Mouse Ficolin B Has an Ability to Form Complexes with Mannose-Binding Lectin-Associated Serine Proteases and Activate Complement through the Lectin Pathway

Abstract EN

Ficolins are thought to be pathogen-associated-molecular-pattern-(PAMP-) recognition molecules that function to support innate immunity.

Like mannose-binding lectins (MBLs), most mammalian ficolins form complexes with MBL-associated serine proteases (MASPs), leading to complement activation via the lectin pathway.

However, the ability of murine ficolin B, a homologue of human M-ficolin, to perform this function is still controversial.

The results of the present study show that ficolin B in mouse bone marrow is an oligomeric protein.

Ficolin B, pulled down using GlcNAc-agarose, contained very low, but detectable, amounts of MASP-2 and small MBL-associated protein (sMAP) and showed detectable C4-deposition activity on immobilized N-acetylglucosamine.

These biochemical features of ficolin B were confirmed using recombinant mouse ficolin B produced in CHO cells.

Taken together, these results suggest that like other mammalian homologues, murine ficolin B has an ability to exert its function via the lectin pathway.