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Hypersensitivity
Published in Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal, Principles of Physiology for the Anaesthetist, 2020
Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal
Immunodiffusion is used for the qualitative and quantitative analysis of antigens and antibodies in serum or body fluids. The method depends on a precipitation reaction of an insoluble antigen–antibody complex from soluble antigen and antibodies. The enzyme-linked immunosorbent assay (ELISA) is an immunoassay using enzyme-linked antibody or antigen (Figure 58.8). Either the antigen or the antibody can be linked to an enzyme (e.g. horseradish peroxidase or alkaline phosphatase). In the standard indirect ELISA, an antigen is adsorbed onto a polystyrene plate (solid phase). The antibody to be detected binds to this component, and a second enzyme-labelled antibody is then added. The substrate of the enzyme is added, producing a coloured reaction product that can be measured spectrophotometrically.
Inherited Differences in Alpha1-Antitrypsin
Published in Stephen D. Litwin, Genetic Determinants of Pulmonary Disease, 2020
Precise determinations of individual inhibitors can be made by immunologic techniques using specific antisera. Radial immunodiffusion [9,34-36] has proved particularly useful. By this method the normal concentration of alpha1-antitrypsin is 212 ± 32 mg/dl. The accuracy of this measurement largely depends on the purity of the preparation used as the standard. The presence of contaminating proteins in the standard would result in erroneously high estimates of alphai-antitrypsin. Some laboratories have therefore adopted the practice of expressing their results as percent of a pool of normal sera. Commonly used pools are available from Dr. Fagerhol* and from Dr. Pierce.†
Immunological Approaches
Published in Adorjan Aszalos, Modern Analysis of Antibiotics, 2020
Deborah E. Dixon, Susan J. Steiner, Stanley E. Katz
The radial immunodiffusion assay offers no overall advantages over the classic microbial diffusion procedures. The time element for immunodiffusion is not shorter (ranging from several hours to days), the accuracy of the measurement of the zones is no more precise, and the sensitivity of the technique is usually considerably less than can be achieved by microbial diffusion assays. The only advantage of the immunodiffusion technique is specificity. When sensitivity of detection is not a problem, specificity is a requirement, and antibody is plentiful, immunodiffusion could be a useful approach.
An overview of advancement in aptasensors for influenza detection
Published in Expert Review of Molecular Diagnostics, 2022
Varsha Gautam, Ramesh Kumar, Vinod Kumar Jain, Suman Nagpal
Although there are many identification strategies available today, such as rapid influenza diagnostic tests (RIDTs). Enzyme linked immunosorbent assay (ELISA). Double immunodiffusion (DID). Complement fixation test (CF). Hemagglutinin inhibition (HI). Nucleic acid-based assays (NATs), and real time polymerase chain reaction (RT-PCR), but their specificity and time effectiveness still make them less applicable. The flu virus is a ‘form shifter.’ and new plans have to be drawn periodically to improve the vaccine for that year’s influenza outbreak. It has been challenging because of the variability of the influenza strain. Therefore, early identification is the only key available. Present viral diagnosis relies on viral nucleic acid or protein components being selectively identified. Because of specialized laboratory requirements, culture methods can be excluded. Additionally, serological testing is ineffective, requires two sufficient specimens, and takes time. Rapid tests can only detect nucleic acids or a few viral antigens and encourage practical and informative diagnosis. Moreover, RT-PCR is still regarded as costly and time consuming, and ELISA testing does not offer a high degree of sensitivity [14].
Endemic mycoses: epidemiology and diagnostic strategies
Published in Expert Review of Anti-infective Therapy, 2020
Andrés Tirado-Sánchez, Gloria M. González, Alexandro Bonifaz
Demonstration of elevated levels of antibodies to C. immitis has been the sole basis for diagnosis in a small proportion of cases in HIV/AIDS patients [84]. Immunodiffusion is widely used to detect antibodies to C. immitis. Immunodiffusion is easier than tube precipitation or complement fixation; therefore, it is a useful resource [67]. Radioimmunoassay, immunofluorescence assay, and immunoblot (Western blot) are valuable diagnostic techniques [82,83]. In a recent study, Malo et al. [85], tested three immunoglobulin G (IgG) and immunoglobulin M (IgM) antibody detection methods using the MVista Coccidioides antibody detection EIA, and two commercial enzyme immunoassay (EIA) kits, the IMMY Omega EIA and the Meridian Premier EIA, observing that the sensitivity in the detection of IgG and IgM was higher in the MVista test (87.4% and 61.2% respectively); similarly, the specificity of IgG and IgM antibodies was higher for the MVista EIA (90% and 95.3% respectively), concluding that the MVista Coccidioides antibody detection EIA is sensitive and specific, including high-risk patients, for the detection of IgG and IgM antibodies.
Comparative toxicological characterization of venoms of Cerastes cerastes and Macrovipera mauritanica from Morocco and neutralization by monospecific antivenoms
Published in Toxin Reviews, 2020
Bouchra Makran, Laila Fahmi, Lotfi Boussada, Naoual Oukkache, Fatima Chgoury, Hakima Benomar, Noreddine Ghalim, Mustapha Lkhider
The production of antivenoms (anti-Cc and anti-Mm) as well as their immunoreactivity in front of two crude venoms and their purified fractions was initially controlled all along the immunization schedule according to the method described by Ouchterlony and Nilsson (1978). Immunodiffusion was carried out in gels 1% agarose–PBS with a concentration of 0.01% sodium azide. Central wells were loaded with 10 µL of undiluted antivenoms and the six peripheral wells with 2 µg/µL of crude venoms or their fraction purified. The glass slides were incubated at 25 °C for 24 at 48 h and precipitate bands were observed after staining with Coomassie Blue R250 and washing with methanol acetic acid. Developing of precipitin lines by serum indicated the presence of antivenom antibodies.