Why are antibodies specific for certain antigens?

Answer 1

Antibodies binds to specific region in an antigen. Antibodies recognizes the part of an antigen and binds to specific region. Part of an antigen recognised by the antibody and binds is know as Antigenic Determinant or Epitope.

Antibodies are generated by a sub set of immune cells called B cells. The main receptor for these cells are antibodies, although while they're bound to the surface of the B cell they are called B Cell Receptors (BCRs). While these cells are developing the BCR genes undergo a number of mutations, these mutations define the antigen binding region, which as described above, binds to the antigen. In fact there are so many possible ways the BCR genes can mutate that we can recognize a nearly infinite number of antigens.

Then once your body has encountered an antigen the B cells that have BCRs that can react with the antigen begin to proliferate, and then they start excreting antibodies. After the infection is over, B cells will continue to refine they antigen specificity, that way when they encounter the infection again they can respond with much more specific antibodies and more quickly, this process is called affinity maturation.

Answer 2

Antibodies are specific in the sense that they will only bind to a very specific amino acid sequence.

Amino acids are what make up proteins and antibodies will bind to a protein only if it has a very specific amino acid sequence.

Answer 3

A particular antibody will have a specific configuration of its active site such that it will bind in lock-and-key fashion only to a specific antigen.

Answer 4

Yes, each anitbody is specific to each antigen!

Answer 5

Yes.