Partial purification and characterization of the active entity responsiblefor inducing interleukin-6 production by human gingival fibroblasts from Mycoplasma salivarium cells

The active entity responsible for inducing interleukin-6 production by huma n gingival fibroblasts was partially purified by ion-exchange chromatograph y from the water-soluble fraction of Mycoplasma salivariurn cells, Sodium d odecyl sulfate-polyacrylamide gel electrophoresis of the final preparation revealed one densely stained band with a molecular weight of 20.6 kilodalto ns and two faint bands with molecular weights of 40.5 and 82.5 kilodaltons, The specific activity of the final preparation was 34-fold higher than tha t of the starting water-soluble fraction. The interleukin-6-inducing activi ty was destroyed by proteinase K and reduced 70% by lipoprotein lipase and heat treatment, but was not affected by deoxyribonuclease I or endoglucosid ase D. The final preparation induced small amounts of tumor necrosis factor -alpha and interleukin-lp in a myelomonocytic cell line, THP-1 cells, but d id not induce interleukin-6. The ability of Escherichia coli lipopolysaccha ride to stimulate human gingival fibroblasts to release interleukin-6 was d ependent upon the presence of serum in the assay medium, but that of the fi nal preparation from M. salivarium was not, Thus, we partially purified the protein(s) from M, salivarium which were capable of stimulating human ging ival fibroblasts to release interleukin-6 by a mechanism different from tha t of E. coli lipopolysaccharide.