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2. Serology. A science that attempts to detect signs of infection in a patient's serum such as Ab for a specific microbeSerological tests based on Abs specifically binding to Ag. Ag of known identity will react with Ab in an unknown serum sample.Known Ab can be used to detect Ag in serumAg-Ab re
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1. Serological reactions in Microbiology Tatyana Ivakhnyuk
2. 2 Serology A science that attempts to detect signs of infection in a patient’s serum such as Ab for a specific microbe
Serological tests based on Abs specifically binding to Ag.
Ag of known identity will react with Ab in an unknown serum sample.
Known Ab can be used to detect Ag in serum
Ag-Ab reactions are visible by clumps, precipitates, color changes or release of radioactivity.
The most effective tests have high specificity and sensitivity.
3. 3 Types of serological tests Agglutination tests
Precipitation tests
Immunoelectrophoresis
Western blot tests
Complement fixation tests
Immunofluorescence testing
Immunoassays
4. Characteristics of serological reactions
Reactants used
Visible and invisible reactions
Determination of titer
Hapten reactions
Serology
5. 5 Agglutination tests – Ab cross-links whole cell Ag, forming complexes that settle out and from visible clumps in the test chamber
blood type, some bacterial & viral diseases
6. Agglutination
General reaction
Example in Widal test
Tube and slide agglutinations
Passive agglutination
Hemagglutination
Coombs test
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13. Precipitation Tests
One of the easiest of serological tests
Relies on fact that antigens and antibody mixed in the proper proportion form large macromolecular complexes called precipitates
Correct proportions are important to create precipitation
Two techniques determine optimal antibody and antigen concentrations
Immunodiffusion
Immunelectrophoresis
14. Ring Precipitation Test Components:
Material from patient (unknown Ag).
Specific precipitation serum – (known Ab).
Used:
For express-diagnosis of infection disease (ex. Anthrax)
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15. Immune Testing
16. Immune Testing
17. Complement fixation
Components of the CFT:
1. Serum from patient (unknown Ab).
2. Specific antigen (known Ag).
3. Complement.
4. Erythrocytes from sheep.
5. Hemolytic serum (in this serum present Ab
against Erythrocytes from sheep).
18. Complement fixation: Principle 18
19. 19 Immunofluorescence testing
uses fluorescent Ab either directly or indirectly to visualize cells or cell aggregates that have reacted with the FAbs
20. Immuno-fluorescence Principle
Use fluorescein isothiocyanate labeled-immunoglobulin to detect antigens or antibodies according to test systems
Requires a fluorescent microscope
Examples
Herpes virus IgM
Dengue virus
Rabies virus
Scrub and murine typhus Photos public domainPhotos public domain
21. Types of immuno-fluorescence Direct immuno-fluorescence
Used to detect antigen
Indirect and sandwich immuno-fluorescence
Antigen detection
Antibody detection Graphic self preparedGraphic self prepared
23. ELISA Enzyme-linked immunosorbent assay (ELISA) can detect unknown Ag or Ab by direct or indirect means. A positive result is visualized when a colored product is released by an enzyme-substrate reaction.
ELISAs
Stands for enzyme-linked immunosorbent assay
Uses an enzyme as the label
Reaction of the enzyme with its substrate produces a colored product indicative of a positive test
Most common form of ELISA is used to detect the presence of antibodies in serum
24. ELISA
25. ELISA – general skim
26. 26 Immunoelectrophoresis – migration of serum proteins in gel is combined with precipitation by Ab
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28. 28 Western blot test – separates Ag into bands. After the gel is affixed to a blotter, it is reacted with a test specimen and developed by radioactivity or with dyes
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