Page 249 - Veterinary Immunology, 10th Edition

these antigens, makes some improvements, and, by adapting,
VetBooks.ir responds even more effectively when it encounters these organisms

again.
Since the function of the adaptive immune system is to defend

the body against invading microorganisms, it is essential that these
organisms be recognized as soon as they invade the body. The body
must be able to recognize that these are foreign (and dangerous) if
they are to stimulate an immune response. The innate immune

system recognizes only a limited number of PAMPs—those that are
characteristic of major groups of pathogens. The adaptive immune
system, in contrast, uses receptors that can bind and respond to
almost all the foreign macromolecules present in an invading

microorganism. These foreign macromolecules are called antigens.

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