This document provides an overview of various immunological techniques including radioimmunoassay (RIA), rocket electroimmunodiffusion, chemical immunofluorescence, enzyme-linked immunosorbent assay (ELISA), and allergen testing. It describes the basic principles, methodologies, applications, advantages, and disadvantages of each technique. Radioisotopes commonly used in RIA and the steps of the RIA methodology are detailed. The document also discusses specific chemiluminescent compounds, types of ELISAs, and in vivo and in vitro allergen testing methods.
Immunoprecipitation is a technique used to isolate a protein of interest from a complex protein mixture using an antibody specific to that protein. The process involves lysing cells or tissue, incubating the lysate with the target antibody, precipitating the antibody-protein complex using beads coated with protein A/G, washing away non-specifically bound proteins, and then eluting the target protein for analysis. Common applications of immunoprecipitation include studying protein-protein interactions, determining protein expression levels, and enriching low abundance proteins for further analysis by techniques such as mass spectrometry.
Immunoprecipitation is a technique used to isolate a protein of interest from a complex protein mixture using an antibody that specifically binds to that protein. The key steps involve lysing cells, incubating the sample with the target antibody, precipitating the antibody-protein complex, washing away non-specific bindings, and then analyzing the isolated proteins. Immunoprecipitation can be used to study protein-protein interactions, identify proteins in complexes, and enrich low abundance proteins for further analysis.
Haptens are small molecules that are antigenic but not immunogenic on their own. They are unable to induce an immune response because they cannot activate helper T cells due to their inability to bind MHC proteins or activate B cells directly as they are univalent. However, when haptens are covalently bound to a carrier protein, they form immunogenic conjugates that can induce an immune response by activating helper T cells and B cells. Pioneering work by Karl Landsteiner demonstrated that antibodies produced against hapten-carrier conjugates were specific for the hapten and carrier epitopes. Common examples of haptens include drug molecules, peptides, and steroids. Hapten-protein conjugates can cause drug
This document discusses monoclonal and polyclonal antibodies, including their production and uses. Monoclonal antibodies are produced from a single clone and recognize a single epitope, while polyclonal antibodies recognize multiple epitopes of an antigen. Monoclonal antibodies are produced via cell fusion and screening of hybridomas, while polyclonal antibodies are produced by injecting animals with antigens to elicit an immune response. Both have advantages and disadvantages for diagnostic and therapeutic applications.
Ouchterlony double diffusion and Radial immunodifusionmicrobiology Notes
This document provides information on Ouchterlony double diffusion and radial immunodiffusion techniques. Ouchterlony double diffusion involves placing antigen and antibody in wells in an agar gel plate and observing the interaction over 24-48 hours. Possible results are identity, non-identity, or partial identity based on fusion of lines. Radial immunodiffusion is similar but incorporates antibody into the gel and antigens diffuse outward, forming measurable circular precipitin rings. Both techniques are used to detect and quantify the presence of antigens and antibodies.
It includes general introduction to antibodies; Monoclonal antibodies; comparison between Polyclonal & Monoclonal antibodies; Hybridoma Technology & Hyridoma Selection; advantages & disadvantages of mABs; Applications of mABs; Recombinant Monoclonal antibodies production through Antibody Engineering.
This document summarizes the technique of immunoprecipitation. It describes immunoprecipitation as a method to precipitate protein antigens out of solution using an immobilized specific antibody. The document outlines different applications of immunoprecipitation including measuring protein molecular weight, detecting post-translational modifications, and analyzing protein-protein interactions. It also describes different types of immunoprecipitation techniques such as co-immunoprecipitation, chromatin immunoprecipitation, and RNA immunoprecipitation.
Immunoprecipitation is a technique used to isolate a protein of interest from a complex protein mixture using an antibody specific to that protein. The process involves lysing cells or tissue, incubating the lysate with the target antibody, precipitating the antibody-protein complex using beads coated with protein A/G, washing away non-specifically bound proteins, and then eluting the target protein for analysis. Common applications of immunoprecipitation include studying protein-protein interactions, determining protein expression levels, and enriching low abundance proteins for further analysis by techniques such as mass spectrometry.
Immunoprecipitation is a technique used to isolate a protein of interest from a complex protein mixture using an antibody that specifically binds to that protein. The key steps involve lysing cells, incubating the sample with the target antibody, precipitating the antibody-protein complex, washing away non-specific bindings, and then analyzing the isolated proteins. Immunoprecipitation can be used to study protein-protein interactions, identify proteins in complexes, and enrich low abundance proteins for further analysis.
Haptens are small molecules that are antigenic but not immunogenic on their own. They are unable to induce an immune response because they cannot activate helper T cells due to their inability to bind MHC proteins or activate B cells directly as they are univalent. However, when haptens are covalently bound to a carrier protein, they form immunogenic conjugates that can induce an immune response by activating helper T cells and B cells. Pioneering work by Karl Landsteiner demonstrated that antibodies produced against hapten-carrier conjugates were specific for the hapten and carrier epitopes. Common examples of haptens include drug molecules, peptides, and steroids. Hapten-protein conjugates can cause drug
This document discusses monoclonal and polyclonal antibodies, including their production and uses. Monoclonal antibodies are produced from a single clone and recognize a single epitope, while polyclonal antibodies recognize multiple epitopes of an antigen. Monoclonal antibodies are produced via cell fusion and screening of hybridomas, while polyclonal antibodies are produced by injecting animals with antigens to elicit an immune response. Both have advantages and disadvantages for diagnostic and therapeutic applications.
Ouchterlony double diffusion and Radial immunodifusionmicrobiology Notes
This document provides information on Ouchterlony double diffusion and radial immunodiffusion techniques. Ouchterlony double diffusion involves placing antigen and antibody in wells in an agar gel plate and observing the interaction over 24-48 hours. Possible results are identity, non-identity, or partial identity based on fusion of lines. Radial immunodiffusion is similar but incorporates antibody into the gel and antigens diffuse outward, forming measurable circular precipitin rings. Both techniques are used to detect and quantify the presence of antigens and antibodies.
It includes general introduction to antibodies; Monoclonal antibodies; comparison between Polyclonal & Monoclonal antibodies; Hybridoma Technology & Hyridoma Selection; advantages & disadvantages of mABs; Applications of mABs; Recombinant Monoclonal antibodies production through Antibody Engineering.
This document summarizes the technique of immunoprecipitation. It describes immunoprecipitation as a method to precipitate protein antigens out of solution using an immobilized specific antibody. The document outlines different applications of immunoprecipitation including measuring protein molecular weight, detecting post-translational modifications, and analyzing protein-protein interactions. It also describes different types of immunoprecipitation techniques such as co-immunoprecipitation, chromatin immunoprecipitation, and RNA immunoprecipitation.
Immunoelectrophoresis is a technique that combines electrophoresis and immunodiffusion to separate and identify antigen components in a mixture. It involves applying an electric current to separate antigens in agar gel wells, then allowing the antigens to diffuse and react with antibodies placed in troughs cut into the gel. This results in the formation of precipitin lines that indicate reactions between individual antigens and antibodies, allowing different antigens to be identified based on the lines' position and shape. Immunoelectrophoresis is used in medical diagnostics to detect abnormal proteins and monitor antigen purity.
Immunological techniques use antigens and antibodies to detect pathogens or their components in patient specimens. Agglutination tests couple antigens or antibodies to particles and look for cross-linking and agglutination. Complement fixation tests measure complement-consuming antibodies by incubating specimens with complement and antigens. Enzyme immunoassays like ELISA use enzyme-linked antibodies to detect antigens and quantify antibodies. Precipitation tests look for visible precipitation of antigen-antibody complexes to detect antigens or antibodies.
This document describes single radial immunodiffusion (RID), a quantitative technique used to determine the concentration of an antigen in a sample. RID involves incorporating specific antibody into an agarose medium with a central well for the antigen sample. The antigen diffuses radially and reacts with the antibody, forming a visible precipitate ring whose diameter relates to the antigen concentration. The technique is simple, cost-effective, and can quantify immunoglobulins, complement components, or other antigens from biological fluids by measuring ring diameters against a standard curve.
Viral vectors are efficient tools for gene delivery due to viruses' ability to transfer DNA into host cells. The document discusses several types of viral vectors, including adenoviral, adeno-associated, retroviral, lentiviral, and baculovirus vectors. It provides details on the structure and genome organization of different viruses used to create these vectors. The document also explains the process of generating recombinant viral vectors by removing unnecessary viral genes and inserting genes of interest. Viral vectors allow for transient or stable gene expression and are useful for both research and clinical applications such as gene therapy and vaccine development.
An antigen is any substance that reacts with lymphocytes, while immunogens generate immune responses. Haptens are small molecules that require coupling to carriers to induce responses. Antibody-antigen binding depends on weak interactions between sites on antibodies and epitopes on antigens. Antibodies are produced with a wide variety of binding sites to recognize different antigenic determinants. Factors like foreignness, size, structure, and route of administration influence a substance's immunogenicity.
There are three major categories of antigenic determinants on immunoglobulin molecules: isotypic, allotypic, and idiotypic determinants. Isotypic determinants distinguish each antibody class and subclass within a species. Allotypic determinants are subtle amino acid differences encoded by different alleles of isotype genes. Idiotypic determinants are generated by the conformation of the amino acid sequences of the heavy- and light-chain variable regions specific for each antigen.
Antibody affinity is a measure of the strength of interaction between an antibody's antigen binding site and its target epitope. It is quantified by the affinity constant Ka, with higher values indicating tighter binding. A high affinity antibody binds its antigen more strongly and for longer than a low affinity antibody. Antibody avidity takes into account not just affinity but also the multivalency of antibodies and antigens, which allows for multiple binding interactions that further strengthen complex formation. High avidity can compensate for low individual binding affinities through cooperative multivalent binding effects.
This document discusses antibody purification methods. It begins with an introduction on the importance of purified antibodies for research and diagnostics. It then covers various sources of antibodies and different purification techniques including precipitation, ion exchange, size exclusion, and affinity chromatography using Protein A/G/L or antigen binding. The document emphasizes that "purified" antibodies can vary in terms of concentration, buffer components, purity level, and potential contaminants. The final buffer an antibody is in and whether it is specific IgG or total IgG can significantly impact its intended use.
The document discusses the nature of antigens and the major histocompatibility complex (MHC). It defines immunogens and antigens, noting that immunogens can trigger an immune response while not all antigens are immunogens. Antigens are usually large proteins or polysaccharides from foreign organisms. Factors like age, health, dose, and route of exposure can influence the immune response. The document also discusses epitopes, haptens, adjuvants, and the relationship of antigens to the host (autoantigens, alloantigens, heteroantigens). It provides details on MHC genes, class I and class II MHC structure and function in antigen processing and presentation to T cells.
This document describes the double immunodiffusion technique, which involves allowing antigens and antibodies to diffuse toward each other in a gel to form visible precipitate lines. It details the historical background, principle, methodology, interpretation of results, applications including pregnancy tests and fungal antigen identification, and recent research using modifications of the technique.
2 antigens, immunogens, epitopes, and haptenstaha244ali
This document discusses key concepts in immunology including antigens, immunogens, epitopes, haptens, innate immunity, and adaptive immunity. It defines antigens as molecules recognized by the immune system and immunogens as antigens that elicit an immune response. Epitopes are the smallest part of an antigen recognized by B and T cell receptors. Haptens are small molecules that require a carrier to induce an immune response. Innate immunity provides the first line of defense using soluble proteins and cells like phagocytes. Adaptive immunity develops over time through T and B cell responses and produces immunological memory.
This is technique used widely for protein separation from a mixture and is very easy and less costly method. Slides cover all essential points about EMSA and it is quite interesting to know that how it detect and separate different proteins and their mobility shift assay.
2D-PAGE is a technique used to separate complex protein mixtures based on isoelectric point and molecular weight. It involves two sequential steps - isoelectric focusing and SDS-PAGE. In isoelectric focusing, proteins are separated based on their isoelectric point in an immobilized pH gradient. They are then separated by SDS-PAGE based on their molecular weight. The separated proteins can then be visualized through staining and identified through mass spectrometry. While useful for proteomic analysis, 2D-PAGE has limitations such as low reproducibility and dynamic range.
Histotypic culture involves growing cell lines in a three-dimensional matrix at high density to form tissue-like structures. Common techniques include using gels, sponges, hollow fibers, spheroids, and rotating chambers to provide a 3D environment that allows cells to organize similarly to how they would in tissues. This allows for the study of processes like drug penetration and cell differentiation that are not possible with traditional 2D cultures. While histotypic cultures provide a model for certain tissue functions, they also face challenges like loss of cell differentiation over time.
The document summarizes epitope prediction and its algorithms. It discusses that epitopes are the portions of antigens responsible for antigen-antibody specificity. There are two main types of epitopes: sequential/continuous epitopes recognized by T helper cells and conformational/discontinuous epitopes recognized by both T and B cells. It then describes several computational algorithms used for predicting B-cell and T-cell epitopes, including Hopp & Woods, Welling's method, Karplus & Schultz parameters, and Kolaskar & Tongaonkar's method. Finally, it lists several databases and servers that can be used for epitope prediction, such as SYFPEITHI, MHCPEP, and EPIM
Immunological techniques are methods used by immunologists to induce, measure, and characterize immune responses. Key techniques described in the document include ELISA, RIA, immunoprecipitation, and western blotting. ELISA uses antibodies to detect antigens and can be used to diagnose conditions like HIV, Lyme disease, and hepatitis. RIA is a sensitive technique that uses radiolabeled antigens or antibodies to detect proteins at very low levels. Immunoprecipitation isolates specific proteins from cell lysates using antibodies, while western blotting separates and identifies proteins by molecular weight.
The document discusses purification of recombinant proteins using affinity tags. It describes immobilized metal affinity chromatography (IMAC) as a widely used method to purify recombinant proteins fused to tags like histidine, GST or MBP. The document outlines the steps involved, including gene amplification, cloning, expression in bacteria or yeast, and purification. It focuses on using histidine tags and nickel-chelate affinity chromatography, noting the advantages of tags for simplifying purification and detection of recombinant proteins.
Introduction
What is cloning?
Why we want to do cloning?
History
Technique of cell cloning
Dolly – the sheep
Species cloned
Why persue animal cloning research?
Conclusion
Introduction
What is cloning?
Why we want to do cloning?
History
Technique of cell cloning
Dolly – the sheep
Species cloned
Why persue animal cloning research?
Conclusion
This document summarizes antigen processing and presentation. It discusses that antigen presenting cells such as macrophages, dendritic cells, and B cells express class II MHC molecules and provide co-stimulatory signals to activate T helper cells. These cells internalize antigens through phagocytosis or endocytosis, degrade them into peptides, and present the peptides bound to class II MHC on their surface. The document also describes the major histocompatibility complex and the roles of class I and class II MHC molecules in antigen presentation to T cells. It outlines the exogenous and endogenous antigen processing pathways, how exogenous antigens are presented by class II MHC and endogenous antigens by class I MHC.
Radioimmunoassay is an in vitro assay technique introduced in 1960 by Berson and Yalow to measure hormone levels in blood plasma. It uses the principles of a competitive binding reaction and measurement of radioactivity. In the assay, a radiolabeled antigen competes with unlabeled antigen from a test sample to bind to antibodies. The amount of radiolabeled antigen bound is inversely proportional to the concentration of unlabeled antigen in the sample. This sensitive and specific technique can detect antigen or antibody levels and has applications in endocrinology, oncology, toxicology and other areas of medical testing.
Immunoassays are chemical tests that use an immunological reaction to detect or quantify a specific substance in a blood or body fluid sample. They work by measuring the formation of antibody-antigen complexes. Immunoassays can be qualitative, detecting only presence or absence, or quantitative, measuring the actual amount present. Common uses include measuring hormones, drugs, proteins, and markers of diseases. Radioimmunoassays were an early type of immunoassay that used radioactive labels on antigens or antibodies to detect complexes via radiation measurement. While sensitive, radioimmunoassays require special handling due to the radioactive materials.
Immunoelectrophoresis is a technique that combines electrophoresis and immunodiffusion to separate and identify antigen components in a mixture. It involves applying an electric current to separate antigens in agar gel wells, then allowing the antigens to diffuse and react with antibodies placed in troughs cut into the gel. This results in the formation of precipitin lines that indicate reactions between individual antigens and antibodies, allowing different antigens to be identified based on the lines' position and shape. Immunoelectrophoresis is used in medical diagnostics to detect abnormal proteins and monitor antigen purity.
Immunological techniques use antigens and antibodies to detect pathogens or their components in patient specimens. Agglutination tests couple antigens or antibodies to particles and look for cross-linking and agglutination. Complement fixation tests measure complement-consuming antibodies by incubating specimens with complement and antigens. Enzyme immunoassays like ELISA use enzyme-linked antibodies to detect antigens and quantify antibodies. Precipitation tests look for visible precipitation of antigen-antibody complexes to detect antigens or antibodies.
This document describes single radial immunodiffusion (RID), a quantitative technique used to determine the concentration of an antigen in a sample. RID involves incorporating specific antibody into an agarose medium with a central well for the antigen sample. The antigen diffuses radially and reacts with the antibody, forming a visible precipitate ring whose diameter relates to the antigen concentration. The technique is simple, cost-effective, and can quantify immunoglobulins, complement components, or other antigens from biological fluids by measuring ring diameters against a standard curve.
Viral vectors are efficient tools for gene delivery due to viruses' ability to transfer DNA into host cells. The document discusses several types of viral vectors, including adenoviral, adeno-associated, retroviral, lentiviral, and baculovirus vectors. It provides details on the structure and genome organization of different viruses used to create these vectors. The document also explains the process of generating recombinant viral vectors by removing unnecessary viral genes and inserting genes of interest. Viral vectors allow for transient or stable gene expression and are useful for both research and clinical applications such as gene therapy and vaccine development.
An antigen is any substance that reacts with lymphocytes, while immunogens generate immune responses. Haptens are small molecules that require coupling to carriers to induce responses. Antibody-antigen binding depends on weak interactions between sites on antibodies and epitopes on antigens. Antibodies are produced with a wide variety of binding sites to recognize different antigenic determinants. Factors like foreignness, size, structure, and route of administration influence a substance's immunogenicity.
There are three major categories of antigenic determinants on immunoglobulin molecules: isotypic, allotypic, and idiotypic determinants. Isotypic determinants distinguish each antibody class and subclass within a species. Allotypic determinants are subtle amino acid differences encoded by different alleles of isotype genes. Idiotypic determinants are generated by the conformation of the amino acid sequences of the heavy- and light-chain variable regions specific for each antigen.
Antibody affinity is a measure of the strength of interaction between an antibody's antigen binding site and its target epitope. It is quantified by the affinity constant Ka, with higher values indicating tighter binding. A high affinity antibody binds its antigen more strongly and for longer than a low affinity antibody. Antibody avidity takes into account not just affinity but also the multivalency of antibodies and antigens, which allows for multiple binding interactions that further strengthen complex formation. High avidity can compensate for low individual binding affinities through cooperative multivalent binding effects.
This document discusses antibody purification methods. It begins with an introduction on the importance of purified antibodies for research and diagnostics. It then covers various sources of antibodies and different purification techniques including precipitation, ion exchange, size exclusion, and affinity chromatography using Protein A/G/L or antigen binding. The document emphasizes that "purified" antibodies can vary in terms of concentration, buffer components, purity level, and potential contaminants. The final buffer an antibody is in and whether it is specific IgG or total IgG can significantly impact its intended use.
The document discusses the nature of antigens and the major histocompatibility complex (MHC). It defines immunogens and antigens, noting that immunogens can trigger an immune response while not all antigens are immunogens. Antigens are usually large proteins or polysaccharides from foreign organisms. Factors like age, health, dose, and route of exposure can influence the immune response. The document also discusses epitopes, haptens, adjuvants, and the relationship of antigens to the host (autoantigens, alloantigens, heteroantigens). It provides details on MHC genes, class I and class II MHC structure and function in antigen processing and presentation to T cells.
This document describes the double immunodiffusion technique, which involves allowing antigens and antibodies to diffuse toward each other in a gel to form visible precipitate lines. It details the historical background, principle, methodology, interpretation of results, applications including pregnancy tests and fungal antigen identification, and recent research using modifications of the technique.
2 antigens, immunogens, epitopes, and haptenstaha244ali
This document discusses key concepts in immunology including antigens, immunogens, epitopes, haptens, innate immunity, and adaptive immunity. It defines antigens as molecules recognized by the immune system and immunogens as antigens that elicit an immune response. Epitopes are the smallest part of an antigen recognized by B and T cell receptors. Haptens are small molecules that require a carrier to induce an immune response. Innate immunity provides the first line of defense using soluble proteins and cells like phagocytes. Adaptive immunity develops over time through T and B cell responses and produces immunological memory.
This is technique used widely for protein separation from a mixture and is very easy and less costly method. Slides cover all essential points about EMSA and it is quite interesting to know that how it detect and separate different proteins and their mobility shift assay.
2D-PAGE is a technique used to separate complex protein mixtures based on isoelectric point and molecular weight. It involves two sequential steps - isoelectric focusing and SDS-PAGE. In isoelectric focusing, proteins are separated based on their isoelectric point in an immobilized pH gradient. They are then separated by SDS-PAGE based on their molecular weight. The separated proteins can then be visualized through staining and identified through mass spectrometry. While useful for proteomic analysis, 2D-PAGE has limitations such as low reproducibility and dynamic range.
Histotypic culture involves growing cell lines in a three-dimensional matrix at high density to form tissue-like structures. Common techniques include using gels, sponges, hollow fibers, spheroids, and rotating chambers to provide a 3D environment that allows cells to organize similarly to how they would in tissues. This allows for the study of processes like drug penetration and cell differentiation that are not possible with traditional 2D cultures. While histotypic cultures provide a model for certain tissue functions, they also face challenges like loss of cell differentiation over time.
The document summarizes epitope prediction and its algorithms. It discusses that epitopes are the portions of antigens responsible for antigen-antibody specificity. There are two main types of epitopes: sequential/continuous epitopes recognized by T helper cells and conformational/discontinuous epitopes recognized by both T and B cells. It then describes several computational algorithms used for predicting B-cell and T-cell epitopes, including Hopp & Woods, Welling's method, Karplus & Schultz parameters, and Kolaskar & Tongaonkar's method. Finally, it lists several databases and servers that can be used for epitope prediction, such as SYFPEITHI, MHCPEP, and EPIM
Immunological techniques are methods used by immunologists to induce, measure, and characterize immune responses. Key techniques described in the document include ELISA, RIA, immunoprecipitation, and western blotting. ELISA uses antibodies to detect antigens and can be used to diagnose conditions like HIV, Lyme disease, and hepatitis. RIA is a sensitive technique that uses radiolabeled antigens or antibodies to detect proteins at very low levels. Immunoprecipitation isolates specific proteins from cell lysates using antibodies, while western blotting separates and identifies proteins by molecular weight.
The document discusses purification of recombinant proteins using affinity tags. It describes immobilized metal affinity chromatography (IMAC) as a widely used method to purify recombinant proteins fused to tags like histidine, GST or MBP. The document outlines the steps involved, including gene amplification, cloning, expression in bacteria or yeast, and purification. It focuses on using histidine tags and nickel-chelate affinity chromatography, noting the advantages of tags for simplifying purification and detection of recombinant proteins.
Introduction
What is cloning?
Why we want to do cloning?
History
Technique of cell cloning
Dolly – the sheep
Species cloned
Why persue animal cloning research?
Conclusion
Introduction
What is cloning?
Why we want to do cloning?
History
Technique of cell cloning
Dolly – the sheep
Species cloned
Why persue animal cloning research?
Conclusion
This document summarizes antigen processing and presentation. It discusses that antigen presenting cells such as macrophages, dendritic cells, and B cells express class II MHC molecules and provide co-stimulatory signals to activate T helper cells. These cells internalize antigens through phagocytosis or endocytosis, degrade them into peptides, and present the peptides bound to class II MHC on their surface. The document also describes the major histocompatibility complex and the roles of class I and class II MHC molecules in antigen presentation to T cells. It outlines the exogenous and endogenous antigen processing pathways, how exogenous antigens are presented by class II MHC and endogenous antigens by class I MHC.
Radioimmunoassay is an in vitro assay technique introduced in 1960 by Berson and Yalow to measure hormone levels in blood plasma. It uses the principles of a competitive binding reaction and measurement of radioactivity. In the assay, a radiolabeled antigen competes with unlabeled antigen from a test sample to bind to antibodies. The amount of radiolabeled antigen bound is inversely proportional to the concentration of unlabeled antigen in the sample. This sensitive and specific technique can detect antigen or antibody levels and has applications in endocrinology, oncology, toxicology and other areas of medical testing.
Immunoassays are chemical tests that use an immunological reaction to detect or quantify a specific substance in a blood or body fluid sample. They work by measuring the formation of antibody-antigen complexes. Immunoassays can be qualitative, detecting only presence or absence, or quantitative, measuring the actual amount present. Common uses include measuring hormones, drugs, proteins, and markers of diseases. Radioimmunoassays were an early type of immunoassay that used radioactive labels on antigens or antibodies to detect complexes via radiation measurement. While sensitive, radioimmunoassays require special handling due to the radioactive materials.
Radioimmunoassay is an assay technique that uses the binding of antigens and antibodies to measure concentrations of substances. It uses a radioactive tracer that competes with the antigen in a sample for binding to a limited number of antibodies. This allows quantification by measuring the bound versus unbound radioactive tracer. RIA has high sensitivity and specificity, and has revolutionized research and clinical practice in areas like endocrinology, pharmacology, and cancer detection.
This document provides an overview of two immunoassay techniques: ELISA and RIA. ELISA (enzyme-linked immunosorbent assay) detects the presence of an antigen or antibody using an enzyme-linked secondary antibody that produces a colored product when reacted with a substrate. RIA (radioimmunoassay) uses a radiolabeled antigen or antibody to compete with unlabeled antigens in a sample, and measures radioactivity to determine antigen concentration. Both techniques rely on the specificity of the antigen-antibody reaction and can be used to detect various targets like hormones, drugs, and infectious diseases.
This document provides an overview of two immunoassay techniques: ELISA and RIA. ELISA (enzyme-linked immunosorbent assay) detects the presence of an antigen or antibody using an enzyme-linked secondary antibody that produces a colored product when reacted with a substrate. RIA (radioimmunoassay) uses a radiolabeled antigen or antibody to compete with unlabeled antigens in a sample, and measures radioactivity to determine antigen concentration. Both techniques rely on the specificity of antigen-antibody binding and can be used to detect various targets like hormones, drugs, and infectious diseases.
The document discusses two types of immunological assays: radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA). RIA uses radioactively labeled antigens or antibodies to detect and quantify antigens or antibodies. It relies on competitive binding and can detect very low concentrations. ELISA uses enzymes to detect antigen-antibody binding and comes in indirect, sandwich, and competitive formats. Both techniques are sensitive and specific methods to detect proteins, hormones, drugs and other molecules through antibody-antigen reactions.
This document discusses immunoassays and two common types - radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA). RIA involves labeling an antigen or antibody with a radioactive material to measure it in a mixture. It is very sensitive but involves radiation hazards. ELISA uses an enzyme-linked antibody or antigen to detect the presence of a substance. It is a plate-based assay that is sensitive, reproducible, and does not use radiation. Both methods are used for applications like disease detection, drug monitoring, and analyzing hormones and metabolites.
Radioimmunoassay (RIA) is a sensitive technique introduced in 1960 that uses radioactive isotopes and antibodies to measure antigens or hormones. It involves competitive binding between radiolabeled and unlabeled antigens for antibodies. Enzyme-linked immunosorbent assay (ELISA) is a common technique introduced in 1971 that uses enzymes to detect and quantify substances like proteins. It can be indirect, sandwich, or competitive based on antigen-antibody binding structure. Both RIA and ELISA are sensitive techniques used to detect substances like hormones, vitamins, drugs, and antigens in clinical medicine and research.
This document discusses various types of immunoassays and their applications. It describes enzyme immunoassays including ELISA and EMIT, fluoroimmunoassays using fluorescent dyes, chemiluminescence immunoassays with luminescent labels, optical immunoassays detecting changes in light reflection, and radioimmunoassays using radioactive antigens. Common applications include detecting drugs, hormones, infectious diseases, and cancer biomarkers in serum, plasma, urine or tissue samples. Immunoassays offer high specificity and sensitivity for quantitative analysis of various analytes in biological specimens.
This document discusses various immunoassay techniques used to detect antigens and antibodies. It describes the basic principles of immunoassays which rely on the specific binding of antigens and antibodies. It then explains different types of immunoassays including ELISA, radioimmunoassay, fluorescence immunoassay, chemiluminescence immunoassay, lateral flow immunoassay, and their applications in detecting various targets like hormones, vitamins, and diagnostic markers.
principle instrumentation and application of capillary electrophoresisAnimikh Ray
Immunochemical assays are based on antibody-antigen interactions in vitro. An immunoglobulin molecule contains two heavy chains and two light chains, each composed of variable and constant domains. Antigen is any foreign molecule that provokes an antibody response. Radioimmunoassay uses radioactive isotopes to detect antigens or antibodies with high sensitivity down to picogram levels. Enzyme-linked immunosorbent assay uses an enzyme label for detection and can be used for both qualitative and quantitative analysis.
What is enzyme-linked immunosorbent assay?
A laboratory technique that uses antibodies linked to enzymes to detect and measure the amount of a substance in a solution, such as serum. The test is done using a solid surface to which the antibodies and other molecules stick.
Theoretical Basis and Optimization of Immunoassay .pptxSahil Nandal
The document provides information about immunoassays including the theoretical basis and optimization of immunoassays. It discusses the principles of immunoassays which rely on the binding of antibodies to antigens to detect or measure specific substances. It describes the various components required for immunoassays including antigens, antibodies, solid supports, detection labels, and detection systems. Furthermore, it explains different types of immunoassays such as ELISA, RIA, CLIA and provides details on their procedures. The document also discusses optimization of immunoassays to improve precision, reproducibility and shelf-life by minimizing background noise and stabilizing protein conjugates.
This document provides an introduction to radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA), including their principles, instrumentation, procedures, applications, advantages and disadvantages. RIA uses radiolabeled substrates to measure trace amounts of antigens or antibodies, while ELISA uses enzyme-labeled substrates to avoid radiation hazards. Both methods rely on antigen-antibody binding and can be used to detect substances like hormones, drugs and proteins. However, RIA requires specialized equipment and handling of radioactive materials. ELISA has become more widely used as it provides sensitive, reproducible detection without radiation safety issues.
1. Radioimmunoassay (RIA) is an immunoassay technique used to detect and quantify substances such as hormones, drugs, and proteins in body fluids using radioactive isotopes. It combines the specificity of antigen-antibody reactions with the sensitivity of radioactive measurements.
2. In RIA, a labeled antigen competes with an unlabeled antigen of interest in a sample for binding to an antibody. The amount of labeled antigen bound is inversely proportional to the amount of unlabeled antigen present.
3. Detection of the bound radioactive labels allows for highly sensitive quantification of the unlabeled antigen in the sample down to picogram levels. RIA is widely used in clinical diagnostics and research.
The following presentation contains helpful information regarding Radioimmunoassay (RIA) and Enzyme-Linked Immunosorbent Assay (ELISA), including their history, introduction, advantages, procedures and applications.
ELISA, principle and method by kk sahuKAUSHAL SAHU
What is ELISA.
Principle.
History.
Types of ELISA method.
1.Direct ELISA.
2.Indirect ELISA.
3.Sandwhich ELISA.
Conclusion.
References.
Antibodies (also known as immunoglobulins abbreviated Ig) are gamma globulin proteins that are found in blood and are used by the immune system to identify and neutralize foreign objects, such as bacteria and viruses.
This document discusses various types of labeled immunoassays, including fluorescent, radioactive, chemiluminescent, and enzyme labels. It describes the key characteristics and procedures for competitive and noncompetitive assays. Specific enzyme immunoassay techniques are covered in detail, such as competitive and noncompetitive ELISA, capture (sandwich) assays, rapid immunoassays, and homogeneous assays. The advantages of enzyme immunoassays include safety compared to radioimmunoassays and the ability to perform assays without expensive instrumentation. Challenges include potential interference from inhibitors or nonspecific binding.
This document discusses immunoassays and two common types - radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA). RIA was developed in the 1950s and involves competition between labeled and unlabeled antigens for binding with antibodies. Radioactivity of the antigen-antibody complex is then measured. ELISA uses an enzyme like alkaline phosphate to visualize antigen-antibody reactions. It has two types - direct ELISA using a double antibody sandwich and indirect ELISA using direct antigen coating. Both assays are used to detect various antigens and antibodies and have applications in clinical diagnosis, food testing, and toxicology.
The document describes the ELISA (enzyme-linked immunosorbent assay) technique. ELISA uses antibodies and enzymes to detect the presence of antigens or antibodies in a liquid sample. It involves coating a plate with capture antibodies, adding the sample and detection antibodies linked to an enzyme, and measuring the enzymatic reaction with a substrate. There are several types of ELISA including direct, indirect, sandwich, and competitive formats. ELISA is a sensitive and widely used technique with applications in diagnosing infections, measuring hormone levels, and screening blood donations.
The document discusses antigen-antibody interactions and various serological techniques used to detect them, including precipitation reactions and agglutination reactions. It describes how antigen and antibody bind through non-covalent interactions, and factors that affect the antigen-antibody reaction like concentration, temperature, and pH. It also summarizes different techniques used to detect antigen-antibody interactions like precipitation, agglutination, Coombs test, and flocculation and the principles behind each method.
Antigen is a substance that induces an immune response through the formation of antibodies or activation of T cells. Antigens can be proteins, polysaccharides, nucleic acids, or lipids. Immunogens are antigens that are capable of inducing an immune response on their own due to their large size, while haptens require a carrier molecule. Antigenicity refers to the ability to bind antibodies, while immunogenicity is the ability to induce an immune response. Factors like molecular size, chemical composition, dose, and route of administration can influence a substance's immunogenicity. Adjuvants are substances that enhance the immune response to an immunogen when used together.
Antibodies, also known as immunoglobulins, are Y-shaped proteins produced by B cells in response to antigens. They are composed of four polypeptide chains - two light chains and two heavy chains arranged in a Y shape. The variable regions at the tips of the Y shape give antibodies their ability to bind to specific antigens. The constant regions allow antibodies to activate different immune functions such as complement activation. There are five major classes of antibodies - IgA, IgD, IgE, IgG, and IgM - which have different structures and roles in the immune response.
This document discusses different types of immunity. It describes innate or natural immunity which individuals are born with and includes species, racial, and individual immunity. Innate immunity acts as the first line of defense and is provided by the skin, mucous membranes, and phagocytic cells. Acquired or adaptive immunity develops after exposure to pathogens and includes both active and passive immunity. Acquired immunity has humoral components involving antibodies and cellular components involving T cells. Herd immunity is also discussed, where a community's immunity protects even unvaccinated individuals when a high percentage of the population is immune.
Edward Jenner in 1798 discovered that exposure to cowpox provided protection against smallpox in humans, laying the foundation for vaccinations. Louis Pasteur further developed vaccines in the late 1800s by using weakened versions of pathogens to provide immunity. In the early 1900s, scientists such as Metchnikoff and von Behring discovered the cellular and humoral components of the immune system, including phagocytic cells and antibodies. The modern field of immunology was established through breakthroughs including the identification of T and B cells in the 1950s and the discovery that antibodies target specific antigens. Recent work in cancer immunotherapy has focused on inhibiting negative immune regulation to stimulate anti-tumor responses.
Hematopoietic stem cells in the bone marrow can differentiate into various blood cell types, including red blood cells, neutrophils, eosinophils, basophils, mast cells, monocytes/macrophages, dendritic cells, B lymphocytes, T lymphocytes, and natural killer cells. These cells play important roles in immunity, such as phagocytosis of pathogens by neutrophils and macrophages, antibody production by B cells, and cytotoxic killing by natural killer and T cells.
The document summarizes the major immune organs in the body. It describes the primary lymphoid organs of bone marrow and thymus, which support the development of immune cells. It also outlines the secondary lymphoid organs of lymph nodes, spleen, and mucosal-associated lymphoid tissue that trap antigens and allow immune cell interaction. Additionally, it discusses the lymphatic system and how blood and lymph vessels connect the immune organs into a coordinated network.
The binding of cosmological structures by massless topological defectsSérgio Sacani
Assuming spherical symmetry and weak field, it is shown that if one solves the Poisson equation or the Einstein field
equations sourced by a topological defect, i.e. a singularity of a very specific form, the result is a localized gravitational
field capable of driving flat rotation (i.e. Keplerian circular orbits at a constant speed for all radii) of test masses on a thin
spherical shell without any underlying mass. Moreover, a large-scale structure which exploits this solution by assembling
concentrically a number of such topological defects can establish a flat stellar or galactic rotation curve, and can also deflect
light in the same manner as an equipotential (isothermal) sphere. Thus, the need for dark matter or modified gravity theory is
mitigated, at least in part.
(June 12, 2024) Webinar: Development of PET theranostics targeting the molecu...Scintica Instrumentation
Targeting Hsp90 and its pathogen Orthologs with Tethered Inhibitors as a Diagnostic and Therapeutic Strategy for cancer and infectious diseases with Dr. Timothy Haystead.
Mending Clothing to Support Sustainable Fashion_CIMaR 2024.pdfSelcen Ozturkcan
Ozturkcan, S., Berndt, A., & Angelakis, A. (2024). Mending clothing to support sustainable fashion. Presented at the 31st Annual Conference by the Consortium for International Marketing Research (CIMaR), 10-13 Jun 2024, University of Gävle, Sweden.
ESA/ACT Science Coffee: Diego Blas - Gravitational wave detection with orbita...Advanced-Concepts-Team
Presentation in the Science Coffee of the Advanced Concepts Team of the European Space Agency on the 07.06.2024.
Speaker: Diego Blas (IFAE/ICREA)
Title: Gravitational wave detection with orbital motion of Moon and artificial
Abstract:
In this talk I will describe some recent ideas to find gravitational waves from supermassive black holes or of primordial origin by studying their secular effect on the orbital motion of the Moon or satellites that are laser ranged.
Or: Beyond linear.
Abstract: Equivariant neural networks are neural networks that incorporate symmetries. The nonlinear activation functions in these networks result in interesting nonlinear equivariant maps between simple representations, and motivate the key player of this talk: piecewise linear representation theory.
Disclaimer: No one is perfect, so please mind that there might be mistakes and typos.
dtubbenhauer@gmail.com
Corrected slides: dtubbenhauer.com/talks.html
Authoring a personal GPT for your research and practice: How we created the Q...Leonel Morgado
Thematic analysis in qualitative research is a time-consuming and systematic task, typically done using teams. Team members must ground their activities on common understandings of the major concepts underlying the thematic analysis, and define criteria for its development. However, conceptual misunderstandings, equivocations, and lack of adherence to criteria are challenges to the quality and speed of this process. Given the distributed and uncertain nature of this process, we wondered if the tasks in thematic analysis could be supported by readily available artificial intelligence chatbots. Our early efforts point to potential benefits: not just saving time in the coding process but better adherence to criteria and grounding, by increasing triangulation between humans and artificial intelligence. This tutorial will provide a description and demonstration of the process we followed, as two academic researchers, to develop a custom ChatGPT to assist with qualitative coding in the thematic data analysis process of immersive learning accounts in a survey of the academic literature: QUAL-E Immersive Learning Thematic Analysis Helper. In the hands-on time, participants will try out QUAL-E and develop their ideas for their own qualitative coding ChatGPT. Participants that have the paid ChatGPT Plus subscription can create a draft of their assistants. The organizers will provide course materials and slide deck that participants will be able to utilize to continue development of their custom GPT. The paid subscription to ChatGPT Plus is not required to participate in this workshop, just for trying out personal GPTs during it.
ESR spectroscopy in liquid food and beverages.pptxPRIYANKA PATEL
With increasing population, people need to rely on packaged food stuffs. Packaging of food materials requires the preservation of food. There are various methods for the treatment of food to preserve them and irradiation treatment of food is one of them. It is the most common and the most harmless method for the food preservation as it does not alter the necessary micronutrients of food materials. Although irradiated food doesn’t cause any harm to the human health but still the quality assessment of food is required to provide consumers with necessary information about the food. ESR spectroscopy is the most sophisticated way to investigate the quality of the food and the free radicals induced during the processing of the food. ESR spin trapping technique is useful for the detection of highly unstable radicals in the food. The antioxidant capability of liquid food and beverages in mainly performed by spin trapping technique.
Current Ms word generated power point presentation covers major details about the micronuclei test. It's significance and assays to conduct it. It is used to detect the micronuclei formation inside the cells of nearly every multicellular organism. It's formation takes place during chromosomal sepration at metaphase.
2. RADIOIMMUNOASSAY
• Radioimmunoassay (RIA) is an in vitro assay that measures the
presence of an antigen with very high sensitivity. Basically any
biological substance for which a specific antibody exists can be
measured in minute concentrations.
• This technique was first developed by S. A. Berson and Rosalyn
Yalow in 1960 to determine levels of insulin-anti-insulin complexes
in diabetics.
Principle:
• Radioimmunoassay (RIA) involves the separation of a protein (from a
mixture) using the specificity of antibody - antigen binding and
quantitation using radioactivity. At increasing concentrations of
unlabeled antigen, an increasing amount of radioactive antigen is
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3. Radioisotopes used in RIA:
1. Beta emitters – H-3, C-14, O-15, N-13 and F-18 (useful for in-
vitro experiments)
2. Gamma emitters – I-125, I-123 (useful for in-vivo imaging)
In all of them I-125 is mostly used because-
a) Shelf life for labelled Ag is long (half life is 60.2 days).
b) Natural constituent of thyroxine and tri-iodothyronine.
c) Easily introduced into peptide molecules, steroids.
d) Gamma radiation emission permits the use of simple radioactivity
counting chamber.
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4. METHODOLOGY OF RIA
Test Contr
ol
Coating of constant
amount of Antibody on
microtitre well against
specific Ag
In test, patient’s serum
and radiolabelled Ag
are add.
In control, only
radiolabelled Ag are
add.
After incubation,
supernatant is removed
and radioactivity of Ag-
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5. ADVANTAGES & DISADVANTAGES
OF RIA
Advantages:
1. Radio immuno assay is very
sensitive technique used to
measure concentrations of
antigen without the need to use
a bioassay. It can measure one
trillionth (10-12) of a gram of
material per milliliter of blood.
2. It is structurally specific as
antigen: antibody reaction are
highly specific.
3. It is indirect method of analysis.
4. It is a saturation analysis as
active reagent added in smaller
Disadvantages:
1. Prolonged reaction time (in days)
as a consequence highly diluted
reagent is used.
2. Radioactive Iodine used in is not a
cheap reagent.
3. Possible health hazards due to
handling of radioisotopes.
4. All the reagents must be added
precisely.
5. Limited assay range.
6. Lack of direct linear relationship
between analyte concentration
and signal response.
7. Difficulty of automation.
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6. APPLICATIONS
1. Narcotics (drug) detection,
2. Blood bank screening for the hepatitis (a highly contagious
condition) virus,
3. Early cancer detection,
4. Measurement of growth hormone levels,
5. Tracking of the leukemia virus,
6. Diagnosis and treatment of peptic ulcers,
7. Research with brain chemicals called neurotransmitter
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7. ROCKET
ELECTROIMMUNODIFFUSION
• Rocket Immunoelectrophoresis, also known as electro-
immunodiffusion, is a simple, quick and reproducible method for
determining the concentration of antigen in an unknown sample.
• This quantitative one dimensional immunoelectrophoresis
method involves a comparison of antigen sample of unknown
concentration with a series of dilutions of a known concentration
of the antigen and requires a monospecific antibody against the
antigen under investigation.
• In this method, antigen migrates from the well through agarose
gel containing antiserum, forming rocket shaped precipitin peaks.
The height of this peak is proportional to the concentration of the
antigen loaded in the corresponding well.
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8. Principle: In Rocket Immunoelectrophoresis, negatively charged antigen
samples are electrophoresed in an agarose gel containing antibody
which is specific to that antigen.
As the antigen moves out of the well and enters the agarose gel, it
combines with the antibody to form immune complex which is visible as
white precipitin arcs.
Because the antigen is migrated through the gel under the influence of
an applied electric current, it moves in one direction.
In initial antigen is in excess over antibody so that no visible
precipitation occurs, as the antigen sample migrates further through the
agarose gel, more antibody molecules are encountered that interact with
the antigen to form immune complex and when this immune complexes
become large enough to be retained within the gel, movement of the
antigen stops.
The area of precipitin has the shape of a rocket and its height is
proportional to the concentration of antigen in the corresponding well.
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10. Applications:
1. Rocket electrophoresis is used mainly for quantitative estimation
of antigen in the serum.
2. The method has been used for quantitation of human serum
proteins before automated methods became available.
3. Determining the concentration of a specific protein in a protein
mixture.
4. In estimation of immunoglobulin protease activity.
5. Studies dealing with antigenic relationships between organisms.
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11. CHEMICAL
IMMUNOFLUORESCENCE/IMMUNOA
SSAY
• Chemiluminescence refers to the emission of light as a result of an
electrical, biochemical, or chemical reaction .
• Some organic compounds become exited when oxidized and emit
light as they revert to the ground state.
• Chemiluminescence immunoassay are most sensitive immunoassays
with detection limits as low as attomole (10-18) or zeptomole (10-21)
level .
• Chemiluminescence can be applied as direct label or
chemiluminescent compound can be used as a substrate for an
enzyme (HRP)-labeled immunoreactant (Ab).
• HRP reacts with Hydrogen peroxide and produces nescent oxygen
which reacts with luminol and produces light.
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12. Most common chemiluminescent compounds are:
Luminol:
• It is the first chemiluminescent label used in immunoassays; it emits
light energy under alkaline conditions in the presence of peroxide
and peroxidase.
• Because peroxidase can serve as the catalyst, assays may use this
enzyme as the label; the chemiluminogenic substrate, luminol, will
produce light that is directly proportional to the amount of
peroxidase present.
Luminol + 2H2O2 + OH- 3-aminophthalate + light
( 425 nm )
Principle:
In the presence of complimentary antigen and antibody, the paratope
of the antibody binds to the epitope of the antigen to form an
antigen-antibody or an immune complex. Estimating the levels of
such immune complex by use of labeled antibodies form the basis of
Peroxidas
e
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14. Applications:
1. Detection of Hormones: insulin, thyroxin, estradiol, testosterone,
progesterone.
2. Detection of Vitamin: vit B12
3. Detection of tumor markers: bone morphogenic protein-2, carcino
embryonic antigen (CEA), alpha fetoprotein (AFP)
4. Detection of human beta chorionic gonadotropin, C-reactive protein and
Tumor necrosis factor
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15. ELISA
The enzyme-linked immunosorbent assay (ELISA) is a commonly used
analytical biochemistry assay, first described by Engvall and Perlmann
in 1971.
The assay uses a solid-phase enzyme immunoassay (EIA) to detect
the presence of a ligand (commonly a protein) in a liquid sample
using antibodies directed against the protein to be measured.
ELISA has been used as a diagnostic tool in medicine, plant
pathology, and biotechnology, as well as a quality control check in
various industries.
Enzymes used in ELISA are HRP (Horse Redish Peroxidase), Alkaline
phosphatase etc.
It is mainly are of 3 types: Direct, Sandwich and competitive.
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16. 1. Indirect ELISA
• It is used for Antibody detection.
• Serum or some other sample containing primary antibody (Ab1) is added to
an antigen-coated microtiter well and allowed to react with the antigen
attached to the well.
• After washing of unbound primary antibody, enzyme (HRP)-conjugated
secondary antibody (Ab2) is added that binds to Ab1.
• Any free Ab2 is again washed away, and a substrate (Peroxide and TMB) for
the enzyme is added. The amount of color produces is measured using a
specialized plate reader.
• Example: HIV detection.
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17. 2. Sandwich ELISA
• Antigen can be detected or measured by a sandwich ELISA.
• In this technique, the antibody is immobilized on a microtiter well.
A sample containing unknown amounts of antigen is allowed to
react with the immobilized antibody.
• After wells washing, a second enzyme (HRP) -linked antibody
(specific to Fc region) is added and allowed to react with the bound
antigen.
• After washing, substrate (peroxide and TMB) is added, and the
colored reaction product is measured.
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18. 3. Competitive ELISA:
• In this technique, antibody is first incubated in solution with a sample
containing antigen, then antigen-antibody mixture is added to an
antigen-coated microtiter well.
• The more antigen present in the initial solution-phase sample, the
less free antibody will be available to bind to the antigen-coated well.
• After washing off the unbound antibody, an enzyme (HRP)-conjugated
Ab2 specific for the Ab1 can be added to determine the amount of
Ab1 bound to the well.
• In the competitive assay, the higher the concentration of antigen in
the original sample, the lower the final signal.
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19. ALLERGEN TEST
Allergy testing can help confirm or rule out allergies and
consequently reduce adverse reactions and limit unnecessary
avoidance and medications.
A positive allergy test indicates a potential readiness to develop an
allergic reaction upon exposure to a specific allergen, but this does
not mean that a clinically significant reaction would necessarily occur.
Increasingly strong allergic tests may correlate with increased disease
activity.
Allergic (Hypersensitivity) Reactions include 4 main types:
1) Immediate (Anaphylactic) (IgE- Mediated) Reaction
2) Cytotoxic Reaction (as incompatible blood transfusion)
3) Immune Complex Reaction (as post- streptococcal GN)
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20. 1. Provocative tests (in vivo test)
A. Skin provocation test:
i. Skin prick test:
• The device used to prick the skin may have a single or multiple heads.
• in a single time several antigens are tested. To avoid cross contamination,
the antigens should be applied at least 2 cm apart and a separate lancet
used for every antigen application.
• A drop of allergen extract is placed on the skin and the needle or lancet is
gently passed through it to penetrate the epidermis without causing any
bleeding. The lancet is held against the skin for 1 second, with equal
pressure applied for each application.
ii. Intra- Dermal Test (IDT):
• Using a hypodermic (insulin) syringe and needle, the skin is held tense and
the needle is inserted just under the dermis, almost parallel to the skin
surface, just far enough to cover the beveled portion.
• Little amount of allergen extract is injected to raise a small bleb.
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22. B. Nasal provocation test:
• Each specific organ or location may have its own pattern of acquiring
IgE sensitized mast cells.
• Specific IgE may be locally produced within the nasal mucosa without
being detectable in skin or blood tests. So, NPT may occasionally be
+ve for a specific Ag while allergic skin tests and serologic IgE
assays related to that Ag are –ve.
• NPT is intended to reproduce pathologic reactions of allergic nasal
mucosa to defined aeroallergens and occupationally relevant
substances under standardized conditions.
• NPT may be a safer alternative to bronchial provocation.
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23. Serological tests (in vitro test)
A. Total IgE:
• Generally elevated in allergic individuals
• Concentrations fluctuate widely.
• It is helpful in diagnosis of Allergic bronchopulmonary aspergillosis
and Atopic dermatitis
B. Allergen specific IgE:
• May be markedly elevated even if total IgE is normal or mildly
elevated, so it may occasionally be used as alternative or
complementary to skin testing.
• Assays are expensive and not readily available for many antigens.
• Helpful in diagnosis of Extensive skin disease or dermographism.
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24. REFERENCES
1. Kuby, J., Goldsby, R. A, Kindt T. J., Osborne B. A. (2013). Immunology 7th
edition, W.H. Freeman and Company, New York.
2. Lyolyard, P. M., Whelan, A., Fanger. M. (2011) Instant Notes in Immunology.
3rd edition. Garland Science Taylor and Francis Group, Newyork
3. A. K. Abbas, A. H. H.Lichtman, S. Pillai. (2017).Molecular and Cellular
Immunity. 9th edition. Elsevier
4. C. A. Janeway, P. Travers, M. Walport, M. J. Shlomchick. (2005). Immunology –
the immune system in health and Diseases. 6th edition. Garland Science
Taylor and Francis Group, Newyork
5. K. Murphy, P. Travers, M. Walport. (2008). Janeway’s Immunology. 7th edition.
Garland Science Taylor and Francis Group, Newyork
6. J. M.Cruse, R. E. Lewis. (2009). Illustrated Dictionary of Immunology. 3rd
edition. CRC Press Taylor and Francis Group, New York.
7. Google
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