EFFECT OF MYCOPLASMA-ARTHRITIDIS SUPERANTIGEN ON ENZYMATICALLY INDUCED ARTHRITIS IN MICE

The objective of this study was to examine the effect of the stimulati on of the immune system with Mycoplasma arthritidis superantigen (MAS) on joint inflammation and cartilage destruction. MAS was administered either alone or combined with a model of degenerative arthritis induc ed by intraarticular injection of collagenase enzyme. Intraperitoneal injection of MAS resulted in activation of peripheral lymphocytes in B ALB/c mice, as shown by a proliferative response of splenocytes isolat ed from MAS-treated animals to IL-2-containing supernatant, Intraperit oneal or intraarticular administration of MAS alone at concentrations maximally activating lymphocytes had no detectable effect on joints. I ntra-articular injection of collagenase resulted in some infiltration of inflammatory cells into the joints, hyperplasia and hypertrophy of synovial lining, pannus formation and surface loss of proteoglycans 7 days following the injection. At 21 days, the animals showed almost to tal loss of cartilage and minimal or no inflammation. Animals receivin g MAS in addition to collagenase treatment showed similar changes in t he joints. These data have demonstrated that activation of the immune system with MAS in pho does not increase joint inflammation or cartila ge degradation in enzymatically induced arthritis.