Monoclonal antibody to desmin purified from cow Purkinje fibers reveals a cell-type specific determinant.

We have raised monoclonal antibodies (Mab) to the Mr 55,000 desmin polypeptide, electrophoretically purified from cytoskeletal preparations of isolated bovine heart Purkinje fibers. One of the Mabs, 39AB6, revealed desmin only in cow Purkinje fibers and did not react with desmins from other muscle cells, including ventricular cardiac muscle, striated muscle and smooth muscle, as revealed by both immunoblotting and immunocytochemistry. Desphosphorylation of electrophoretically separated polypeptides on nitrocellulose with alkaline phosphatase did not affect the binding of the Mab. The present results show that there are cell-type specific antigenic determinants in intermediate proteins of the desmin type.