Page 33 - Veterinary Immunology, 10th Edition

their destruction by defensive cells. Some of these molecules are
VetBooks.ir present in normal tissues all the time, while others are produced in

response to the presence of bacteria, viruses or cell and tissue
damage.

FIG. 1.3 The innate immune system consists of a collection of
subsystems. They can be divided into the cellular mechanisms
where populations of specialized cells detect, eat, and kill invaders;
and the humoral mechanisms where diverse soluble molecules bind
and kill the invaders.

Other innate subsystems rely on rapid cellular responses to
invasion. Thus the body employs sentinel cells that can detect
invading bacteria and viruses. Sentinel cells recruit other cells,

called leukocytes, that converge on the invaders and destroy them
in the process we call inflammation. Inflammation is central to the
innate defenses of the animal body. Some of the cells involved in
inflammation may also help repair damaged tissues once the

invading microbes have been destroyed. It is the presence of a

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