Myelin is a membrane characteristic of the nervous tissue and functions as an insulator to increase the velocity of the stimuli being transmitted between a nerve cell body and its target. Myelin isolated from human and bovine nervous tissue is composed of ~80% lipid and 20% protein, and 30% of the protein fraction constitutes myelin basic protein (MBP). MBP is an 'intrinsically unstructured' protein with a high proportion (~75%) of random coil, but postulated to have core elements of beta-sheet and alpha-helix. MBP is a major protein in CNS myelin and is expressed specifically in the nervous system. A detailed immunochemical examination of monoclonal and polyclonal antibody responses to MBP and its peptides has revealed the existence of as many as 27 antigenic determinants, many of them conformational. Topological mapping of the potential antigenic determinants onto a model of MBP secondary structure places these determinants within 11 separate regions of the molecule, including those portions that have been found to be encephalitogenic. The message for myelin basic protein is selectively translocated to the ends of the cell processes. Immunization with myelin-associated antigens including MBP significantly promotes recovery after spinal cord contusion injury in the rat model.