The Dynamics of Articular Leukocyte Trafficking and the Immune Response to Self Heat-Shock Protein 65 Influence Arthritis Susceptibility

INTRODUCTION: Adjuvant arthritis (AA) shares several features with human rheumatoid arthritis, and it can be induced in the Lewis (LEW) rat but not the Wistar Kyoto (WKY) rat (both RT.1(l)) by immunization with heat-killed Mycobacterium tuberculosis (Mtb). We set out to unravel the mechanisms underlying the differential susceptibility to AA of these MHC-compatible rat strains. MATERIALS AND METHODS: We compared the levels of T-cell proliferative and cytokine response to the immunoregulatory self (rat) hsp65 (Rhsp65) after an arthritogenic (Mtb) challenge and the kinetics of migration of adoptively transferred, (111)Indium-labeled, Mtb-primed leukocytes into the hind paw joints of recipient rats. RESULTS AND DISCUSSION: The WKY rats raised a significantly higher level of T-cell proliferative response coupled with a temporally opposite cytokine profile against the disease-regulating Rhsp65 compared to that of LEW rats. Moreover, the arthritogenic leukocytes accumulated into the joints of WKY rats at significantly lower numbers than that in LEW rats. CONCLUSIONS: These results offer novel insights into the immune events influencing the pathogenesis of autoimmune arthritis.