A soluble form of the CSF-1 receptor contributes to the inhibition of inflammation in a teleost fish.

We previously reported on the identification of a novel soluble form of the CSF-1 receptor (sCSF-1R) in goldfish that induced dose-dependent down-regulation of macrophage proliferation. Herein, we report that sCSF-1R has a role beyond macrophage development, which extends into the control of cellular antimicrobial inflammatory responses in this lower vertebrate. Using an in vivo model of self-resolving peritonitis coupled to in vitro characterization of sCSF-1R activity, we show that sCSF-1R plays a role in the inhibition of inflammation which follows an initial acute phase of innate antimicrobial responses within an inflammatory site.