Page 978 - Veterinary Immunology, 10th Edition
P. 978
VetBooks.ir Eosinophils
Tissues undergoing type I hypersensitivity reactions
characteristically contain large numbers of eosinophils. These
eosinophils are attracted to sites of mast cell degranulation, where
they release their own contents. Eosinophils are
polymorphonuclear cells, slightly larger than neutrophils or
basophils (12–17 µm in diameter), with cytoplasmic granules that
stain intensely with the red dye eosin (Figs. 29.14, 29.15, and 29.16).
They originate in the bone marrow and spend about 30 minutes
circulating in the bloodstream before migrating into the tissues,
where they have a half-life of about 12 days. The proportion of
eosinophils among the blood leukocytes varies greatly since it is
affected by the presence of parasites. Normal values range from
about 2% in dogs to about 10% in cattle.
FIG. 29.14 The major structural features of an eosinophil.
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