DESCRIPTION (provided by applicant): EAE has served as a useful model for MS, yet many therapies which succeed in preventing or reversing paralysis in the animal model, do not succeed when applied to MS. However, approved drugs for MS like beta interferon and Copaxone have been successful in both EAE and MS. There are several convenient models of EAE in rodents with both acute and relapsing features along with demyelination. We shall examine transcription profiles in MS lesions using gene microarray technologies, comparing the transcriptional profiles of these lesions from six MS brains. Genes of interest found in microarray analysis will be corroborated with real time PCR RNAse protection, and Western blotting in selective cases. Lesions, where mRNA was isolated, will also be characterized histopathologically and immunohistochemically. We shall continue comparison of active and chronic lesions, where we have already identified key differences in transcription of immunoglobulin genes p38kinase and alpha-1-antichymotrypsin. Profiles from MS brain will be compared to those obtained from the CNS of rodents with relapse, remission, or acute attacks of EAE. We shall also study transcriptional profiles of pathogenic T cell clones that cause EAE, either stimulated with native myelin peptide or altered peptide ligands. APL's have been successful in treating EAE, and have now been taken into phase II trials in MS. Finally we will study the role of osteopontin a gene identified in large scale transcriptional profiling of EAE and MS. We demonstrate that osteopontin is expressed in MS and EAE lesions, and that in animals with the osteopontin gene deleted there is a profound change in the regulation of disease relapses. The discovery of the role of osteopontin, first identified in large scale profiles, exemplifies how this approach may help us to understand MS and to develop new therapies.