Page 936 - Veterinary Immunology, 10th Edition

VetBooks.ir

FIG. 28.8 Some effects of the immune responses on the stages of
helminth development.

Immunity to Adult Helminths

The expulsion of adult worms from the intestine requires a

coordinated response by multiple cell types under the control of T
cell–derived cytokines. These cells collectively trigger a strong type
2 response that results in mast cell degranulation, acute
inflammation, and ideally, expulsion of the parasites.
The presence of adult worms and their excretory and secretory

products in the intestinal wall will trigger PRRs (Box 28.1). Not a lot
is known about the role of PRRs in resistance to nematodes, but
some helminth products do trigger TLRs and the mannose receptor
is known to bind the excretory/secretory proteins of Trichuris muris.

If the worms cause tissue damage, this will also trigger the release
of alarmins including the three Th2-stimulating cytokines, TSLP, IL-
25, and IL-33 from enterocytes. These cytokines target dendritic
cells and ILC2s. For example, TSLP activates cDC2 dendritic cells.

936