Improved methods for the application of random peptide phage libraries to the study of the oligoclonal bands in cerebrospinal fluid of patients with multiple sclerosis

The target antigens of the oligoclonal bands in the cerebrospinal fluid (CSF) of patients with multiple sclerosis (MS) are unknown but may reflect important autoantigens in MS. One approach to identify candidate antigens is to allow CSF to select peptide motifs from a random phage library. To determine whether selected peptide motifs are related to the pathogenesis of MS, it is important to know if other MS patients and appropriate control patients have antibodies reactive with these sequences either in CSF or sera. Unfortunately, serologic screening of such sequences directly in phage clones gave non-specific reactions. Western blotting was found to obviate the non-specificity problem and together with isoelectric focusing, could also be used to demonstrate the co-migration of antigen specific oligoclonal bands with individual total IgG bands. Using 2D gel electrophoresis, absorption of CSF antibodies by specific peptide sequences selected from the phage library could be demonstrated. These techniques should facilitate the systematic study of the targets of the oligoclonal bands in CSF of patients with MS.