MMG301 1st Edition Lecture 39Outline of Last Lecture I. Growth methodsII. Bio safety levelIII. Sources for specimensIV. Testing methodsOutline of Current Lecture II. Agglutination III. Fluorescent antibodiesIV. ELISACurrent Lecture-Direct agglutination: soluble antibodies cause clumping of antigens that are on the surface of a particle or cell-Examples: agglutination of blood cells in blood typing (hemagglutination) or bacterial cells (serotyping)Indirect (Passive) agglutination – antigens or antibodies are chemically coupled to particles such as latex beads – latex agglutination assay-Example: latex beads coated with antibodies to Protein A – a protein found only on the surface of Staphylococcus aureus cells; very specific and rapid assay for presence of this bacterium -Fluorescent antibodies: purified antibodies that recognize specific antigens are chemically modified with fluorescent dyes-Often used to examine for a pathogen in a complex clinical sample-Antibodies are used that bind to certain specific bacterial cells or viruses-Samples are often visualized by fluorescence microscopy-Enzyme-Linked Immunosorbent Assays (ELISA) can be used to detect antigens or antibodies in clinical specimensThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.-Various enzymes are chemically attached to antibodies-Enzyme catalyze reactions that lead to readily visible color changes to allow for rapid and sensitive detection of antigens-1. Direct ELISA: purified antibodies that recognize an antigen are linked with enzymes that catalyze colored product-producing reactions-Used for detecting antigen in clinical samples-2. Indirect ELISA: -Purified antigen is absorbed to microtiter plate-Patient’s serum (containing antibodies to that antigen) is added. -Then anti-antibodies linked to an enzyme are added-Important concept: antibodies that recognize and bind antibodies from another animal can be used for this assay (for example, you can buy commercially prepared anti-human IgG antibodies produced in
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