IDENTITY AND FUNCTIONAL-PROPERTIES OF NOVEL SKIN-DERIVED FIBROBLAST LINES (NS SERIES) THAT SUPPORT THE GROWTH OF EPIDERMAL-DERIVED DENDRITIC CELL-LINES

We have established recently a series of unique cell lines (NS series) from dispase-separated mouse epidermis that promote the growth of epi dermal-derived antigen-presenting cell lines (XS series), The purposes of this study were to determine the identity of NS cells and to chara cterize their functional properties, NS cells were distinguishable fro m leukocytes by the lack of typical surface markers and by the failure to respond to leukocyte growth factors, Despite their epidermal deriv ation, NS cells were distinct from keratinocytes by the absence of cyt okeratins. On the other hand, NS cells were indistinguishable from lin es of dermal fibroblasts by their a) morphology, b) surface phenotype, and c) intracellular deposits of type I collagen, Growth of the XS an tigen-presenting lines has been promoted by coculturing with gamma-irr adiated NS cells, and this activity could be replaced with NS cell-con ditioned media alone, but not with paraformaldehyde-fixed NS cells, Ea ch clone derived from the NSO1 line secreted XS cell-growth-promoting activity, and this activity was blocked by monoclonal antibodies again st colony-stimulating factor-1 receptors, Dermal fibroblasts also prom oted the growth of XS cells in a colony-stimulating factor-1-dependent manner, By contrast, culture supernatants from other cell lines deriv ed from skin (e.g,, Pam 212 keratinocytes, 7-17 dendritic epidermal T cells, or XS lines) failed to promote XS cell growth, These results in dicate that NS cells belong to the fibroblast lineage and that they sh are the intrinsic property to secrete large amounts of colony-stimulat ing factor-1 with dermal fibroblasts. Dermal cells may support the gro wth of skin-associated antigen-presenting cells in vivo.