Abstract: Various aspects of the invention relate to compositions comprising polycytotoxic T cells. Some aspects relate to methods for obtaining a composition comprising polycytotoxic T cells. Some aspects relate to methods of administering a composition comprising polycytotoxic T cells to a subject. Some aspects relate to methods for monitoring an immune response in a subject, comprising determining the concentration of polycytotoxic T cells in the blood of the subject. Some aspects relate to methods for treating a condition or disease in a subject, comprising administering to the subject a composition comprising an antibody, or an antigen-binding portion thereof, that specifically binds to a protein expressed by a polycytotoxic T cell.