Antigen – Antibody reactions detected by precipitation method

Antigen – Antibody reactions detected by precipitation method Prepared by: Irisdavlatova Dilnoza

Plan: 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 One of the easiest of serological tests Soluble AG & Ab interact and form a lattice that develops into a visible precipitate. Rapidly detect pathogenic organisms in a tube by antibody-antigen precipitation.

Ring precipitation test

The steps to perform the test. 1. In a precipitation test tube pour the precipitate serum 2. Carefully add target antigen suspension along inside wall of tube to make a top layer. 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. At the interface of antisera and antigen, preparations А visible precipitate of antibody-antigen complex rapidly forms Remains at the interface The equivalence level of Ab and Ag determines, itself at the interface.

Positive and negative controls used Negative control – nonimmune serum and target Ag. Positive control - specific antiserum and known Ag suspension.

Result 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.

Conclusion This is an Ag-Ab reaction in which the Ag is soluble. When antigens and antibody mixed in the proper proportion, they form large macromolecular complexes called precipitates.

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