US Patent 8697065 Non-natural ribonuclease conjugates as cytotoxic agents

The present invention is directed toward the delivery of a toxic protein to pathogenic cells, particularly cancer cells. In preferred embodiments, the toxic protein is a ribonuclease that has been modified to make it toxic to target cells and that can be conjugated to a target cell-specific delivery vector, such as an antibody, for delivery to pathogenic cells.