Establishment of the ELISA for murine soluble gp130, a signal transducer for the IL-6 family cytokine, and its detection in the ascitic fluids of tumor-bearing mice.

Interleukin-6 (IL-6) signal is transduced through a membrane glycoprotein gp130, which associates with the IL-6 receptor alpha chain (IL-6R alpha) in the presence of IL-6. We prepared monoclonal antibodies (mAbs) specific to murine gp130 by immunizing rats and hamsters with a chimeric molecule consisting of the extracellular domain of murine gp130 and human immunoglobulin (Ig) G1 Fc (m130Ig). Furthermore, we developed a sandwich ELISA for detection of murine soluble gp130 (sgp130) and showed that sgp130 was present in the ascitic fluids of tumor-bearing mice. Because sgp130 can inhibit the biological activities of the IL-6-related cytokine subfamily that can enhance anti-tumor immune response and also has both growth inducing and growth inhibitory activities on various tumors, the results suggest that sgp130 in tumor-bearing host modulates tumor progression.