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Capture and detection - difference between the two (Apr/10/2005 )


Immunology is not my degree, but i need to know the difference between Antibody capture ELISA and detection ELISA, can anyone help please?




I'm not quite sure what exactly you mean, but maybe I can help you a little anyway...

basically, there are two different kinds of ELISA: antibody capture and antigen capture ELISA

for antibody capture ELISA, you immobilise definite amounts of your antigen on a ELISA plate, then incubate it with serum or any other liquid containing antibodies, which then are captured by the antigen. for detection of your bound antibodies, usually anti-Ig antibodies are used. this ELISA will give you information if and how much antibodies to a given antigen are in a solution and is therefore used in serology (person A has more antibodies to protein X in the serum than person Y, or monoclonal B-cell line A produces more antibodies to protein X than monoclonal cell line B ).

for antigen capture ELISA, you immobilise a antibody to the antigen you want to detect on a ELISA plate, incubate this with a solution containing your antigen. so the bound "capture antibody" will capture the antigen. detection of bound antigen is done by adding another antibody "detection antibody", that recognises another part of the antigen bound to the capture antibody. so this type of ELISA will give you information how much of a given antigen is there in your solution, and is therefore used in cytokine ELISAs, for example. (after stimulation with LPS, there were 30.000 pg/ml interferon-gamma in the medium of my cell culture, while incubation with PBS only yielded 20 pg/ml)
You can have a look on the principle of ELISA in any good textbook in molecular biology/immunology/microbiology or at :