A monoclonal antibody being studied in the treatment of melanoma and some other types of cancer. Ticilimumab is made in the laboratory and binds to a protein called CTLA-4 on T cells (a type of white blood cell). CTLA-4 is involved in preventing the activation of T-cells. Ticilimumab may block CTLA-4 and help the immune system kill cancer cells. It is a type of immunomodulatory agent.