Page 980 - Veterinary Immunology, 10th Edition

eosinophils while promoting IgE responses. These eosinophils are
VetBooks.ir attracted to sites of mast cell degranulation by eotaxins, histamine,

and its breakdown product imidiazole acetic acid, leukotriene B , 5-
4
hydroxytryptamine (5-HT), and by PAF. Eosinophils are especially
attracted by CXCL8 (IL-8) complexed to IgA. Some allergens
directly activate eosinophils, stimulating their chemotaxis and

upregulating CR3 expression. The mobilization and activation of
eosinophils enhances their ability to kill parasites and supports the
belief that the major function of the IgE-mediated responses is the
generation of type 2 responses resulting in the control of helminth
parasites (Chapter 28). Activated eosinophils express MHC class II

molecules and can serve as antigen-presenting cells.

FIG. 29.17 The regulation of eosinophil mobilization, chemotaxis,
and activation.

Eosinophil Degranulation and Mediators

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