CYTOKINE-DEPENDENT REGULATION OF GROWTH AND MATURATION IN MURINE EPIDERMAL DENDRITIC CELL-LINES

We have recently established dendritic cell (DC) lines (XS series) fro m the epidermis of newborn mice by repeated feeding with granulocyte/m acrophage-colony-stimulating factor (GM-CSF) and culture supernatants from skin-derived stromal cell lines (NS series). XS lines resemble re sident Langerhans cell (LC), which are immature DC that reside in epid ermis, by their surface phenotype and antigen-presenting profile. XS l ines further resemble resident LC in that they express mRNA for interl eukin-1 beta and macrophage inflammatory protein (MIP)-1 alpha, and by the absence of mRNA for IL-6. Their growth is promoted by GM-CSF, col ony-stimulating factor-1 (CSF-1), or NS culture supernatant, and inhib ited by interferon-gamma or tumor necrosis factor-alpha. The expressio n by the XS lines of Ia molecules is up-regulated by GM-CSF and down-r egulated by NS supernatant. These results suggest the existence of neg ative regulatory mechanisms in which the growth and/or maturation of D C is suppressed by selected cytokines.