Affinity, what is it?

SLRCmg slrcmg at
Thu Nov 16 19:35:07 EST 1995

Troels Wind wrote:

>Heres a little theoretical question for you immunologists. Imagine, that
>monoclonal Abs towards the SAME antigen are available. For simplicity,
>assume the antigen is monomeric, i.e. no epitopes exist in duplicate.

>If one uses these two Abs in ELISA towards the antigen under the same 
>conditions (same coating, same concentration of Ab, same detection Abs
>and one of them gives a higher signal than the other, is it then fair to
>that it has a higher affinity than the other? If not, then WHAT is higher
>better, yhat results in the better ELISA-signals?

>I would really appreciate any input on this!

If your detection antibody (Goat anti-mouse AP conjugate, e.g.) binds
better to one of the two antibodies, that antibody will give you a higher
signal in ELISA, all other things being equal.  Just a question of more AP
molecules per molecule of monoclonal.

Hope this helps.


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