ABSTRACT
T lymphocytes are widely accepted as playing a major role in the pathogenesis of autoimmune diseases. T cells are activated via specific receptors, termed T cell antigen receptors or T cell receptors (TCRs), which tum on a cascade of intracellular events culminating in cell activation and cytokine release that drives the inflammatory response. This chapter discusses the molecular structure of TCRs, their interaction with major histocompatibility antigens, and the focus of this complex as a target to developing new treatment modalities. Mature T cells that bear α and β TCRs generally fall into two categories: CD4+ and CD8+. The collagen-induced arthritis system is characterized by oligoclonal expansion of type II collagen-specific T cells. The Ag-major histocompatibility complex specificity of the multiple sclerosis plaque-infiltrating T cells has been the subject of intensive investigation. Myasthenia gravis is a neuromuscular disease caused by autoimmune destruction of acetylcholine receptors at the neuromuscular junction.
