title: Thy-1+ dendritic epidermal cells in mice: precursor frequency analysis and cloning of concanavalin A-reactive cells.
abstract: Bulk cultures of mouse Thy-1+ dendritic epidermal cells (Thy-1+ DEC) have been shown to proliferate in response to concanavalin A (Con A) and IL-2, to secrete IL-2-like growth factors, and to lyse target cells such as YAC-1. Limiting dilution microculture was utilized in order to determine the precursor frequency of Con A-responsive Thy-1+ DEC in suspensions of AKR/J epidermal cells as well as whether these several functional activities all reside within a single Thy-1+ DEC precursor. Precursor frequency analysis of cultures established with limiting numbers of FACS-purified Thy-1+ DEC, irradiated syngeneic splenic filler cells and exogenous IL-2 indicated that approximately 20% of Thy-1+ DEC proliferated in response to Con A. Parallel microcultures in which purified Thy-1+ DEC were plated at a density of 0.5 cells/well were used to establish clones. Twenty clones were characterized phenotypically, and ten of these were also tested for their capacities to proliferate in response to Con A or IL-2, to secrete IL-2-like growth factors, and to exhibit cytotoxicity. All clones were Thy-1+ and L3T4-, but while most were also Lyt-2-, several contained 3%-18% dull Lyt-2+ cells. Functional studies revealed that each clone displayed all of the above functional activities, albeit with substantial quantitative variation. Clones with the highest cytotoxic activity had relatively low responsiveness to Con A or IL-2 and included all clones containing dull Lyt-2+ cells; conversely, clones with the highest proliferative responses had relatively low cytotoxic activity and were all Lyt-2-. This degree of functional and phenotypic heterogeneity among cloned Thy-1+ DEC may reflect their particular states of activation or differentiation; whether it reflects the biologically relevant in vivo activities of these cells must still be determined.
mesh_terms: D000818:Animals; D000954:Antigens, Surface / Q000032:analysis*; D002455:Cell Division / Q000187:drug effects; D002999:Clone Cells; D003208:Concanavalin A / Q000494:pharmacology*; D003584:Cytological Techniques; D003602:Cytotoxicity, Immunologic; D003713:Dendritic Cells / Q000166:cytology / Q000276:immunology* / Q000378:metabolism / Q000502:physiology; D000078404:Epidermal Cells; D004817:Epidermis / Q000276:immunology* / Q000378:metabolism / Q000502:physiology; D007376:Interleukin-2 / Q000378:metabolism / Q000494:pharmacology / Q000502:physiology; D051379:Mice; D008815:Mice, Inbred Strains; D010641:Phenotype; D018800:Thy-1 Antigens
chemical_list: D000954:Antigens, Surface; D007376:Interleukin-2; D018800:Thy-1 Antigens; D003208:Concanavalin A