My research investigates the specificity of IgG in patients with multiple sclerosis (MS) using phage-displayed peptide libraries approach. A hallmark of MS is the persistence of oligoclonal IgG and elevated numbers of B cells in the CNS. Our published studies have demonstrated the antigen-driven response of clonally expanded B cells in MS. We are using recombinant antibodies generated from these B cells to identify peptide epitopes/mimotopes by panning phage-displayed random peptide libraries. The specificity of the peptides is confirmed by ELISA, immunoblots and competitive inhibition assays. By applying a highly sensitive phage mediated immuno-PCR technique, these peptides are screened for bindings to IgG in multiple MS patients. MS peptides can then be used to determine the corresponding protein antigens using bioinformatics approach. Identification of MS antigens has the potential to determine the cause of disease, and to develop strategies for diagnostic and therapeutic intervention.