Posts Tagged ‘just’
Last Updated on Friday, 2 July 2010 10:09 Written by Administrator Friday, 2 July 2010 10:09
Question by teck kim: in ELISA, why the assay need secondary antibody labeled, why no just label the primary antibody?
Answer by Isopropyl_Dog
antibodies have two sides: a constant region and a variable region. So the primary antibody has a variable region that specifically binds to the antigen of interest… this primary antibody can be made naturally by the immune system of an organism. If a person is exposed to antigen X, the natural process in his body will create anti-X antibodies. So then we could take a sample of his blood and collect the anti-X antibodies (with affinity chromatography this is easy), purify them and use them in an ELISA to detect antigen X. Unfortunately the natural process does not label the antibodies… thats why we need secondary antibodies.
The secondary antibody specifically binds to the constant region of the primary antibody (all the primary antibodies will have similar constant regions) and has a detectable probe. So you can use the same secondary antibody with lots of different primary antibodies.
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Last Updated on Saturday, 12 June 2010 07:05 Written by Administrator Saturday, 12 June 2010 07:05
Question by fingerseven11: The ELISA (immunoassay) test can be used to test for LSD. I’m just wondering if anyone can tell me HOW?
I don’t see how an IMMUNE type test could test for lsd?
Answer by Tim
Immunoassay tests test for the presence of antigens in the blood. I’d guess that lsd produces some kind of an immune response in the body, resulting in lsd-specific antigens floating around in the blood. That would ring up a “positive” response in an immunoassay.
Just a guess!
What do you think? Answer below!