Monocytes that have ingested Yersinia enterocolitica serotype O : 3 acquire enhanced capacity to bind to nonstimulated vascular endothelial cells viaP-selectin

Reactive arthritis is usually a self-limiting polyarthritis which develops after certain gastrointestinal or urogenital infections. Microbial antigens found in the inflamed joints are thought to play a key role in the develop ment of this disease. Pt is not known how antigens of the pathogenic organi sms migrate from the mucosal tissues into the joints. The data presented he re show that mononuclear phagocytes which mediate the dissemination of seve ral intracellular pathogens acquire an enhanced capacity to bind to nonstim ulated vascular endothelial cells after phagocytosis of Yersinia enterocoli tica O:3, one of the causative organisms of reactive arthritis. The increas ed binding to previously nonstimulated endothelial cells was mediated by P- selectin, whose translocation to the endothelial cell surface was induced b y monocytes with intracellular Yersinia bacteria. These results suggest tha t mononuclear phagocytes may be responsible for the dissemination of bacter ial antigens and the initiation of the joint inflammation in reactive arthr itis.