Immunochemical Characterization of Peripheral Nervous System Myelin 170,000‐Mr Glycoprotein

Abstract

A recently described 170,000-Mr glycoprotein, specific to peripheral nervous system (PNS) myelin, was purified from rat PNS myelin by preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis and used to immunize guinea-pigs and rabbits. The resultant antisera proved specific for 170,000-Mr glycoprotein by enzyme-linked immunosorbent assay, by immunoprecipitation of the appropriate peptide from solubilized PNS myelin, and by immunoblot analysis of rat PNS myelin. The anti-rat 170,000-Mr glycoprotein antisera cross-reacted with proteins of similar molecular weight in human and bovine PNS myelin, but such proteins were not detected in human or rat CNS myelin or other rat tissues. The 170,00-Mr glycoprotein was also detected by this immunoblot procedure in recently isolated rat Schwann cells but not in those kept in culture for .gtoreq. 3 days. By indirect immunofluorescent microscopy, anti-rat 170,000-M4 glycoprotein antibody bound to rat PNS myelin sheaths but not to other rat tissues. Together, these studies indicate the 170,000-Mr glycoprotein is specific to PNS meylin of several species and that a neuronal influence may be required for its expression by Schwann cells.