Disclosed are compositions and methods for the prevention and treatment of autoimmune conditions by selectively reducing or expanding T cells according to the antigenic specificity of the T cells. Therefore, the present invention can be used to reduce or eliminate pathogenic T cells that recognize autoantigens, such as beta cell specific T cells. As such, the present invention can be used to prevent, treat or ameliorate autoimmune diseases such as IDDM. Furthermore, the present invention can be used to expand desirable T cells, such as anti-pathogenic T cells to prevent, treat and/or ameliorate autoimmune diseases.