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Search Results: 1 - 10 of 2015 matches for " ELISA "
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Comparative antibody study for antigen detection in urine specimens for diagnosis of blastomycosis using a competitive enzyme-linked immunosorbent assay  [PDF]
Amanda Searle, Gene Scalarone
Open Journal of Immunology (OJI) , 2012, DOI: 10.4236/oji.2012.24017
Abstract: Diagnosis of blastomycosis is often done using a combination of clinical signs and cytologic or histopathologic identification of the organism, Blastomyces dermatitidis, from infected tissues. However, these methods are time consuming, invasive, and still lead to misdiagnosis. A competitive enzyme-linked immunosorbent assay (ELISA) can be used for detection of B. dermatitidis antigens, which are present in urine specimens of infected patients. The current study evaluates the use of various antibodies for detection of antigen in dog urine specimens, to provide a better diagnosis of blastomycosis in the future. Our results show that different antibodies against B. dermatitidis produce various sensitivities for antigen detection. The most realistic antibodies for immunodiagnostic tests would be antibodies that can be obtained in larger quantities, i.e. vaccination using a yeast lysate in a laboratory setting. We found that these antibodies produce a comparable and reliable result to that of antibodies obtained from an infected patient.
Performance Characteristics of ELISA to Detect Bovine Viral Diarrhea Virus (BVDV) Antibodies Using Colostrum  [PDF]
Caitlin J. Jenvey, Andrew M. Weir, Michael P. Reichel, Peter D. Cockcroft
Open Journal of Veterinary Medicine (OJVM) , 2015, DOI: 10.4236/ojvm.2015.52006
Abstract: Colostrum contains substantially higher concentrations of immunoglobulins (Igs) when compared with serum or milk, which may improve the diagnostic sensitivity of an antibody ELISA when using colostrum. In this study, BVD was used as a model to identify the performance characteristics of colostrum and to assess the potential for increased ELISA sensitivity when compared with serum. Blood and colostrum samples were collected from cows within two dairy cattle herds: a previously infected and BVD-vaccinated Holstein-Friesian (positive herd) herd, and a bulk-tank milk antibody negative (negative herd) Jersey herd. All samples were tested using a commercial BVDV antibody ELISA. Median sample-to-positive (S/P) colostrum ratios were significantly higher than their respective serum counterparts, and positive herd S/P ratios were significantly higher than the respective negative herd values (P < 0.001). Using the manufacturer’s recommended serum dilution (1:5) and colostrum dilution (undiluted), and a cut-off threshold S/P ratio of 0.2, diagnostic sensitivity (DSe) and diagnostic specificity (DSp) for colostrum were 100% and 70%, respectively. These values increased to 100% DSe and 100% DSp with an increase in cut-off threshold S/P to 0.5. At a sample dilution of 1:100, the DSe of colostrum was 90% and significantly higher compared with serum (DSe 17%). Colostrum has the potential to improve identification of previously infected animals, either individually, or when using pooled samples.
Varietal Reaction of Cucumber against Cucumber mosaic virus  [PDF]
Asma Akbar, Zahoor Ahmad, Farzana Begum,   Ubairah, Neelam Raees
American Journal of Plant Sciences (AJPS) , 2015, DOI: 10.4236/ajps.2015.67090
Abstract: Family Cucurbitaceae is primarily found in the warmer regions of the world. It is the major family for economically important species, particularly edible fruits. In Pakistan cucurbits occupies an area of 28,600 ha with a very low production in Khyber Pukhtunkhwa due to many biotic and abiotic stresses. The reason is also the lack of growers’ awareness about the diseases and the cultural practices adopted to provide favorable environment for development of epidemics. Viral diseases such as Cucumber mosaic virus (CMV) cause losses as high as 100%. Various control strategies are being used to control CMV. The aim of the current study was to screen out different verities and to find the most resistant one against CMV. CMV isolate was collected from farmer’s field at the site of TaruJaba during a survey of cucurbit crops. The identity of the virus was confirmed through DAS-ELISA using diagnostic kit (ADGEN, UK). Seventeen cucumber germplasm seeds were sown in earthen pots in which fourteen were germinated and exhibited characteristics symptoms of the virus while none of them showed resistance against CMV. Symptoms’ expression was delayed in summer green and local green till 12 days post inoculation. While in khyber, Diamond, VEGAF1 and Yousaf, symptoms started to appear soon after inoculation categorizing them as highly susceptible. No resistance is found in available commercial germplasm, so more germplasm from different area of Pakistan should be tested for resistance against CMV. If no resistance is found locally imported, germplasm can be evaluated for a source of resistance against the prevalent isolates of CMV.
Comparative ELISA reagents for detection of hepatitis B surface antigen (HBsAg)
Camargo, I. F.;Gaspar, A. M. C.;Yoshida, C. F. T.;
Memórias do Instituto Oswaldo Cruz , 1987, DOI: 10.1590/S0074-02761987000200005
Abstract: conjugates of goat anti-hbs igg and horseradish peroxidase (hrp) prepared by two different methods, one using naio4 and the other spdp, were compared. anti-hbs antibodies obtained from goat, rabbit and guinea-pig were tested as capture serum. the elisa showed a sensitivity similar to ria and a level of antigen captation ranging from 4.37 to 8.75 nanograms/ml was obtained when rabbit or guinea-pig captures were used combined with both naio4 or spdp conjugates.
Comparative Evaluation of Fast Enzyme Linked Immunosorbent Assay (Fast-ELISA) and Standard-ELISA For The Diagnosis Of Human Hydatidosis
MB Rokni,S Lesan,Massoud J,EB Kia
Iranian Journal of Public Health , 2006,
Abstract: Fast enzyme linked immunosorbent assay (Fast-ELISA) was compared with the standard ELISA for the diagnosis of human hydatidosis. Seventy serum samples including 30 from hydatidosis patients (surgically confirmed), healthy control individuals not infected with any parasitic diseases (n=/20) and from others with different parasitic infections including, toxocariosis (n=5), fasciolosis (n=5), trichostrongylosis (n=5), and strongyloidosis (n=5) were analysed for anti-hydatid IgG antibodies using sheep hydatid cyst fluid antigen. The sensitivity, specificity, positive and negative predictive values, as well as validity of the test were found as 96.7%, 95.2%, 93.7%, 97.5% and 96% for conventional ELISA, while these paramters for fast-ELISA were respectively as follows: 100%, 97.5%, 96.7%, 100% and 98.8%. Regarding standard-ELISA 3μg/ml of antigen, serum dilution of 1:500, conjugate dilution of 1:3000 and 30 min incubation were found optimal, while for fast-ELISA 3μg/ml of antigen, serum dilution of 1:125, conjugate dilution of 1:1000 and 5 min incubation were utilized. The present study indicates that fast ELISA can easily be performed in place of the standard ELISA for the serodiagnosis of human hydatidosis with the advantage of minimising consumed time and manpower hours. Moreover, this test can be utilized in screening tests to diagnos human hydatidosis.
The Development and Application of an Indirect ELISA Test for the Detection of Chicken Anaemia Virus (CAV) by VP1 in Chicken Flock Serum  [PDF]
Elham O. Mahgoub
Open Journal of Genetics (OJGen) , 2014, DOI: 10.4236/ojgen.2014.44029
Abstract:

Chicken anaemia virus (CAV) causes a viral disease in chickens worldwide and thus has economic importance. The main aim of this study was to develop a rapid, sensitive and specific VP1-CAVI indirect ELISA for the detection of CAV infection. The CAV-VP1, was separately cloned and expressed in recombinant E. coli. The purified recombinant CAV-VP1 protein was then coated as an antigen on an ELISA plates to evaluate its reactivity against chicken sera. The resulting indirect ELISA was then compared with a commercial ELISA. The specificity and sensitivity of the indirect ELISA were measured as 93.3% and 100%, respectively. A t-test produced a t-value of 15.805 for the indirect ELISA and revealed a significant difference between CAV-positive serum and CAV-negative serum (p-value of 0.001). For the second variable (i.e., a commercial ELISA), the t-test yielded a t-value of 5.063, which revealed a significant difference between CAV-positive serum and CAV-negative serum (p-value of 0.015). This intervention produces statistically significant improvements in both variables (p-values < 0.05). The correlation coefficient for the indirect ELISA was r = 0.93. Therefore, this work can be considered as a new achievement in diagnosis for Chicken anaemia virus in chicken flocks.

Comparative study of haemagglutination inhibition, Agar gel precipitation test, Serum neutralization and Enzyme linked immunosorbent assay for detection to avian influenza viruses  [PDF]
Shahid Faraz, Muhammad Abubakar, Mohammad Farooque, Sarfaraz Ali Fazlani, Ghluam Hussain Jaffar
Health (Health) , 2010, DOI: 10.4236/health.2010.22016
Abstract: The sensitivity, specificity and reproducibility of the serological tests for detection of avian in-fluenza viruses were carried-out by using Ham- agglutination inhibition (HI), Agar gel precipita-tion test (AGPT), and Enzyme linked immu-nosorbent assay (ELISA) and Serum neutraliza-tion test. The geometric mean titre (GMT) of hae- magglutination inhibition antibodies recor- ded as log2 indicated that the post vaccination titres in the field were on higher side i.e., 7.9 for H7 and 5.9 for H9. The correlation between HI titre and AGPT affirmed that for the AGPT test need high antibody titre for positive reaction. The pooled sera were also used to correlate the se-rum neutralization test and enzyme linked im- muno-sorbent assay. The serial two fold dilute- ons were tested for the serum neutralization ac- tivity and concluded that the HI titre log2 4 pro-vided 100% protection, than 52% and 45% pro-tection in 1:2 and 1:4 dilution was recorded, respectively. Similarly, the ELISA test showed positive results up to 1:16 HI titre, i.e. log2 4 and confirmed the linear relation between these two serological tests. In HI test, the concentration of antigen can influence the result. It also needs careful preparation of concentration of eryth-rocyte suspension. Agar Gel immuno-diffusion is basically a qualitative test as it can not de-termine the quantity of antigen or antibody with the help of this test. It lacks the level of sensi-tivity as offered by other test. If serum neutrali-zation test is performed on a pooled serum sam- ples, then it could lead to a false conclusion on antibodies status. ELISA is most sensitive, spe-cific and accurate as compare to all other sero-logical tests.
Rapid immunodiagnostic assays for Mycobacterium Tuberculosis infection  [PDF]
Roba M. Talaat, Gamal S. Radwan, Abdelaziz A. Mosaad, Saleh A. Saleh, Kalied Bassiouny
Health (Health) , 2010, DOI: 10.4236/health.2010.23025
Abstract: Purpose: There is a need for a continued effort to develop rapid immunodiagnostic assays for tuberculosis (TB) infection with greater sensitivity and specificity that can be used in the field and in the laboratory and that can be formatted for use with multiple species. This would help to obtain definitive early diagnosis of TB. The present study was developed to determine the role of using early secreted antigenic target-6 (ESAT-6) in immunodiagnosis of Mycobacterium tuberculosis. Methods: Serum samples were obtained from TB infected patients and normal healthy controls. Two rapid immunodiagnostic assays (Enzyme-linked immunosorbent assay (ELISA) and Immunoblotting) were performed. Results: The sensitivity of immunoblotting assay was 100%; however, ESAT-6 antigen was not able to discriminate between patients and normal controls. Application of direct ELISA using ESAT-6 antigen yielded 97.6% sensitivity and 75% specificity for the diagnosis of TB infection. Conclusion: In conclusion, the detection of antibodies against ESAT-6 antigen in the sera of TB patients by direct ELISA could be used as a preliminary assay for diagnosis of human M. tuberculosis infection. A combination of the ELISA with either radiological or microscopic examination is required to overcome the low specificity of the assay for negative results.
Antigen Detection in Canine Blastomycosis: Comparison of Different Antibody-Antigen Combinations in Two Competitive ELISAs  [PDF]
Debra Andrae, Katheryn Birch, Trevor Bybee, Thomas Ritcher, Jason Werth, Gene M. Scalarone
Open Journal of Medical Microbiology (OJMM) , 2012, DOI: 10.4236/ojmm.2012.23016
Abstract: This present study was designed to evaluate four different Blastomyces dermatitidis antibody-antigen combinations (B5896 and T-58 antibodies and B5896 and WI-R antigens) for the detection of antigen in 36 urine specimens from dogs with blastomycosis using a standard indirect ELISA (STD) and a biotin-streptavidin ELISA (B-SA). The antigen detection sensitivity values ranged from 81% (B-SA: T-58 Ab + WI-R Ag) to 100% (STD and B-SA: B5896 Ab + WI-R Ag; B5896 Ab + B5896 Ag) with the antibody-antigen combinations in the two assays. Optimal detection was evidenced when the B5896 Ab was allowed to react with the urine specimens for 30 min at 37?C and then placed in the B-SA ELISA plates containing the B5896 Ag. The greatest absorbance value obtained with this antibody-antigen com-bination was 0.903 (range of 0.596 - 0.903) as compared to the control value of 1.246. The difference between the control absorbance and the test absorbance values was 0.343 which was considerably greater than the control-test values with the other combinations. This study thus showed that the results obtained in antigen detection assays are dependent upon the antibody used to react with the urine specimens as well as the antigen used in the enzyme immunoassay.
Detection of Antibodies in Serum Specimens from Dogs with Blastomycosis with Lysate Antigens Prepared from Four Blastomyces dermatitidis Dog Isolates: Individual Antigens vs Antigen Combinations  [PDF]
Jamie L. VanDyke, Alex Boyd, Jesse Sorensen, Tylor Hine, Christina Rayner, Angel Zamora, Gene M. Scalarone
Open Journal of Veterinary Medicine (OJVM) , 2013, DOI: 10.4236/ojvm.2013.34037
Abstract:

Blastomycosis, the systemic fungal infection of humans and animals, has presented a diagnostic challenge to clinicians and laboratory personnel for many years. Our laboratory has been concentrating on attempting to develop antigenic reagents from the yeast phase of various isolates of Blastomyces dermatitidis and to evaluate these lysate antigens with regard to antibody detection in blastomycosis. The aim of this current study was to evaluate yeast phase antigens prepared from four dog isolates of B. dermatitidis and to evaluate their efficacy, when used individually or in combination, for antibody detection in sera from dogs with blastomycosis. Mean absorbance values using the ELISA to assay 24 serum specimens (Trial 1) ranged from 0.588 with an individual lysate antigen to 0.992 when three reagents were combined. Eight of the lysates exhibited mean absorbance values ranging from 0.992 to 0.915 with 7 out of 8 being lysate antigen combinations. Mean absorbance values with the other 6 lysates ranged from 0.899 to 0.588. In Trial 2, the 6 most sensitive reagents from Trial 1 were assayed against 10 highly reactive dog sera. The results of Trial 2 showed that 5 antigen combinations detected antibody to a greater degree than the individual lysate antigen. Combinations of northern and southern antigens were able to detect antibody in serum specimens from either of these geographical regions. Comparative studies are continuing to further evaluate various lysate antigen combinations for antibody detection in blastomycosis.

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