Characterization of ST2 transgenic mice with resistance to IL-33

Abstract

IL-33, a member of the IL-1 family, activates MAPK and NF-κB through its receptor ST2L and IL-1RAcP. ST2, a member of the IL-1R superfamily, is a secreted form of ST2 gene products, which has been shown to act as a decoy receptor for IL-33 and to inhibit the IL-33/ST2L/IL-1RAcP signaling pathway. In this work, we generated ST2 transgenic mice. In control mice, intraperitoneal administration of IL-33 caused an increased number of eosinophils in blood and in peritoneal cavity, an increased number of peritoneal MΦ, splenomegaly, accumulation of periodic acid-Schiff-positive material in the lung, and high concentrations of serum IL-5 and IL-13. However, these alterations were hardly detectable in ST2 Tg mice. In peritoneal MΦ from IL-33-stimulated mice, mRNA expression of M2 MΦ marker genes were increased compared with thioglycollate-elicited peritoneal MΦ. The IL-33-stimulation also increased the secretion of IL-6 from MΦ. However, when the IL-33 was preincubated with ST2 prior to its addition to the MΦ cultures, the secretion of IL-6 was attenuated. These data suggest that, though IL-33 induced the Th2-type immune responses and infiltration of M2 type MΦ into the peritoneal cavity, ST2 can downregulate these reactions both in vivo and in vitro. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA.