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 epidermal-derived antigen-presenting cell lines (XS series). The purposes of this study were to determine the identity of NS cells and to characterize their functional properties. NS cells were distinguishable from leukocytes by the lack of typical surface markers and by the failure to respond to leukocyte growth factors. Despite their epidermal derivation, NS cells were distinct from keratinocytes by the absence of cytokeratins. On the other hand, NS cells were indistinguishable from lines of dermal fibroblasts by their a) morphology, b) surface phenotype, and c) intracellular deposits of type I collagen. Growth of the XS antigen-presenting lines has been promoted by co-culturing with gamma-irradiated NS cells, and this activity could be replaced with NS cell-conditioned media alone, but not with paraformaldehyde-fixed NS cells. Each clone derived from the NS01 line secreted XS cell-growth-promoting activity, and this activity was blocked by monoclonal antibodies against colony-stimulating factor-1 receptors. Dermal fibroblasts also promoted the growth of XS cells in a colony-stimulating factor-1-dependent manner. By contrast, culture supernatants from other cell lines derived from skin (e.g., Pam 212 keratinocytes, 7-17 dendritic epidermal T cells, or XS lines) failed to promote XS cell growth. These results indicate that NS cells belong to the fibroblast lineage and that they share the intrinsic property to secrete large amounts of colony-stimulating factor-1 with dermal fibroblasts. Dermal cells may support the growth of skin-associated antigen-presenting cells in vivo.

2B4, a new member of the immunoglobulin gene superfamily, is expressed on murine dendritic epidermal T cells and plays a functional role in their killing of skin tumors.

Dendritic epidermal T cells (DETC), which are skin-specific members of the tissue-resident gamma delta T-cell family, are characterized by their potential to kill selected tumor targets by a non-major histocompatibility complex (MHC)-restricted mechanism. We have recently identified a new receptor molecule, 2B4, that appears to be associated with non-MHC-restricted recognition of tumor targets by natural killer cells. The purpose of this study was to determine whether DETC express 2B4 molecules, and, if so, to assess their functional roles in DETC-mediated killing of tumor targets. Short-term DETC lines as well as DETC freshly procured from skin expressed surface 2B4, as detected with a specific monoclonal antibody. Removal of interleukin (IL)-2 from DETC cultures caused substantial reduction in 2B4 expression levels as well as a reduction in cytotoxic capacity against YAC-1 targets in a standard 51Cr-release assay. Conversely, exposure to IL-2, but not to IL-7, elevated both 2B4 expression and cytotoxicity. To assess the functional roles played by surface 2B4, we pretreated DETC lines with anti-2B4 antibody and then tested for their killing potential. Anti-2B4, but not the control antibody, augmented their capacity to lyse YAC-1 targets (51Cr-release assays) and to disrupt the monolayers of Pam-212-transformed keratinocytes (visual assessment). Thus, we conclude that DETC express, in an IL-2-dependent manner, 2B4 molecules, which may play a unique role in the killing of skin-derived tumors.

UVB radiation interrupts cytokine-mediated support of an epidermal-derived dendritic cell line (XS52) by a dual mechanism.

We have established long-term dendritic cell lines from the epidermis of newborn mice. These cell lines (XS series) proliferate maximally in response to granulocyte/macrophage-colony stimulating factor, as well as to CSF-1, which is produced by skin-derived NS fibroblast lines and by keratinocytes (albeit in smaller amounts). The purpose of this study was to examine the impact of UVB radiation on CSF-1-mediated interaction of dendritic cells with fibroblasts and keratinocytes. Exposure of NS cells to UVB radiation (unfiltered FS20 sunlamp) decreased CSF-1 production at mRNA and protein levels. Both changes occurred in a dose-dependent fashion, with 50 J/m2 causing a significant reduction. UVB radiation also downregulated CSF-1 mRNA expression by Pam 212 keratinocytes. UVB exposure of XS cells diminished the surface expression of CSF-1 receptors, with 50 J/m2 causing a significant reduction. Thus, UVB radiation interrupts CSF-1-mediated cell-cell interaction by a dual mechanism: downregulating CSF-1 production and abrogating CSF-1 receptor expression. Importantly, granulocyte/macrophage-colony stimulating factor receptor expression by XS cells was also inhibited by UVB radiation, once again, with 50 J/m2 producing significant inhibition. We propose that the resulting CSF-1 deficiency in epidermal microenvironment and unresponsiveness by dendritic cells to relevant growth factors may contribute to UVB-mediated loss of resident epidermal dendritic cells (i.e., Langerhans cells) in skin.

[Osteoma cutis. Pathogenesis and therapeutic possibilities]. / Osteoma cutis. Pathogenese und therapeutische Möglichkeiten.

No efficacious therapy for the treatment of increasing and spreading cutaneous ossification is yet established. We report a 52 year old white female with multiple miliary osteomas of the skin involving face, chest and back. The patient has a history of acne vulgaris. A therapeutic trial with a diphosphonate (etidronate disodium) was started in order to stop marked progression and appearance of new lesions. In accordance with the two previously described cases of the literature we failed to achieve any improvement. Clinical features, etiology, classification and therapy of osteoma cutis are discussed.

Activation of murine epidermal gamma delta T cells through surface 2B4.

Dendritic epidermal T cells (DETC) are gamma delta T cells that normally reside in murine skin. They express on their surface the 2B4 molecule, a 66-kDa glycoprotein of the immunoglobulin gene superfamily thought to be associated with anti-tumor cytotoxicity by natural killer and lymphokine-activated killer cells. Here, we show that ligation of surface 2B4 transduces cell activation signals in DETC. Treatment with anti-2B4 monoclonal antibodies triggers the secretion of interferon-gamma and interleukin-2 by DETC lines, induces proliferation of resting DETC lines, amplifies anti-CD3-dependent proliferation of DETC freshly isolated from mouse skin; and up-regulates egr-1 and c-fos mRNA expression. These results indicate a unique pathway for DETC activation.