Figure 3.

TLR4-mediated IL-12 production enhances joint IFN-γ and IL-1β production in antibody-induced arthritis. (A and C) Spleen cells from WT or interleukin(IL)-12Rβ₂^-/- mice were stimulated with LPS and/or recombinant IL-12, and amounts of IFN-γ and IL-1β were measured in the culture fraction by ELISA. (B) Intracellular T-bet expression was measured in joint cells from WT mice, some of which had been stimulated with LPS and/or recombinant IL-12, by flow cytometry. In addition, spleen cells from TLR4^-/- mice were stimulated with LPS and/or recombinant IL-12. (D) Joint cells from WT mice with antibody-induced arthritis were stimulated with LPS and/or recombinant IL-12. Western blotting was performed to measure amounts of pro-IL-1β in these joint cells as compared with β-actin levels. The results shown are representative of three repeated independent experiments. n.s. not significant; * P < 0.05, ** P < 0.01, *** P < 0.001.