TNF and Arthritis: In the course of our preliminary studies in the rat adjuvant-induced arthritis (AA) model of human RA [8-13], we observed that the levels of TNFα produced by the arthritogenic epitope of mycobacterial heat-shock protein 65 (Bhsp65) [10-12,14] were highest in the recovery phase of the disease compared to that at the onset or the peak phase of AA.