Done by: Bilal M. Marwa , Abdullah Al- Harby . From the slides of: Dr. Jad AlRab. Application of immunological tests in diagnosis. LECTURE outline. Serological Tests: types of tests where serum is used to measure the amount of antibodies present in it. Serological tests.
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Done by: Bilal M. Marwa, Abdullah Al-Harby.
From the slides of: Dr. JadAlRab
Serological Tests: types of tests where serum is used to measure the amount of antibodies present in it.Serological tests
Antigen – antibody reactions are performed to determine the presence of either the antigen or antibody. (serological tests ).
Either the antigen or the antibody have to be known.
e.g. with a known antigen, such as influenza virus , a test can determine whether antibody to the virus is present or not .Antigen -Antibody Reactions .
In this test, the antigen is in soluble form (solution).
Antibody cross -links antigen molecules to form aggregates (precipitates) in the zone of equivalence: optimal proportion of antigen and antibody.
Precipitation test can be performed in solution or in semi- solid medium (agar).Precipitation test :
For antibody-antigen reaction to form a precipitate that we can see, the amount of antigen and antibody should be the same (optimum concentration).
This happens in the zone of equivalnce.
10 mg a serum sample.antiobdy
3 mg antibody
1 mg antibody
The solution contains
1 mg antigen
Here, we have a plate with 2 holes. We add the antigen in one of them, and the serum in the other, and we allow them to diffuse and form precipitation lines at the points of optimal concentrations.
This method is used to determine whether antigens are related, identical or non –identical.
(see the next slides)4. Double immunodiffusion.
Labeled anti-IgE helps us to measure the amount of reaction
(see next slide)
Enzyme Labelled antibody
Intensity of color correspond to concentration of antibody.
Antigen fixed on slide e.g.
nuclear antigen .
Based on the principle that antigen and antibody reaction activates complement .
Antigen and antibody, one known and the other unknown are mixed.
A measured amount of complement is added .
If antigen-antibody reaction has occurred it will combine “fix” complement.8. Complement fixation
1. Delayed hypersensitivity reactions . cells (red blood cells plus anti-red blood cell antibody) is added.
- delayed skin test.
- patch test.
2. Lymphocyte transformation test .
lymphocyte activation test.
( detect markers by flow cytometry .)Diagnosis of cell-mediated responses: