The invention relates to an isolated immunoglobulin heavy chain polypeptide and an isolated immunoglobulin light chain polypeptide that bind to a protein encoded by the T Cell Immunoglobulin and Mucin Protein 3 ( 3). The invention provides a TIM 3 binding agent that comprises the aforementioned immunoglobulin heavy chain polypeptide and immunoglobulin light chain polypeptide. The invention also provides related vectors compositions and methods of using the TIM 3 binding agent to treat a disorder or disease that is responsive to TIM 3 inhibition such as cancer an infectious disease or an autoimmune disease.