Monoclonal antibody selectively reactive with myelin sheaths of the peripheral nervous system in paraffin-embedded material.

We have produced a monoclonal antibody (PM43) selectively reactive with formalin-fixed paraffin-embedded peripheral nervous system (PNS) myelin. The hybridomas were generated by fusion of mouse myeloma cell line Sp2/0 with spleen cells of BALB/c mice immunized with cultured human melanocytes. Hybridomas were screened by the indirect immunoperoxidase assay. Ouchterlony analysis showed the immunoclass of PM43 to be IgM. By the immunoaffinity chromatography technique, among others a 43-kDa protein was isolated from PNS myelin. The antigenic determinant of PM43 in the mouse is expressed with a similar tissue distribution as observed in man. Expression of the antigenic determinant does not become visible until after birth in mice. PM43 opens further possibilities for the use of anti-myelin antibodies in the study of myelination and demyelination processes in the PNS and remyelination processes in the central nervous system.