TLR2-dependent amelioration of allergic airway inflammation by parasitic nematode type II MIF in mice.

In our previous studies, the recombinant type II macrophage migration inhibitory factor homologue (rAs-MIF) secreted from Anisakis simplex suppressed experimental inflammation mouse model through IL-10 production and CD4(+)CD25(+)Foxp3(+) T-cell recruitment. Also, TLR2 gene expression was significantly increased following rAs-MIF treatment. To know the relation between TLR2 and amelioration mechanisms of rAs-MIF, we induced allergic airway inflammation by ovalbumin and alum with or without rAs-MIF under TLR2 blocking systems [anti-TLR2-specific antibody (α-mTLR2 Ab) treatment and using TLR2 knockout mice]. As a result, the amelioration effects of rAs-MIF in allergic airway inflammation model (diminished inflammation and Th2 response in the lung, increased IL-10 secretion, CD4(+)CD25(+)Foxp3(+) T-cell recruitment) were diminished under two of the TLR2 blocking model. The expression of TLR2 on the surface of lung epithelial cell was significantly elevated by rAs-MIF treatment or Pam3CSK (TLR2-specific agonist) treatment, but they might have some competition effect on the elevation of TLR2 expression. In addition, the elevation of IL-10 gene expression by rAs-MIF treatment was significantly inhibited by α-mTLR2 Ab or Pam3CSK pretreatment. In conclusion, anti-inflammatory effects of the rAs-MIF on OVA-induced allergic airway inflammation might be closely related to TLR2.