IFNγ deficient C57BL/6 (H-2b) mice develop collagen induced arthritis with predominant usage of T cell receptor Vβ6 and Vβ8 in arthritic joints

Background: Transgenic deficiency in interferon gamma (IFNgamma) or IFNgamma receptor makes resistant strains of mice bearing H-2(b) or H-2(d) susceptible to collagen induced arthritis ( CIA). Objective: To determine whether the escape from regulation of disease susceptibility at the major histocompatibility complex level involves a new use of autoimmune T cells expressing T cell receptor (TCR) Vbeta that vary from the cell populations previously identified within arthritic joints. Methods: Arthritis was induced by a standard protocol with type II bovine collagen (CII) in complete Freund's adjuvant. Clinical features, histopathology, immunological responses, and TCR profile in arthritic joints in IFNgamma knockout C57BL/6 (B6.IFNgammaKO) mice (H-2(b)) were compared directly with those in DBA/1 mice (H-2(q)). Results: 60-80% of B6.IFNgammaKO mice developed a progressive arthritis with a similar clinical course to classical CIA in DBA/1 mice. The affected joints in B6.IFNgammaKO mice had an erosive form of arthritis with similar features to joint disease in DBA/1 mice. B6.IFNgammaKO mice produced significantly higher levels of IgG2b and IgG1 autoantibodies to murine CII and showed increased proliferative response to CII compared with B6 mice. Comparable levels of interleukin 1beta and tumour necrosis factor a expression were detected in arthritic joints from B6.IFNgammaKO and DBA/1 mice. B6.IFNgammaKO mice used predominantly TCR Vbeta6 and Vbeta8 in arthritic joints. This TCR Vbeta profile is similar to that found in DBA/1 mice with CIA. Conclusions: C57BL/6 mice deficient in IFNy production can develop arthritis that resembles classical CIA. These data suggest that IFNy is a key factor mediating susceptibility to CIA.