Binding of hIL-6 and vIL-6 to sIL-6R chains as detected by ELISA.

Purified sIL-6R (5 μg/mL) or sgp130 (5 μg/mL) or both were immobilized on an ELISA plate and incubated with hIL-6 (50 ng/mL) or MBPvIL-6 (50 ng/mL). Bound protein was detected with a rabbit polyclonal anti–hIL-6 antibody that recognizes hIL-6 but not vIL-6 (A) or anti–MBPvIL-6 antibody that recognizes vIL-6 but not hIL-6 (B), followed by HRP-conjugated antirabbit IgG antibodies. The results represent the means of triplicate assays; error bars represent SD. Representative data from 3 independent experiments are shown.