An essential role for TH2-type responses in limiting acute tissue damage during experimental helminth infection.

Helminths induce potent T helper 2 (TH2)-type immune responses that can mediate worm expulsion, but the role of this response in controlling the acute tissue damage caused by migrating multicellular parasites through vital tissues remains uncertain. We used a helminth infection model in which parasitic nematode larvae migrate transiently through the lung, resulting in hemorrhage and inflammation. We found that IL-17 initially contributed to inflammation and lung damage, whereas subsequent IL-4 receptor (IL-4R) signaling reduced elevations in IL-17 mRNA levels, enhanced the expression of insulin-like growth factor 1 (IGF-1) and IL-10 and stimulated the development of M2 macrophages, all of which contributed to the rapid resolution of tissue damage. These studies indicate an essential role for TH2-type immune responses in mediating acute wound healing during helminth infection.