Patent ID: 8192739

Claim:
An immunotoxin comprising: (a) a first fusion polypeptide, wherein said fusion polypeptide comprises a non-mammalian ribonuclease fused to a first immunoglobulin variable domain and (b) a second polypeptide comprising a second immunoglobulin variable domain, wherein said first and second immunoglobulin variable domains comprise the CDRs of the immunoglobulin heavy and light chain of an antibody which together form an antigen binding site wherein said non-mammalian ribonuclease is fused to the N-terminus of said first immunoglobulin variable domain, wherein said non-mammalian ribonuclease bears an N-terminal pyroglutamate residue, and wherein the first immunoglobulin variable domain is a light chain variable domain wherein said non-mammalian ribonuclease is ranpirnase or a conservatively modified variant thereof, wherein the antibody is selected from the group consisting of hLL2, hRS7, hLL1 and hMN14, which bind CD22, EGP-1, CD74, and CEA, respectively.