RESTRICTED T-CELL RECEPTOR-V-BETA GENE USAGE BY MYELIN BASIC PROTEIN-SPECIFIC T-CELL CLONES IN MULTIPLE-SCLEROSIS - PREDOMINANT GENES VARY IN INDIVIDUALS

Abstract

Recent studies in experimental autoimmune encephalomyelitis as a model for multiple sclerosis (MS) have demonstrated limited heterogeneity in T-cell antigen receptors (TCR) specific for myelin basic protein (MBP). To investigate restricted beta-chain variable-region (V-beta) gene usage in humans, we analyzed TCR gene rearrangements in two lines and 34 MBP-specific T-cell clones that were isolated from five MS patients and two healthy subjects. The T cells were characterized for their specificity to MBP epitopes and HLA-restricting molecules. We demonstrate here that MBP-specific T-cell clones from these different MS patients and healthy individuals, in contrast to T cells from rodents, display a more diverse V-beta gene usage as evidenced by their TCR V-beta gene rearrangements. However, the different MBP-specific T-cell clones isolated from each individual MS patient showed a common V-beta gene usage, suggesting individual-specific TCR restriction. Out of 16 MBP-specific clones derived from a single MS patient, 12 clones (75%) utilized the V-beta-15 gene for their TCR gene rearrangement. MBP-specific clones isolated from four other MS patients also showed a consistent tendency for a predominant, but different, TCR V-beta gene rearrangement. These results suggest a TCR heterogeneity among MBP-specific T-cell clones from different individuals but a limited TCR V-beta gene usage among MBP-specific T-cell clones of the same individual. The predominant V-beta gene used by the MBP-specific T-cell clones studied here was not found to correlate with the epitope specificity of T cells or with their restricting HLA molecule. These findings may support the possibility of intervention with monoclonal antibodies to specific V-beta gene products as an approach to immune therapy of MS but also imply the necessity for an individual-specific immunotherapeutic approach.