Recombinant Immunotoxins in the Treatment of Cancer

Recombinant immunotoxins are chimeric proteins composed of the Fv portion of a monoclonal antibody (MAb) fused to a portion of a toxin. The Fv replaces the cell-binding domain of the toxin and directs the toxin to cancer cells that express a target antigen. There are several features that make toxins attractive agents designed to kill cancer cells. They are very potent, and they are able to kill cells that are resistant to standard chemotherapy. Recombinant immunotoxins (RITs) have been produced that kill different types of cancer cells, as well as human immunodeficiency virus (HIV)-infected cells, taking advantage of gp120 on the surface of HIV-infected cells.