title: Colony promoting activity (CPA) is a novel factor distinct from IL-6.
abstract: The supernatant (CM) of long-term bone marrow culture (LTBMC) contains colony promoting activity (CPA) which does not have granulocyte-macrophage (GM) colony-stimulating activity but which enhances GM-colony formation in the presence of CSF. CPA is different from IL-1, IL-3 and GM, G-, and M-CSF. Since CPA-containing LTBMC-CM always contains a substantial level of IL-6, CPA was thought to be similar to IL-6. In the present study, we found that LTBMC with a particular batch of horse serum produced IL-6 without a corresponding production of CPA. Addition of IL-6 to GM-colony assay system in the presence of GM-CSF did not enhance the colony formation. LTBMC-CM did not stimulate proliferation nor differentiation of mast cell progenitors. Anti-IL-6 antibodies suppressed IL-6 activity, but not CPA. These results indicate that CPA is a novel factor distinct from IL-1, IL-3, G-, M-, GM-CSF, IL-6 and SCF (c-kit ligand).
authors.affiliation: Department of Biology, Faculty of Science, Niigata University, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Sugimoto
authors.forename: S
authors.initials: S
authors.lastname: Taniguchi
authors.forename: T
authors.initials: T
authors.lastname: Yanai
authors.forename: K J
authors.initials: KJ
authors.lastname: Mori
mesh_terms: D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D001854:Bone Marrow Cells; D002417:Cattle; D002478:Cells, Cultured; D003115:Colony-Stimulating Factors / Q000187:drug effects / Q000302:isolation & purification* / Q000494:pharmacology; D015850:Interleukin-6 / Q000276:immunology / Q000378:metabolism / Q000494:pharmacology; D051379:Mice; D013234:Stem Cells / Q000187:drug effects
chemical_list: D000906:Antibodies; D003115:Colony-Stimulating Factors; D015850:Interleukin-6