The proposed studies will utilize direct and indirect immunofluorescence techniques and histochemical staining procedures for the identification of cells in tissue sections and in suspensions following extraction from skin lesions. The response of cells extracted from LE skin lesions to mitogens, common antigens and putative "autoantigens" will be examined using standard blastogenic responses and assays for lymphokine activity. Immunoglobulin secreting cells from LE skin lesions will be quantitated by a reverse hemolytic plaque assay before and after stimulation with pokeweed mitogen. Both the direct immunofluorescence (Crithidia luciliae anti-DNA test) and a solid phase radioimmunoassay will be used to identify DNA antibody in serum samples, tissue eluates and cell culture supernates. Fluorescein conjugated anti-DNA antibody will be used to identify DNA at the dermal-epidermal junction in LE skin lesions an in uninvolved LE skin. Ethidium bromide, a fluorescent dye that binds to DNA will also be used to identify subepidermal DNA. Autoradiographic and electron microscopic techniques will be used to trace epidermal DNA in NZB/W mice and to assess the relationship between variation in rates of epidermal cell division and accumulation of subepidermal immunoglobulin deposits. The role of DNA binding to collagen in the subepidermal region as a localizing factor for DNA anti-DNA complexes will be further explored. The primary objectives of this research are to define in modern terms the immunopathologic mechanisms of cutaneous LE and to examine the relationship between the cutaneous and systemic aspects of lupus erythematosus. These studies will provide insight into the relative roles of cellular versus humoral mechanisms in the pathogenesis of LE skin disease amd many lead to a more rational approach to treatment.