The body produces substances known as antibodies to
fight disease-producing agents. Antibody production is a relatively slow
process. First of all, the body cells must recognize the invading agent as
"foreign" -- an antigen -- and then produce an antibody that is exactly right to
immobilize the protein invader. Finally, the blood cells must go into full scale
production of this specific antibody. An antibody is specific against "a
particle" type of germ. For example: diphtheria antibodies will not be
effective
against scarlet fever antigen.
