The present disclosure provides methods of treating, preventing, slowing the progression of, or ameliorating the symptoms of T cell mediated immunological diseases, particularly autoimmune diseases (e.g., autoimmune diabetes (i.e. type 1 diabetes or insulin-dependent diabetes mellitus (IDDM)) and multiple sclerosis) through the use of anti-human CD3 antibodies. The antibodies of the disclosure are preferably used in low dose dosing regimens, chronic dosing regimens or regimens that involve redosing after a certain period of time. The methods of the disclosure provide for administration of antibodies that specifically bind the epsilon subunit within the human CD3 complex. Such antibodies modulate the T cell receptor/alloantigen interaction and, thus, regulate the T cell mediated cytotoxicity associated with autoimmune disorders. Additionally, the methods of the disclosure provide for use of anti-human CD3 antibodies modified such that they exhibit reduced or eliminated effector function and T cell activation as compared to non-modified anti-human CD3 antibodies.
