Immunization with a complementary peptide (RhCA 611-001), encoded by mRNA complementary to that of the TCR epitope, residues 100-116 of Torpedo AChR α-subunit, was previously shown to induce the production of anti-TCR Ab which blocked TCR recognition specific to AChR 100-116 and prevented the development of EAMG. In the present report, we show that a mAb to RhCA 611-001 (CTCR8, IgG2 κ) recognised Vβ of TCR specific to AChR 100-116 and blocked the proliferation of AChR 100-116 specific T-cell lines. The analysis of the nucleotide sequences of T-cell lines showed limited heterogeneity (only four patterns) two of which were completely recognized by CTCR8. Our results demonstrated a new immunotherapy for myasthenia gravis and other autoimmune disease through the induction of anti-TCR Abs by peptide immunogens. Supported in part by the NDRC and MDSC (Japan).