Definition

Purified gamma globulin, with immunosuppressive activity. Obtained from animals that have been immunized with human thymocytes, antithymocyte globulin (ATG) specifically recognizes and destroys T lymphocytes. Although not completely understood, the mechanism of action appears to involve T lymphocyte clearance from the circulation and modulation of T lymphocyte activity. Administering ATG with chemotherapy prior to stem cell transplantation may reduce the risk of graft-versus-host (GVH) disease.