1. IMMUNE DISORDERS CHAPTER 18
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2. Immunological Tests Precipitin
Precipitation
Soluble Ab (IgG or IgM) and Ag
Immunodiffusion
Solid agar medium
Zones of precipitation still seen
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3. Immunodiffusion Plates
Immunoelectrophoresis
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4. Agglutination Test Insoluble Ag plus Ab cause clumping
Easy to perform and read
Direct agglutination
Clumps bacterial cells
Indirect agglutination tests
Place Ab or Ag on artificial particles
Latex spheres
Clay particles
Red blood cell clumping = hemagglutination
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5. Neutralization Test
Ab binds a toxin active site or viral binding site during incubation, neutralizing cell-damaging effects
The mix is placed over a cell layer in culture
Absence of cytotoxic effects in culture indicates correct diagnosis
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6. Complement Fixation Test
Ab/Ag complex competition
Correct diagnosis can create an Ab/Ag complex able to inactivate complement
When a second Ag/Ab complex with RBC is added no lysis of RBC occurs
Incorrect diagnosis creates no Ag/Ab complex
When a second Ag/Ab complex with RBC is added lysis of RBC occurs
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7. Tagged Antibody Tests Immunofluorescence
Fluorescent dyes permit localization as well as diagnosis
Radioimmunoassay
Competition between patient titer and radiolabelled Ag from kit.
Low radioactivity in final sample indicates correct diagnosis or high patient titer
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8. ELISA Tests Enzyme Linked ImmunoSorbent Assay Ab is tagged with enzyme
Enzymatic color reaction is stimulated when productive Ab/Ag binding occurs
Color change indicates correct diagnosis
Copyright © 2012 John Wiley & Sons, Inc. All rights reserved.