Affinity of antibodies

[siwi]

Hi everybody!

I recently heard from an assistant at the university that the affinity of built antibodies is dependent on the concentration of the presented antigen. So that it is possible if you treat for example a mouse with three different doses of an antigen that the mouse build more antibodies under the small dose than under the other...

 

I just wanted to look in the literature for some hints to this subject, unfortunately, I don't know the correct scientific expression for this phenomenon. Maybe someone of you could help me?

 

Thanks very much!

 

 

[BabcockHall]

It seems to me that you are asking two very different questions. The way a chemist might define affinity (probably by the magnitude of the association constant) is independent of the concentration of the antigen. However, in your second sentence you are discussing the amount of the antibody that is produced, which is something different. On the latter question I don't know enough about immunochemistry to offer a strong opinion, but I am a skeptical of the possible claim that a smaller amount of antigen would produce a greater amount of antibody.

Edited September 23, 2015 by BabcockHall

[siwi]

Sorry this is true, the second sentence is a way too puzzling...but thanks a lot for your answer!

[BabcockHall]

The free antibody and the the free antigen can combine to form a complex:

 

Antibody + antigen <==> antibody•antigen

 

The larger the association constant, the greater the probability of finding the antibody and antigen together as a complex, as opposed to each one being a free chemical species. The association constant measures how strongly the antibody and antigen are bound together. The double-headed arrow in the equation above is intended to convey the fact that this process is reversible.