[Anti-receptor antibody and autoimmune disease]

Many receptors are located on the cell surface, and accessible by anti-receptor autoantibodies. After binding to the receptor, anti-receptor autoantibodies may activate the receptor, mimicking the effect of its genuine ligand, or inhibiting activation by ligands. Therefore, anti-receptor autoantibodies have pathogenic importance in several autoimmune diseases, such as Graves' disease, myasthenia gravis, Type B insulin resistance syndrome, and so on. The measurement of anti-receptor autoantibodies is often essential in the diagnosis of these diseases. There are two kinds of measurement procedures. One measures only binding or inhibition of ligand binding to the receptors. That test is simple and available in many laboratories, but cannot distinguish the function--stimulation or inhibition--of autoantibodies. However, procedures that can measure function are rather complicated and may not be available in some laboratories. Not only important for diagnosis, anti-receptor autoantibodies can also be utilized to study receptor-ligand interactions and receptor activation. Recently, there are many studies wherein genetically modified receptors are used for analysis. Here, we will present some our results, as examples.