Antigen – Antibody reactions detected by precipitation method Prepared by: Irisdavlatova Dilnoza
Plan: l l l State the purpose of the test. The steps to perform the test. Name of components. Mechanism of reaction. Positive and negative controls used. Results
Precipitation Serological Tests l One of the easiest of serological tests l Soluble AG & Ab interact and form a lattice that develops into a visible precipitate. l Rapidly detect pathogenic organisms in a tube by antibody-antigen precipitation.
Ring precipitation test
The steps to perform the test. l 1. In a precipitation test tube pour the precipitate serum l 2. Carefully add target antigen suspension along inside wall of tube to make a top layer. l 3. Observe interface for reaction. Do not disturb tube.
Name of components – – – Components: Material from patient (unknown Ag). Specific precipitation serum – (known Ab). Used: For express-diagnosis of infection disease (ex. Anthrax)
Mechanism of reaction. l At the interface of antisera and antigen, preparations l А visible precipitate of antibody-antigen complex rapidly forms l Remains at the interface l The equivalence level of Ab and Ag determines, itself at the interface.
Positive and negative controls used l Negative control – nonimmune serum and target Ag. l Positive control - specific antiserum and known Ag suspension.
Result l Positive reaction - at the interface of the two layers there is a muddy ring (precipitate). This reaction is often called a “ring precipitation”. This assay requires full transparency of antigen and antibody, otherwise results of reaction will be not clear. l
Conclusion l This is an Ag-Ab reaction in which the Ag is soluble. l When antigens and antibody mixed in the proper proportion, they form large macromolecular complexes called precipitates.
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Antigen_Antibody_reactions.ppt