Ficolin-2triggersantitumoreffectbyactivatingmacrophagesandCD8+Tcells.

Ficolin-2is an important serum complement lectin. Here, we describe novel findings indicating that serumficolin-2concentrations in multiple tumor patients are significantly lower than those in healthy donors. Administration of exogenousficolin-2or ficolin-A (aficolin-2-like molecule in mouse), with only once, could remarkably inhibit the tumorcellsgrowth in murine tumor models via earlymacrophages, dendriticcells(DCs) andCD8+Tcells, but not CD4+Tcells. Ficolin-A (FCN-A) knockout (KO) mice exhibits significantly increased tumor cell growth.Ficolin-2induces macrophage activation, promotes M1 polarization and facilitates proliferation and antigen-specific cytotoxicity ofCD8+Tcells.Ficolin-2binds to Toll-like receptor 4 (TLR4) onmacrophagesand DCs and promotes their antigen-presenting abilities toCD8+Tcells. Our findings provide a new therapeutic strategy for tumors based on the triggering of immune-mediatedantitumoreffectbyficolin-2.