title: Identification of a 24-kDa cytokine that is required for development of cytolytic T lymphocytes.
abstract: It is known that the production of cytolytic T lymphocytes requires growth factors such as interleukins 2 and 4 (IL-2 and IL-4). Elsewhere we have described bioassays that detect a cytokine that operates in concert with growth factor to generate cytolytic T lymphocytes. The factor that is termed cytolytic T-lymphocyte differentiation factor (CDF), together with IL-2 and lectin, mediates the formation of CD8+ killer cells in 2 days from thymocyte or peripheral lymphoid precursors. CDF is not mimicked by natural or recombinant sources of interferons, colony-stimulating factors, and IL-1 to IL-4. Here we use these bioassays to isolate and further characterize a single 24-kDa CDF protein from the conditioned medium of stimulated human blood mononuclear cells. CDF is first enriched by three successive chromatographic procedures that utilize anion exchange, hydroxyapatite, and phenyl-Superose. A single 24-kDa band with CDF activity is then isolated on 12% NaDodSO4/PAGE and clearly distinguished from the 17-kDa band of IL-2. The apparent molecular mass is similar under reducing and nonreducing conditions. After elution from NaDodSO4/PAGE the cytokine is maximally active at 0.25 nM in the CDF assay and has no growth factor activity for T lymphoblasts. To generate cytolytic CD8+, CD4- cells from spleen and lymph node T lymphocytes, IL-2 and small numbers of accessory dendritic cells must be applied together with CDF.
authors.affiliation: Rockefeller University, New York, NY 10021.
authors.forename: C
authors.initials: C
authors.lastname: Cernetti
authors.forename: R M
authors.initials: RM
authors.lastname: Steinman
authors.forename: A
authors.initials: A
authors.lastname: Granelli-Piperno
mesh_terms: D001681:Biological Assay; D001688:Biological Products / Q000032:analysis*; D002454:Cell Differentiation; D002851:Chromatography, High Pressure Liquid; D016207:Cytokines; D003713:Dendritic Cells / Q000502:physiology; D006801:Humans; D066298:In Vitro Techniques; D007376:Interleukin-2 / Q000032:analysis; D013602:T-Lymphocytes, Cytotoxic / Q000502:physiology*
chemical_list: D001688:Biological Products; D016207:Cytokines; D007376:Interleukin-2