Page 129 - Veterinary Immunology, 10th Edition

Depending upon the nature of the invader, these cells may include
VetBooks.ir dendritic cells, mast cells, eosinophils, neutrophils, macrophages,

and innate lymphoid cells. The most significant of these, at least in
the early stages of inflammation, are neutrophils, large numbers of

which are attracted to sites of invasion where they kill and eat the
invaders. This process is called phagocytosis (Greek for “eating by
cells”). The prime purpose of the inflammatory process is to ensure
that phagocytic cells intercept and destroy invading microbes as

rapidly and efficiently as possible.
Defensive cells circulate in the bloodstream where they are
collectively called leukocytes (white blood cells) (Fig. 5.1). All
leukocytes originate from bone marrow (myeloid) stem cells, and

all help defend the body. Two types of leukocytes specialize in
killing and eating invading microorganisms. These, called
neutrophils and macrophages, originate from a common stem cell
but look very different and have different, but complementary,

functions. Neutrophils respond and eat invading organisms rapidly
but are incapable of sustained phagocytic effort. Macrophages, in
contrast, move more slowly but are highly effective phagocytes and
are capable of repeated phagocytosis. In this chapter, we review the

properties of neutrophils and their role in inflammation and innate
immunity. We will look at macrophages in the next chapter.

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