Purification of human interleukin 1 from human monocyte culture supernatants and identity of thymocyte comitogenic factor, fibroblast-proliferation factor, acute-phase protein-inducing factor, and endogenous pyrogen

Abstract

Human interleukin 1 (IL-1) in lipopolysaccharide and silica-stimulated human peripheral blood monocyte culture supernatants was purified to apparent homogeneity by sequential chromatography using DEAE-Sephacel, Sephacryl S-200, CM-high-performance liquid chromatography (HPLC), and hydroxyapatite-HPLC. Analysis by sodium dodecyl sulfate-polyacryl-amide gel electrophoresis (SDS-PAGE) yielded only one band detectable by silver staining with an apparent molecular weight (MW) of 19,000 under nonreducing conditions. IL-1 activity was eluted from a single site from PAGE performed in the absence of SDS. About 4.4 μg of IL-1 was purified from 5.0 liters of culture supernatant of lipopolysaccharide- and silica-stimulated human peripheral blood monocytes, with 46.6% recovery of biological activity. The specific activity of the purified IL-1 was 4.3 × 10 7 U/mg protein. Amino acid composition analysis of the purified human IL-1 was similar to that previously described for murine IL-1. The purified IL-1 exhibited the biological activities previously attributed to IL-1, including thymocyte comitogenic activity, fibroblast proliferation activity, acute-phase protein (haptoglobin)-inducing activity, and endogenous pyrogen activity.