Ficolins are members of the collectin family of proteins which recognize PAMP on microbial surfaces. Human and murine ficolins differ in many aspects. Mouse has two ficolin forms, termed ficolin-A and -B. Mouse ficolin-A is the plasma protein, highly expressed in liver and spleen. Mouse ficolin-B is expressed in spleen, bone marrow, and peritoneal macrophages. It is thought to facilitate phagocytosis and is involved in the activation of complement pathways. Ficolin B is a glycosylated protein which causes it to run on a WB at larger than the predicted molecular weight of 34 kD.