Murine anti-human hepatic and skin monoclonal antibodies will be produced by somatic-cell hybridization in the first year of this contract between SP-2/0 myeloma cells and immunized spleen cells obtained from either BALB/c or KGH rats. The antibodies produced will be tested for Ig class, titer cross-reactivity with other tissues, polymorphism, and relationship to HLA - class I and II specificities (if polymorphic). If monomorphic, these antibodies will be utilized to elute their tissue specific antigens from fresh liver or skin. Mice or rats will be immunized with these solubilizedpartially purified antigens and a second generation of presumably more discriminating polymorphic antibodies produced. In the third year, immunizations with human pancreatic will be performed. When the criteria for polymorphic, non-MHC tissue specificity are satisfied, the MOAb clones will be expanded in tissue culture or ascitic form.