Synovial fibroblasts (RASF) are active drivers of joint destruction in rheumatoid arthritis (RA) through the production of cytokines that maintain the inflammatory process. The Yersinia outer protein M (YopM) is an effector protein of pathogenic Yersinia and is able to enter host cells by membrane penetration and subsequent downregulation of inflammatory responses. Here, we investigated whether YopM has the potential to act as a ‘self-delivering’ immune therapeutic agent by exhibiting a beneficial effect on inflammation and joint destruction …