Monoclonal antibodies used in immunotherapy are produced artificially from a cell clone therefore consist of a single type of immunoglobulin. They are targeted towards specific antigens and bind to the antigens to form a complex. The complex can be recognized and destroyed by phagocytes or used for other diagnostic purposes. Anti-CTLA-4 monoclonal antibodies are directed to the inhibitory receptor CD152 (CTLA-4). They may be use to treat certain types of melanoma.