (PGL-1) or LPS, and even in the absence of a stimulus (P < 0.01). The most significant differences in TGF-beta1 levels were observed when comparing the results in the presence of PGL-1 from ENL with, in order of significance: tuberculoid leprosy (TT) patients (P < 0.001), LL/BL patients without ENL (P < 0.01), healthy individuals (P < 0.01) and borderline-borderline/borderline-tuberculoid (BB/BT) patients with reversal reaction (RR) (P < 0.01). The BB/BT patients produced equivalent levels of TGF-beta1 compared with LL/BL patients without ENL, for all types of stimuli (P > 0.05). In contrast, TT patients produced the lowest levels of TGF-beta1 among all the subjects studied (both patients and healthy controls), especially following PGL-1 stimulation (P < 0.001, and P < 0.05, respectively). In conjunction with our previous data regarding TGF-beta1 expression in dermal lesions, it appears that TGF-beta1 probably plays different roles in leprosy: (i) to mediate a suppressive action locally, associated with the presence of PGL-1, and (ii) to induce proinflammatory effects when secreted systemically by monocytes, thereby acting as a modulatory cytokine in the acute inflammatory reactions of ENL and associated with the Th2 immune response in multibacillary forms of leprosy.     

大鼠单克隆抗体夹心ELISA法检测肝病病人血清中p21^ras蛋白

本文应用抗癌基因ｒａｓ表达产物Ｐ２１ｒａｓ蛋白的大鼠单克隆抗体建立的双抗体夹心ＥＬＩＳＡ法，检测了肝癌及癌病变前病人血清中ｐ２１ｒａｓ蛋白的浓度。所获阳性检出率分别为：慢性乙型肝炎为１３．０％（１２／９２），肝硬化为２７．８％（１０／３６）和肝癌为５０．０％（８／１６）。另外，对试验方法的敏感性、特异性及稳定性，以及检测Ｐ２１ｒａｓ蛋白与ＡＦＰ的关系进行了评价。结果表明，Ｐ２１ｒａｓ蛋白的过高表达发生在肝细胞癌变之前。提示在慢性乙型肝炎及肝硬化病人血清中检出Ｐ２１ｒａｓ蛋白，是预测肝细胞癌变的危险信号。     

Antibody response in laying hens with small amounts of antigen

Chicken antibodies offer many advantages over the traditional mammalian ones. A laying hen produces large amounts of yolk antibodies and the use of yolk antibodies eliminates the painful procedure of collecting blood from the animal. Thus, the use of chicken antibodies will reduce both the number of animals required to produce antibodies and also animal distress. Chicken antibodies also have several biochemical advantages compared to mammalian antibodies: they often increase the signal and reduce interference in many assays. However, the species chosen for antibody production have usually been mammals. This is probably due to tradition, but also to limited knowledge about the production of chicken antibodies. We studied the immune response in the chicken using small amounts of mammalian antigen, and show that a good immune response can be obtained with 0.1–1.0 μg of bovine serum albumin.     

RAI16蛋白合成肽多克隆抗体的制备及初步应用

目的: 制备RAI16蛋白的合成肽多克隆抗体, 并进行初步鉴定和应用, 为研究RAI16蛋白的功能及作用机制获得重要的实验工具.方法: 应用Fmoc法化学合成RAI16蛋白N端第44～55位氨基酸的多肽, 经C18的RP-HPLC纯化后, 通过高碘酸钠法将纯化的RAI16蛋白的多肽与KLH交联; 皮下注射抗原免疫新西兰纯种大耳白兔, 加强免疫得到抗血清, 应用蛋白G纯化获得多克隆抗体.对纯化的抗体进行ELISA、免疫组化、 Western blot等初步鉴定和应用.结果: 化学合成RAI16蛋白N端第44～55位氨基酸的多肽, 纯化后多肽纯度为96% , 达到免疫用抗原标准.多肽与KLH交联, 用于免疫动物.经纯化后的抗体效价为1∶ 125 000.该多肽抗体可特异识别人脾脏组织中相对分子质量(Mr)约为55 000的RAI16蛋白.结论: 所制备的多克隆抗体能与天然RAI16蛋白发生特异性反应, 可应用于ELISA、免疫组化、免疫沉淀和Western blot等实验, 为确定RAI16蛋白的组织分布和亚细胞定位、研究RAI16蛋白的功能及作用机制提供了重要的实验工具.