scholarly journals Development of a Highly Specific RecombinantToxocara canis Second-Stage Larva Excretory-Secretory Antigen for Immunodiagnosis of Human Toxocariasis

2000 ◽  
Vol 38 (4) ◽  
pp. 1409-1413 ◽  
Author(s):  
Hiroshi Yamasaki ◽  
Kunioki Araki ◽  
Patricia Kim Chooi Lim ◽  
Ngah Zasmy ◽  
Joon Wah Mak ◽  
...  
Keyword(s):  
False Negative ◽  
Toxocara Canis ◽  
Recombinant Antigen ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Cross Reactions ◽  
Second Stage ◽  
Secretory Antigen ◽  
The Cross ◽  
Excretory Secretory Antigen

The specificity of the recombinant Toxocara canisantigen developed for the immunodiagnosis of human toxocariasis was compared with that of the excretory-secretory antigen from T. canis second-stage larvae (TES) by enzyme-linked immunosorbent assay. A total of 153 human serum samples from patients infected with 20 different helminths, including 11 cases of toxocariasis, were examined. No false-negative reactions were observed for the toxocariasis cases. When the TES was used at concentrations of 0.5 and 0.125 μg/ml, cross-reactions were observed in 79 (55.6%) and 61 (43.0%) of 142 cases, respectively. In contrast, when the recombinant antigen was tested at a concentration of 0.5 μg/ml, cross-reactions were observed in 19 (13.4%) of 142 cases. At a concentration of 0.125 μg/ml, however, the cross-reaction rate decreased sharply to only 2.1%, corresponding to 3 of 142 cases. The cross-reactions occurred with one case each of gnathostomiasis, paragonimiasis withParagonimus miyazakii, and spirometriasis, in which high antibody titers were detected. In addition, the recombinant antigen showed negative reactions with serum samples from patients infected with Ascaris and hookworms, which are the most common parasites in the world. These findings are also supported by experiments with animals infected with Ascaris and hookworm. From these results, the recombinant antigen is highly specific for toxocariasis and may provide more reliable diagnostic results than other methods.

scholarly journals Standardization of dot-ELISA for the serological diagnosis of toxocariasis and comparision of the assay with ELISA

1992 ◽  
Vol 34 (1) ◽  
pp. 55-60 ◽  
Author(s):  
Eide Dias Camargo ◽  
Paulo Mutuko Nakamura ◽  
Adelaide José Vaz ◽  
Marcos Vinícius da Silva ◽  
Pedro Paulo Chieffi ◽  
...  
Keyword(s):  
Low Cost ◽  
Clinical Signs ◽  
Toxocara Canis ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Specific Antibodies ◽  
Normal Individuals ◽  
Before And After ◽  
Dot Elisa ◽  
Stability Time

The dot-enzyme-linked immunosorbent assay (dot-ELISA) was standardized using somatic (S) and excretory-secretory (ES) antigens of Toxocara-canis for the detection of specific antibodies in 22 serum samples from children aged 1 to 15 years, with clinical signs of toxocariasis. Fourteen serum samples from apparently normal individuals and 28 sera from patients with other pathologies were used as controls. All samples were used before and after absorption with Ascaris suum extract. When the results were evaluated in comparison with ELISA, the two tests were found to have similar sensitivity, but dot-ELISA was found to be more specific in the presence of the two antigens studied. Dot-ELISA proved to be effective for the diagnosis of human toxocariasis, presenting advantages in terms of yield, stability, time and ease of execution and low cost.

scholarly journals Evaluation of a New Immunochromatographic Test Using Recombinant Antigen B8/1 for Diagnosis of Cystic Echinococcosis

2015 ◽  
Vol 53 (12) ◽  
pp. 3859-3863 ◽  
Author(s):  
Saul J. Santivañez ◽  
Mary L. Rodriguez ◽  
Silvia Rodriguez ◽  
Yashuito Sako ◽  
Agathe Nkouawa ◽  
...  
Keyword(s):  
Cystic Echinococcosis ◽  
High Specificity ◽  
Recombinant Antigen ◽  
Enzyme Linked Immunosorbent Assay ◽  
Parasitic Infections ◽  
Clinical Settings ◽  
Immunochromatographic Test ◽  
Serum Samples ◽  
Content Type ◽  
Elisa Format

Diagnosis of cystic echinococcosis (CE) is based on the identification of the cyst(s) by imaging, using immunodiagnostic tests mainly as complementary tools in clinical settings. Among the antigens used for immunodiagnosis, previous studies described a good performance of the recombinant antigen B8/1 (rAgB) in an enzyme-linked immunosorbent assay (ELISA) format; however, in remote parts of areas where the disease is endemic, the implementation of an ELISA is difficult, so a more simple, rapid, and reliable method such as the immunochromatographic test (ICT) is required. In this study, using a set of 50 serum samples from patients with surgically confirmed CE, we compared the performance of an ICT and that of an ELISA using the rAgB. The overall sensitivities of ICT and ELISA were not statistically different (78% versus 72%;P= 0.36). The overall agreement between both tests was moderate (κ = 0.41;P< 0.01). Concordance between ICT and ELISA was substantial or almost perfect for patients with liver involvement (κ = 0.65;P< 0.001) and patients with more than one hydatid cyst (κ = 0.82;P< 0.001), respectively. Moreover, specificity analysis using a total of 88 serum samples from healthy individuals (n= 20) and patients (n= 68) with other parasitic infections revealed that ICT had a specificity of 89.8%. ICT and ELISA had similar performance for the detection of specific antibodies toE. granulosus, and ICT had a high specificity, opening the possibility of using ICT as a screening tool in rural settings.

scholarly journals Development of an Electrochemical Immunosensor for Specific Detection of Visceral Leishmaniasis Using Gold-Modified Screen-Printed Carbon Electrodes

Biosensors ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 81 ◽  
Author(s):  
Beatriz R. Martins ◽  
Yanne O. Barbosa ◽  
Cristhianne M. R. Andrade ◽  
Loren Q. Pereira ◽  
Guilherme F. Simão ◽  
...  
Keyword(s):  
Visceral Leishmaniasis ◽  
Electrochemical Immunosensor ◽  
False Positives ◽  
Cross Reaction ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Cross Reactions ◽  
Asymptomatic Patients ◽  
Screen Printed Carbon Electrode ◽  
Screen Printed

Visceral leishmaniasis is a reemerging neglected tropical disease with limitations for its diagnosis, including low concentration of antibodies in the serum of asymptomatic patients and cross-reactions. In this context, this work proposes an electrochemical immunosensor for the diagnosis of visceral leishmaniasis in a more sensitive way that is capable of avoiding cross-reaction with Chagas disease (CD). Crude Leishmania infantum antigens tested in the enzyme-linked immunosorbent assay (ELISA) were methodologically standardized to best engage to the sensor. The antibodies anti-Trypanosoma cruzi and anti-Leishmania sp. Present in serum from patients with diverse types of CD or leishmaniasis were chosen. A screen-printed carbon electrode modified with gold nanoparticles was the best platform to guarantee effective adsorption of all antigens so that the epitope of specific recognition for leishmaniasis occurred efficiently and without cross-reaction with the evaluated CD. The current peaks reduced linearly after the recognition, and still were able to notice the discrimination between different kinds of diseases (digestive, cardiac, undetermined Chagas/acute and visceral chronic leishmaniasis). Comparative analyses with ELISA were performed with the same groups, and a low specificity (44%) was verified due to cross-reactions (high number of false positives) on ELISA tests, while the proposed immunosensor presented high selectivity and specificity (100%) without any false positives or false negatives for the serum samples from isolated patients with different types of CD and visceral leishmaniasis. Furthermore, the biosensor was stable for 5 days and presented a detection limit of 200 ng mL−1.

scholarly journals Combined Use of Indirect ELISA and Western Blotting with Recombinant Hepatocellular Carcinoma-Associated Antigen 59 Is a Potential Immunodiagnostic Tool for the Detection of Prepatent Haemonchus contortus Infection in Goat

Animals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 548 ◽  
Author(s):  
Muhammad Ali-ul-Husnain Naqvi ◽  
Sana Zahra Naqvi ◽  
Muhammad Ali Memon ◽  
Kalibixiati Aimulajiang ◽  
Muhammad Haseeb ◽  
...  
Keyword(s):  
Western Blot ◽  
Western Blotting ◽  
Haemonchus Contortus ◽  
Indirect Elisa ◽  
Fasciola Hepatica ◽  
False Negative ◽  
Cross Reactivity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Combined Use

Haemonchus contortus is recognized as one of the important health problems in small ruminants, leading to reduced production and economic loss for farmers worldwide. Prepatent diagnosis of H. contortus infection is crucial to improve control strategies as this helminth may remove up to one-fifth of total erythrocytes and may cause anemia, edema, diarrhea, and ultimately death in young animals. In this study, one of the excretory and secretory products, rHc-HCA59, was purified and used as antigen to detect specific antibodies in H. contortus infected goats during prepatent stage of infection using indirect enzyme linked immunosorbent assay (ELISA) as screening test. All goats (n = 38) were housed indoor, experimentally infected with 8000 infective larvae (L3) of H. contortus, and serum samples were collected prior to infection and at 14th day of infection. Immunoblotting was performed to confirm the results of indirect ELISA, evaluate the cross reactivity against rHc-HCA59 in sera of most common co-infecting parasites and rectify the false negative samples. Furthermore, three different batches of rHc-HCA59 were produced to evaluate the repeatability of ELISA. No eggs were detected in feces of all goats collected at 7th and 14th day of infection but, H. contortus eggs were detected at 21 days post infection in the feces. Indirect ELISA performed in this study showed 87% sensitivity and 100% specificity. The western blot analysis confirmed immunoreactivity in serum samples which scored positive in indirect ELISA and recognized the samples as negative which had OD450 lower than negative cut-off value in indirect ELISA. Furthermore, all false negative sera (n = 5) that had OD450 value between positive and negative cut-off value in rHc-HCA59 based ELISA were clearly positive in western blot. Moreover, no cross-reactivity was detected in ELISA and western blotting against rHc-HCA59 in positive sera of Toxoplasma gondii, Fasciola hepatica, and Trichinella spiralis. The results of this study concluded that combined use of indirect ELISA and western blotting with rHc-HCA59 is a potential immunodiagnostic tool for the detection of H. contortus infection during prepatent period in goats.

Three highly sensitive "bedside" serum and urine tests for pregnancy compared

1990 ◽  
Vol 36 (9) ◽  
pp. 1686-1688 ◽  
Author(s):  
H Christensen ◽  
H H Thyssen ◽  
O Schebye ◽  
A Berget
Keyword(s):  
Paired Comparison ◽  
False Negative ◽  
Diagnostic Sensitivity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Negative Results ◽  
False Negative Results ◽  
Significant Difference ◽  
Comparison Of The Results ◽  
Urine And Serum

Abstract We examined three enzyme-linked immunosorbent assay (ELISA) kits for human choriogonadotropin (hCG) (pregnancy tests) for use with urine and serum samples: the Tandem Icon II hCG Urine and Tandem Icon II hCG Serum, the NovoClone Target hCG Test, and the Abbott TestPacks hCG-urine and hCG-serum. Paired comparison of the results from each kit indicated that the NovoClone Target assay showed significantly lower diagnostic sensitivity (P less than 0.05) than did the Tandem Icon II or Abbott TestPack, both for urine and for serum samples. None of the products demonstrated any significant difference (P greater than 0.05) in diagnostic specificity, but the NovoClone Target kit showed several serious false-negative results with both urine and serum. Paired testing of urine kits vs serum kits also showed no significant differences (P greater than 0.05) in diagnostic sensitivity or specificity. We found the Abbott kits to be the most convenient to use and to read.

scholarly journals Comparison between available serologic tests for detecting antibodies againstAnaplasma phagocytophilumandBorrelia burgdorferiin horses in Canada

2015 ◽  
Vol 27 (4) ◽  
pp. 540-546 ◽  
Author(s):  
Gili Schvartz ◽  
Tasha Epp ◽  
Hilary J. Burgess ◽  
Neil B. Chilton ◽  
Katharina L. Lohmann
Keyword(s):  
Point Of Care ◽  
Fluorescent Antibody ◽  
Clinical Status ◽  
False Negative ◽  
Pairwise Comparison ◽  
Cross Reactivity ◽  
Multiplex Assay ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Serologic Tests

To investigate the agreement between available serologic tests for the detection of antibodies against Anaplasma phagocytophilum and Borrelia burgdorferi, 50 serum samples from horses of unknown clinical status and at low risk for infection were tested. In addition to a point-of-care enzyme-linked immunosorbent assay (pocELISA), the evaluated tests included 2 indirect fluorescent antibody tests (IFATs) for antibodies against A. phagocytophilum and an IFAT, an ELISA confirmed with Western blot, and the Lyme multiplex assay for antibodies against B. burgdorferi. For each pair-wise comparison between serologic tests, the difference in the proportion of seropositive results as well as kappa and the prevalence-adjusted, bias-adjusted kappa were calculated. The proportion of seropositive results differed significantly in each pairwise comparison of tests for detection of antibodies against A. phagocytophilum, and between the pocELISA and IFAT as well as between the pocELISA and Lyme multiplex assay for detection of antibodies against B. burgdorferi. Agreement based on kappa varied from poor to fair while agreement was improved when evaluating prevalence-adjusted, bias-adjusted kappa. Lack of agreement may be explained by differences in methodology between the evaluated tests, cross-reactivity or false-positive and false-negative tests. In addition to the limitations of serologic test interpretation in the absence of clinical disease, this data suggest that screening of horses for exposure to tick-borne diseases in nonendemic areas may not be warranted.

scholarly journals Analysis of Entamoeba histolytica Excretory-Secretory Antigen and Identification of a New Potential Diagnostic Marker

2011 ◽  
Vol 18 (11) ◽  
pp. 1913-1917 ◽  
Author(s):  
Weng Kin Wong ◽  
Zi Ning Tan ◽  
Nurulhasanah Othman ◽  
Boon Huat Lim ◽  
Zeehaida Mohamed ◽  
...  
Keyword(s):  
Human Serum ◽  
Entamoeba Histolytica ◽  
Amoebic Liver Abscess ◽  
Serum Samples ◽  
Pyruvate Phosphate Dikinase ◽  
Content Type ◽  
Human Serum Samples ◽  
Antigenic Proteins ◽  
Secretory Antigen ◽  
Excretory Secretory Antigen

ABSTRACTSerodiagnosis of amoebiasis remains the preferred method for diagnosis of amoebic liver abscess (ALA). However, the commercially available kits are problematic in areas of endemicity due to the persistently high background antibody titers. Human serum samples (n= 38) from patients with ALA who live in areas of endemicity were collected from Hospital Universiti Sains Malaysia during the period of 2008 to 2010. Western blots using excretory-secretory antigen (ESA) collected from axenically grownEntamoeba histolyticawere probed with the above serum samples. Seven antigenic proteins of ESA with various reactivities were identified, i.e., 152 kDa, 131 kDa, 123 kDa, 110 kDa, 100 kDa, 82 kDa, and 76 kDa. However, only the 152-kDa and 110-kDa proteins showed sensitivities above 80% in the Western blot analysis. All the antigenic proteins showed undetectable cross-reactivity when probed with healthy human serum samples (n= 30) and serum samples from other infections (n= 33). From the matrix-assisted laser desorption ionization–two-stage time of flight (MALDI-TOF/TOF) analysis, the proteins were identified as heavy subunits ofE. histolyticalectin andE. histolyticapyruvate phosphate dikinase, respectively. Use of theE. histolyticalectin for diagnosis of ALA has been well reported by researchers and is being used in commercialized kits. However, this is the first report on the potential use of pyruvate phosphate dikinase for diagnosis of ALA; thus, this molecule merits further evaluation on its diagnostic value using a larger panel of serum samples.

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