PPD AND HSP65 INDUCED MONOARTHRITIS INITIATES SPONTANEOUS RECURRENT FLARES IN LEWIS RATS

Objectives-To investigate the time course of a monoarthritis induced w ith the purified protein derivative of tuberculin (PPD) or a recombina nt 65 kDa heat shock protein (rhsp65) in two different strains of sens itised rats. Methods-Wistar and Lewis rats, sensitised with heat kille d Mycobacterium tuberculosis in oil, were challenged intra-articularly with PPD or rhsp65 and monitored for six weeks. Inflammation was asse ssed by joint swelling, histology, and radiographic studies. Results-S ensitised Lewis rats injected with PPD or rhsp65 showed a chronic resp onse with recurrent spontaneous flares, while Wistar rats showed one i nflammatory episode. Conclusions-The Wistar strain response to PPD res embles a transient reactive arthritis, while the response of the Lewis strain mimics the relapsing nature of rheumatoid synovitis, providing an interesting model to determine dominant immunopathogenic mechanism s.