Power in Numbers
Your blood contains upwards
of 100,000,000 different types of antibodies. Each type binds to a different
target molecule. Remarkably, all of these antibodies are created before
they ever see a virus or bacterium. You don't make a special antibody
when a virus or bacterium infects your body. Instead, all of your antibodies
are pre-fabricated, lying in wait until a virus or bacterium attacks.
There are so many different kinds of antibodies that one or two are
bound to be the right ones to fight the infection.
This amazingly huge collection
of antibodies is created by recombination of genes in lymphocytes, the
blood cells that make antibodies. Each lymphocyte creates a different
type of antibody, based on how it has recombined its antibody genes.
When an antibody encounters a virus or bacterium, the appropriate lymphocytes
will multiply, flooding the blood with the particular antibodies needed
to battle the invader. These lymphocytes may also make small adjustments
on the antibodies they produce, tailoring their antibodies to bind more
tightly and more specifically.
In the picture you may see
how antibody bind to antigen. There molecular surfaceof the immunoglobin
G and their antigen ( lysozym
) has been computed.