Identification of autoimmune encephalomyelitis-associated common CDR3 sequences by CDR3 spectratyping and subsequent DNA hybridization.

In previous studies, we demonstrated that T cell receptor (TCR) Vbeta8.2 and Vbeta10, both of which are frequently used by encephalitogenic T cells, spectratypes expand oligoclonally in spinal cord lesions of Lewis rats with experimental autoimmune encephalomyelitis (EAE) and that the DSSYEQYF and WDGSGNVLYF sequences are predominantly found in the complementarity-determining region 3 (CDR3) of spectratype-derived TCR clones. However, it is unknown whether these CDR3 sequences are used only by Vbeta8.2- and Vbeta10-positive T cells or by encephalitogenic T cells bearing Vbetas other than these Vbetas. The present study was undertaken to address this issue using a new approach, i.e. CDR3 spectratyping and subsequent DNA hybridization with several probes corresponding to various parts of the CDR3 region. Consequently, we found that probes specific for the Vbeta8.2 spectratype-derived Dbeta and Jbeta2.7 hybridized only with the Vbeta8.2 spectratype in acute EAE and with the Vbeta8.2 and Vbeta12 spectratypes in chronic relapsing EAE. Similarly, a probe specific for the Vbeta10 spectratype-derived Dbeta hybridized only with the Vbeta10 spectratype in both acute and chronic relapsing EAE. In contrast, a probe specific for Jbeta1.3 hybridized with several Vbeta spectratypes including Vbeta8.2 and Vbeta10 only during the early stage of the disease. These findings suggest that T cells bearing a few Vbetas with a limited number of the CDR3 sequences are activated in acute and chronic relapsing EAE induced in Lewis rats. Characterization of the CDR3 region of pathogenic TCR by this approach may be of value for the screening of autoimmune disease-associated TCR and for the development of TCR-based specific immunotherapy.