ATGAM Sterile Solution contains lymphocyte immune globulin, anti-thymocyte globulin [equine]. It is the purified, concentrated, and sterile gamma globulin, primarily monomeric IgG, from hyperimmune serum of horses immunized with human thymus lymphocytes. ATGAM is a transparent to slightly opalescent aqueous protein solution. It may appear colorless to faintly pink or brown and is nearly odorless. It may develop a slight granular or flaky deposit during storage [see Dosage and Administration (2.2)].
Precise methods of determining the potency of ATGAM have not been established, thus activity may potentially vary from lot to lot. Before release for clinical use, each lot of ATGAM is tested to assure its ability to inhibit rosette formation between human peripheral lymphocytes and sheep red blood cells in vitro. In each lot, antibody activity against human red blood cells and platelets is also measured and determined to be within acceptable limits. Only lots that meet the acceptance criteria for pyrogens and test negative for antihuman serum protein antibody and antiglomerular basement membrane antibody are released.
Each milliliter of ATGAM contains 50 mg of horse gamma globulin stabilized in 0.3 molar glycine to a pH of approximately 6.8.