A Comparative Study of the Immunologic Properties of Hoof and Nail Fibrous Proteins

We have studied the localization of epidermal (soft) and nail and hoof (hard) fibrous keratins in the various anatomic regions of bovine hoof and human nail. Indirect immunofluorescence was performed on frozen sections of various parts of hoof and nail with antibodies demonstrated to be specific for hard and soft fibrous keratins by the Ouchterlony technique. The antibody to hard fibrous keratin reacted with the upper region of hoof bed and matrix tissue but not perihoof epidermis. The antibody to soft fibrous keratin reacted with hoof bed, matrix tissue, and perihoof epidermis. Electrophoretic analysis of the fibrous proteins of hoof bed indicated they contained both soft and hard fibrous keratins while matrix tissue contained only hard keratins. Immunoblot analysis of matrix fibrous proteins indicated that most of the polypeptides reacted with both antibodies. These results indicate that the antibody to soft fibrous keratin cross-reacts with hard fibrous keratin but the antibody to hard fibrous keratin appears to be specific. Immunologic studies, therefore, must be correlated with electrophoretic studies in order to define the localization of the various types of fibrous keratins. Similar results were obtained with human nail