Fig. 4.

s-JIA sera interfere with the binding of the IL-6/sIL-6R complex to gp130. (a) Amount of IL-6/gp130 binding activity generated in controls and s-JIA sera following exogenous addition of IL-6. Sera were preincubated with 4 ng/ml of recombinant human IL-6 and then tested in the IL-6/gp130 binding activity assay. Results are shown as means + SE, represented by the vertical bars, of triplicate determinations. The horizontal dotted line indicates the 4 ng/ml amount of IL-6 that was exogenously added. (b) Dose dependent inhibition of the IL-6/gp130 binding activity obtained adding increasing percentages of sera of patients with active s-JIA (s-JIA Pool) to a normal control serum incubated with 1 ng/ml of rhIL-6.