INVOLVEMENT OF GP130 INTERLEUKIN-6 RECEPTOR TRANSDUCING COMPONENT IN INTERLEUKIN-11 RECEPTOR/

The recently cloned interleukin (IL)-11 displays many biological prope rties in common with those reported for IL-6. In order to analyze the nature and the functionality of the IL-11 receptor we developed a prol iferative assay using the human multifactor-dependent cell line TF1. W e showed that a blocking monoclonal antibody GPX7 raised against the g p130/IL-6 receptor transducing subunit was also able to inhibit the IL -11-triggered TF1 line proliferation. In addition, involvement of gp13 0 in IL-11 signaling was demonstrated by an induction of the transduci ng protein phosphorylation in response to IL-11, as observed for IL-6. In contrast, the blocking monoclonal antibody B-R6, which recognized the gp80/IL-6 binding subunit, failed to interfere with the IL-11 prol iferative signal in the TF1 cell line. Similarly, we did not observe a ny competition between IL-6 and IL-11 for a putative common binding si te on the cell surface. These results suggest that the IL-11 binding c omponent is different from the gp80/IL-6 receptor. In conclusion, IL-1 1, along with IL-6, leukemia inhibitory factor, oncostatin M and cilia ry neurotrophic factor, belongs to the same family of cytokines, using gp130 as a transducing protein.