Immunotoxins comprising ribosome-inactivating proteins

A method for elimination of a particular cell in a patient in need of the same, wherein said method comprises:

• (A) administering, to said patient, a fusion protein comprising
• (i) a gelonin sequence that is a non-naturally occurring analog of gelonin SEQ ID No. 2 or SEQ ID No. 101, wherein a cysteine is substituted for another amino acid at an amino acid position not naturally available for intermolecular disulfide bonding in said gelonin SEQ ID No. 2 or SEQ ID No. 101, said cysteine being available for intermolecular disulfide bonding, said cysteine being substituted at an amino acid position in said gelonin from position 239 to the carboxy terminus of SEQ ID No. 2 or SEQ ID No. 101, and wherein said analog retains the ability to inactivate ribosomes;
• and
• (ii) a targeting sequence that allows the internalization of said fusion protein, wherein said targeting sequence is an antibody, an antigen-binding portion of an antibody, a hormone, a lymphokine or a growth factor,
• (B) internalizing said fusion protein in said cell, and
• (C) eliminating said cell as a result of said internalization.