Figure 5

Expression of TNF receptor associated factor (TRAF)6, caspase-1 and interleukin-1β (IL-1β) in splenocytes of interferon-γ receptor knock-out (IFN-γR KO) mice (KO) and wild-type mice (WT), both naive and immunised with collagen type II in complete Freund's adjuvant (CII/CFA) (day 21 after immunisation). Splenocyte suspensions of three mice within each group were pooled and lysed. Total protein (30 μg) was loaded for electrophoresis and blotted. The blotting membrane was incubated with anti-TRAF6 or anti-TRAF2 antibody (a), anti-caspase-1 antibody (b) and anti-IL-1β antibody (c). (a) Degradation of TRAF6 in CII/CFA-immunised IFN-γR KO mice: there is unaltered expression of TRAF2, demonstrating that TRAF6 degradation is not caused by an overall higher protease activity in mutant mice. (b) Differential expression of the caspase-1 isoforms: inactive pro-caspase-1, intermediate caspase-1 form and the active 20 kDa form (p20). (c) Inactive pro-IL-1β mainly detectable only in wild-type mice. CIA, collagen-induced arthritis.