scholarly journals Dot Blot Assay for Detection of Antidiacyltrehalose Antibodies in Tuberculous Patients

1999 ◽  
Vol 6 (5) ◽  
pp. 686-689 ◽  
Author(s):  
Lucio Vera-Cabrera ◽  
Adrian Rendon ◽  
Manuel Diaz-Rodriguez ◽  
Vera Handzel ◽  
Adalbert Laszlo

ABSTRACT A simple dot blot test with diacyltrehalose (DAT) as the antigen was developed to detect anti-DAT antibodies in tuberculous patients. To enhance antigen-antibody reaction detection, rabbit serum raised against human immunoglobulins was used prior to incubation with a protein A-colloidal gold complex. With the dot blot system, it was possible to obtain a sensitivity similar to that of enzyme-linked immunosorbent assay (ELISA) and a specificity of 97.14%, versus a specificity of 94.29% by the ELISA. We conclude that this simple and fast assay could be used in places where ELISA equipment is not easy available and that it might also be applicable with otherMycobacterium tuberculosis immunogenic antigens.

Author(s):  
George H. Herbener ◽  
Antonio Nanci ◽  
Moise Bendayan

Protein A-gold immunocytochemistry is a two-step, post-embedding labeling procedure which may be applied to tissue sections to localize intra- and extracellular proteins. The key requisite for immunocytochemistry is the availability of the appropriate antibody to react in an immune response with the antigenic sites on the protein of interest. During the second step, protein A-gold complex is reacted with the antibody. This is a non- specific reaction in that protein A will combine with most IgG antibodies. The ‘label’ visualized in the electron microscope is colloidal gold. Since labeling is restricted to the surface of the tissue section and since colloidal gold is particulate, labeling density, i.e., the number of gold particles per unit area of tissue section, may be quantitated with ease and accuracy.


2018 ◽  
Vol 50 (3) ◽  
pp. 229-235 ◽  
Author(s):  
Suresh Bokoliya ◽  
Shripad Patil ◽  
Madhu Nagappa ◽  
Arun Taly

AbstractObjectiveTo assess the practicality of dot-blot testing for rapid and sensitive detection of the antiacetylcholine receptor (anti-AChR) antibodies in myasthenia gravis (MG).MethodsIn this case-control study, we tested serum specimens of 85 patients with MG, 85 healthy control individuals, and 85 patients without MG who have other autoimmune and neurological illnesses. All the serum specimens were tested for anti-AChR antibodies using 3 assays: in-house enzyme-linked immunosorbent assay (ELISA), the dot-blot assay, and commercial ELISA.ResultsIn-house ELISA, commercial ELISA, and dot-blot test results were positive for anti-AChR antibodies in 65 (76.5%) patients with MG. The results of all 3 tests were negative for anti-AChR antibodies in healthy controls and patients without MG. We observed perfect concordance (K = 1, P <.001) between all 3 tests. In-house ELISA correlated significantly (r = 0.873, P <.001) with commercial ELISA. In-house ELISA and the dot-blot test demonstrated similar diagnostic performance in detecting anti-AChR antibodies.ConclusionsThe dot-blot assay is a simple, nonradioactive immune assay for rapid detection of anti-AChR antibodies in MG.


2011 ◽  
Vol 24 (1) ◽  
pp. 42-50 ◽  
Author(s):  
Ming Yang ◽  
Rebekah van Bruggen ◽  
Wanhong Xu

Seneca Valley virus (SVV), a member of the Picornaviridae family, was implicated in a suspicious vesicular disease discovered in pigs from Canada in 2007. Because any outbreak of vesicular disease in pigs is assumed to be foot-and-mouth disease (FMD) until confirmed otherwise, a test for diagnosing the presence of SVV would be a very useful tool. To develop the diagnostic tests for SVV infection, 5 monoclonal antibodies (mAbs) were produced from mice immunized with binary ethylenimine (BEI)-inactivated SVV. Using a dot blot assay, the reactivity of the mAbs was confirmed to be specific for SVV, not reacting with any of the other vesicular disease viruses tested. The mAbs demonstrated reactivity with SVV antigen in infected cells by an immunohistochemistry assay. An SVV-specific competitive enzyme-linked immunosorbent assay (cELISA) was developed using BEI-inactivated SVV antigen and a mAb for serodiagnosis. The cELISA results were compared to the indirect isotype (immunoglobulin [Ig]M and IgG) ELISA and the virus neutralization test. All SVV experimentally inoculated pigs exhibited a positive SVV-specific antibody response at 6 days postinoculation, and the sera remained positive until the end of the experiment on day 57 (>40% inhibition) using the cELISA. The cELISA reflected the profile of the indirect ELISA for both IgM and IgG. This panel of SVV-specific mAbs is valuable for the identification of SVV antigen and the serological detection of SVV-specific antibodies.


2001 ◽  
Vol 8 (1) ◽  
pp. 79-84 ◽  
Author(s):  
Paul T. Fawcett ◽  
Carlos D. Rose ◽  
Sandra M. Budd ◽  
Kathleen M. Gibney

ABSTRACT This study evaluated the effects of vaccination with OspA on the use of serologic tests as aids in the diagnosis of Lyme borreliosis. Sera from control and OspA-immunized mice and from OspA-immunized human volunteers were tested for serologic reactivity to Borrelia burgdorferi. Testing was performed with samples obtained prior to administration of vaccine and at 30 days following administration of an initial and a second dose of OspA vaccine. The assays used to assess serologic reactivity included an in-house-developed enzyme-linked immunosorbent assay (ELISA), an in-house-developed Western blot assay, two commercial Western blot tests, and a commercially available dot blot assay. Data obtained from this study demonstrate that immunization with the OspA vaccine will cause ELISA to yield positive results (as reported previously) for the majority of vaccine recipients. Results obtained from Western blot analysis indicate that vaccination with recombinant OspA induces production of antibodies which bind to several different borrelial proteins. The degree of reactivity detected by Western blotting varied greatly between the three assays used. The in-house assay showed the least reactivity, while one commercial Western blot test actually yielded positive test results for infection with B. burgdorferi. The usefulness of all three Western blot assays for the diagnosis of potential infection in a vaccine recipient is severely limited by the extensive reactivity caused by vaccination alone. Antibodies produced in response to OspA vaccination did not significantly affect the performance of the dot blot test; thus, it could provide a reliable means to test for infection withB. burgdorferi in OspA vaccine recipients.


1985 ◽  
Vol 33 (12) ◽  
pp. 1247-1251 ◽  
Author(s):  
C Manigley ◽  
J Roth

We report the development of a new light-microscopic double-staining technique using colloidal gold as sole marker. The contrasting color to the red of colloidal gold is achieved by the application of photochemical silver reaction. The silver reaction, which is principally performed at the end of the first staining sequence, converts the red color of a gold-labeled reagent into black. This contrasts clearly with the red coloration that results from the second incubation sequence without silver reaction. For antigen double staining, the same protein A-gold complex can be used to provide the black and the red color, thus rendering the technique very economical. Alternatively, combination of protein A-gold immunolocalization and lectin-gold staining is possible, as is combined lectin-gold staining.


2010 ◽  
Vol 17 (9) ◽  
pp. 1398-1406 ◽  
Author(s):  
Ming Yang ◽  
Alfonso Clavijo ◽  
Jill Graham ◽  
John Pasick ◽  
James Neufeld ◽  
...  

ABSTRACT A panel of monoclonal antibodies (MAbs) was generated from mice immunized with binary ethylenimine (BEI)-inactivated H7N1 (A/TK/ON/18-2/00) virus. Using a dot blot assay, six of seven MAbs reacted with viruses of the H7 subtype, but not with any of the other 15 hemagglutinin (HA) subtypes tested. Four of the seven MAbs reacted with 14 different H7 isolates, indicating that the MAbs binding epitopes are conserved among viruses of the H7 subtype. The binding epitopes of all seven MAbs were conformational and reacted with the HA1 fraction of the HA protein in Western blots under nonreducing conditions. Applications of these MAbs in the development of rapid tests for H7 subtype viruses were evaluated. The MAbs demonstrated reactivity with AI virus H7 antigen in immunofluorescence and immunohistochemistry assays. Monoclonal antibody 3 showed a very strong immunostaining in the formalin-fixed and paraffin-embedded tissue from the H7N3 virus-infected chicken. A double-antibody sandwich (DAS) enzyme-linked immunosorbent assay (ELISA) was developed using two of the MAbs. The DAS ELISA specifically detected all H7 strains tested in this study. A competitive ELISA (cELISA) for the detection of H7-specific antibodies was evaluated using one MAb and BEI-inactivated H7N1 virus as the antigen. All infected birds showed positive antibody responses at 7 days postinfection. The sensitivity of this cELISA was comparable with that of an influenza A nucleoprotein-based cELISA. This panel of MAbs is valuable in the development of various immunoassays.


Author(s):  
David W. Dorward ◽  
Claude F. Garon

Despite the often serious pathological ramifications of Lyme disease, Borrelia burgdorferi, the causative agent, is rarely demonstrated in nor isolated from naturally-infected mammalian hosts. This dilemma has led to suggestions that a limited number of spirochetes expel extracellular bioproducts that may contribute to the clinical symptoms. Currently, no mammalian toxins have been attributed to B. burgdorferi, however, the production of extracellular vesicles by this bacterium was recently described. In order to assay the possible presence of such extracellular material in infected hosts, we developed a sensitive electron microscopic assay to detect and characterize B. burgdorferi products in biological samples.Polyclonal rabbit serum was raised against purified B. burgdorferi vesicles and against an electrophoretically-purified 83 kilodalton (kDa) vesicle-associated protein. After purification of IgG from the sera, anti-vesicle F(ab’)2 fragments were produced and used to “activate” parlodion-coated grids. Such grids were incubated with cultured spirochetes, or with fluids and tissues from infected and non-infected mammals and ticks. Captured antigens were then labeled with anti-83 kDa IgG and Protein A-colloidal gold conjugates, and/or lectin-colloidal gold conjugates, then examined and characterized by electron microscopy.


2002 ◽  
Vol 70 (2) ◽  
pp. 732-740 ◽  
Author(s):  
Heather P. Masri ◽  
Cynthia Nau Cornelissen

ABSTRACT The gonococcal transferrin receptor complex comprises two iron-regulated proteins, TbpA and TbpB. TbpA is essential for transferrin-iron uptake and is a TonB-dependent integral outer membrane protein. TbpB is thought to increase the efficiency of iron uptake from transferrin and is lipid modified and surface exposed. To evaluate the structure-function relationships in one of the components of the receptor, TbpA, we created constructs that fused individual putative loops of TbpA with amino-terminal affinity tags. The recombinant proteins were then overexpressed in Escherichia coli, and the fusions were recovered predominately from inclusion bodies. Inclusion body proteins were solubilized, and the epitope fusions were renatured by slow dialysis. To assess transferrin binding capabilities, the constructs were tested in a solid-phase dot blot assay followed by confirmatory quantitative chemiluminescent enzyme-linked immunosorbent assays. The constructs with only loop 5 and with loops 4 and 5 demonstrated dose-dependent specific ligand binding in spite of being out of the context of the intact receptor. The immunogenicities of individual TbpA-specific epitopes were investigated by generating rabbit polyclonal antisera against the fusion proteins. Most of the fusion proteins were immunogenic under these conditions, and the resulting sera recognized full-length TbpA in immunoblots. These results suggest that individual epitopes of TbpA are both immunogenic and functional with respect to ligand binding capabilities, and the vaccine implications of these findings are discussed.


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