Immunology - Affinity Maturation

[MushyBook]

Hi All,

Just a quick question regarding affinity maturation in response to an antigen. If the B cells are undergoing hyper mutation to produced the appropriate antibody for the antigen of the invader, do they not produce a huge number of wasted antibodies that will remain in the body ? As I understand it, (I may be wrong) they have to experiment with mutated antibodies to fit with the antigen, with only a tiny number of antibodies fit for purpose. I can't see how the body deals with all the wasted antibodies produced in the process ?

[Elite Engineer]

Your body has millions upon millions of random, sequenced antibodies for completely random and different antigens...there are technically tons of "wasted antibodies" that your body needs to keep around fopr

 

identifiying any kind of foriegn antigen.

 

-there not really wasted, just longterm storage for potential use...the more antibodies you have with more random sequences, the better you have at recognizing a foriegn antigen and dealing with it.

[MushyBook]

Thanks for that, but I still think there would be some sort of problem with them. Would a biomolecule in such massive excess not be toxic in some way, it would need to be 'mopped up'. Do these randomly generated sequences wait around in storage ? I thought that it was only the ones that were activated that were kept for later use ?

[CharonY]

The amounts are not precisely massive relative to other proteins in blood. About 60-80% at any given point is albumin, for example. There is also a relatively high turnover rate of proteins in blood, featuring protein digestion and degradation. Also the lifetime of most B-cells is in the order of a few weeks (and in some cases, days).

[MushyBook]

That would explain it, thank you. Is the blood a constantly changing environment then, protein concentrations varying from week to week ? How does this manage to fit into the homeostasis and the constant internal environment ? I understand of coure, that it's not going to be a perfect constant, but does the body have much trouble regulating the blood to stay at a reasonably constant, stable state ?

[CharonY]

Overall concentration does not vary much as release of albumin regulates the osmotic content in blood. However the content changes on a continuous basis. It is wrong to imagine the organism or blood in a static homeostatic situation, some parameters are kept somewhat in an equilbrium but specifics (such as protein expression and secretion) changes constantly depending on many internal and external factors.