FGL2 is a secreted protein that is similar to the beta- and gamma-chains of fibrinogen. The carboxyl-terminus of the encoded protein consists of the fibrinogen-related domains (FRED). The encoded protein forms a tetrameric complex which is stabilized by interchain disulfide bonds. It may play a role in physiologic functions at mucosal sites. It is constitutively expressed in cytotoxic T-cells. Lack of expression in other lymphoid- and nonlymphoid-derived cell lines suggested that expression of FGL2 may be restricted to lymphocytes. FGL2 is induced via a mechanism involving IFNG and components of the IFNG signaling pathway, including STAT1 and IRF1.