Differentiation-inducing cytokine P48 exists in a membrane-associated form.

摘要: P48 is a recently described 48-kDa differentiation-inducing cytokine isolated from the culture medium of human leukemia line Reh. induces differentiation and cytolytic activity in promyelocytic cell HL-60, stimulates release TNF-alpha IL-1 peripheral blood monocytes. In further studies designed to examine biosynthesis function P48, surface immunofluorescence flow cytometry analysis as well 125I labeling immunoprecipitation, revealed presence on Reh cells. Triton X-114-treated cells were partitioned into detergent aqueous phases separated by SDS-PAGE. Western blot that exclusively phase, suggesting an integral membrane association. fixed with paraformaldehyde, but not K562 or P815, able stimulate monocytes manner similar secreted P48. Isolated plasma membranes could also release. This TNF-alpha-releasing be removed solubilized immunoaffinity chromatography anti-P48 column. study suggests that, addition being medium, expressed biologically active form. The form may 1) final maturation step before secretion 2) membrane-associated analogous forms IL-1.