The major objective of this proposal will be the isolation, purification and characterization of the epidermal antigens reactive with pemphigus and bullous pemphigoid antibodies. Methods to be utilized for these studies will include direct tissue and preparative tissue isoelectric focusing, and standard two dimensional gel electrophoresis. Whole skin, various populations of epidermal cells grown in culture and monkey esophagus will be the major tissue sources. Purified antigens will be compared to antigens isolated by other methods and to produce and characterize monomclonal antibodies. Such antibodies will be utilized to harvest larger quantities of antigens and in studies of differentiation of epidermal cells in culture. Purified antigens will also be utilized in studies of lymphocytes and lymphocyte function of patients with pemphigus and bullous pemphigoid and hopefully in the development of animal models. The above methodology will also allow us to study the heterogeneity of both pemphigus and bullous pemphigoid antibodies and antigens. Using epidermal cells grown in culture we hope to learn something about the expression and fate of these antigens during differentiation, particularly at the level of the electron microscope. Finally, using both short term organ culture and epidermal cell cultures, we hope to determine whether pemphigus antibodies will fix complement, and if so, what role complement plays in acantholysis. Perturbations in various lymphocyte subpopulations should provide information concerning immunoregulatory abnormalities in these patients. We hope that our studies will shed new light upon several major controversies and provide new information and direction for immunopathologic investigations in these two bullous diseases.