Mediator production and gene expression in joints from mice immunized for collagen-induced arthritis. (a) TNF and IL-1β levels in joint washouts following collagen-induced arthritis (CIA). TNF and IL-1β were measured by ELISA at sacrifice in washouts from ankle joints of C57 → C57 (n = 12), C57 → u-PA-/- (n = 16), u-PA-/- → C57 (n = 11) and u-PA-/- → u-PA-/- (n = 9) mice. *P < 0.05, **P < 0.01, C57 → u-PA-/- vs. u-PA-/- → u-PA-/- mice; ***P < 0.05, ****P < 0.01, u-PA-/- → C57 vs. C57 → C57 mice. (b) TNF, IL-1β, IL-6 and MCP-1 gene expression levels in joints following CIA (n = 6 for each group). C57 or C57 → u-PA-/- vs. u-PA-/- mice, P < 0.05 for each cytokine. (c) Tissue-type plasminogen activator (t-PA), urokinase-type plasminogen activator (u-PA) and urokinase-type plasminogen activator receptor (u-PAR) gene expression levels in joints following CIA (n = 6 for each group). C57 vs. u-PA-/- mice, P < 0.05, t-PA and P < 0.01, u-PAR; C57 → u-PA-/- vs. u-PA-/- mice, P < 0.05, u-PAR. For (b) and (c), expression levels were normalized to an endogenous control (TATA-binding protein (TBP)) and calibrated relative to expression in C57BL/6 mice. For all, values expressed as mean level ± standard error of the mean.