[Acute muramyl dipeptide-induced arthritis in the baboon Papio cynocephalus].

Daily subcutaneous injections of muramyl dipeptide (MDP) for 14 days into yellow baboons (Papio cynocephalus) caused polyarthritis with a prolific fibrinous exudate, but slight synovial lymphocytosis. In contrast, a single injection of bovine serum albumin (BSA) induced only a low-grade synovitis of the ipsilateral knee. When the schedules were combined the histological features suggested an additive effect between the reactions to BSA and to MDP. Larger amounts of MDP diminished the severity of the synovitis but provoked visceral granulomata.