ABSTRACT
Interleukin-6 (IL-6) is synthesized and secreted by many different cells after appropriate Stimulation. IL-6 confers its signal to target cells by binding to IL-6-specific cell-surface receptors. Recombinant human IL-6 (rhIL-6) was iodinated according to the procedure of Markwell, with modifications as previously described. IL-6 is synthesized as a precursor with an extra-amino-terminal extension of 28 amino acids. The reason for the construction of chimeras of mouse and human IL-6 was based on the observation that human IL-6 is recognized by the human as well as by the mouse IL-6 receptor, whereas murine IL-6 exerts its action only on the mouse IL-6 receptor. The cDNA cloning of the IL-6 receptor from human and rat liver revealed that liver cells and leukocytes express the same type of IL-6 receptor, indicating that different biological responses are obtained via an identical receptor.
