Amelioration of intestinal colitis by macrophage migration inhibitory factor isolated from intestinal parasites through Toll-like receptor 2

Summary In a previous study, we cloned type II MIFs (As-MIF) from Anisakis simplex 3rd stage larva and expressed a recombinant protein that suppressed allergic airway inflammation via regulatory T (CD4+CD25+Foxp3+ T; Treg)-cell recruitment. In this study, in an effort to evaluate the function of rAs-MIF on another immune disease, we induced intestinal inflammation in mice using dextran sodium sulphate (DSS) with or without the application of rAs-MIF treatment to the mice. As a consequence, weight losses were recovered, and the value of disease activity index (DAI) was reduced by rAs-MIF treatment during the experimental period. The levels of TGF-β and IL-10 in the spleens and mesenteric lymph nodes (MLN) from the rAs-MIF-treated mice were higher, but the levels of IFN-γ, IL-6 and IL-13 were lower than those of the mice treated with DSS but not with rAs-MIF. Additionally, the Treg cells observed were greatly increased in the MLNs of the rAs-MIF-treated mice than those of mice not treated with rAs-MIF. The results of our in vitro experiments showed that the elevated IL-10 production induced by rAs-MIF was generated via toll-like receptor 2. In conclusion, rAs-MIF appears to ameliorate DSS-induced colitis and may prove useful as a therapeutic agent for the treatment of intestinal inflammatory disease.