Influence of arginine deimination on antigenicity of fibrinogen

Autoreactivity is controlled at various steps by numerous mechanisms and is a key to understanding and treating autoimmune disease. Recently, an antibody against deiminated fibrinogen (DI-FBG) was detected in patients with rheumatoid arthritis (RA) with high specificity and sensitivity. DI-FBG converted enzymically by peptidyl arginine deiminase, was also detected in synovial membrane. In the present study, we investigated whether antibody to DI-FBG is produced in mice immunized with DI-FBG. Mice were immunized with DI-FBG in the presence or absence of adjuvant. Production of the specific antibody was only induced with adjuvant. The resulting antibody was specific for DI-FBG and did not react with intact/native fibrinogen. Furthermore, it recognized deiminated human fibrinogen and cyclic citrullinated peptide (CCP). These results suggested that mouse fibrinogen acquires antigenicity in mice through deimination and therefore, autoantibody such as that detected in RA patients specifically may be induced.