Page 979 - Veterinary Immunology, 10th Edition

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FIG. 29.15 Photomicrographs of peripheral blood eosinophils from
a horse, a cat, and a dog. Each cell is about 12 µm in diameter.
Giemsa stain. (Courtesy Dr. M.C. Johnson.)

FIG. 29.16 A transmission electron micrograph of a rabbit
eosinophil. (Courtesy Dr. S. Linthicum.)

Eosinophil Activation

Eosinophils arise from bone marrow stem cells under the influence
of IL-3, IL-5, and GM-CSF (Fig. 29.17). The great majority of the

body's eosinophils are located in the intestine. Both Th2 cells and
mast cells produce IL-5 and the chemokines known as eotaxins that
stimulate the release of eosinophils from the bone marrow. IL-25,
IL-33, and TSLP all induce IL-5 production. Thus Th2 cells mobilize

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