Suppression of human cartilage proteoglycan synthesis by rheumatoid synovial fluid mononuclear cells activated with mycobacterial 60‐kd heat‐shock protein

Abstract

Objective. To examine whether T cell reactivity toward heat-shock proteins (HSP) contributes to cartilage destruction in rheumatoid arthritis (RA). Methods. An in vitro system was used, in which human cartilage explants were cocultured with hsp60-activated synovial fluid mononuclear cells (SFMC) from patients with RA, and proteoglycan (PG) synthesis was measured. Results. The hsp60-activated SFMC suppressed cartilage PG synthesis. This effect was dependent on the production of interleukin-1 (IL-1) and tumor necrosis factor α (TNFα). Conclusion. Mycobacterial 60-kd heat-shock protein can activate rheumatoid SFMC to suppress human cartilage PG synthesis. This suppression is mediated by IL-1 and TNFα.