title: A recombinant single-chain immunotoxin composed of anti-Tac variable regions and a truncated diphtheria toxin.
abstract: To kill human or primate cells expressing the p55 subunit of the interleukin 2 receptor, we have constructed a single-chain immunotoxin. DNA sequences encoding the first 388 amino acids of diphtheria toxin (DT) were fused to DNA elements encoding the antigen-binding portion (variable region or Fv) of the anti-Tac monoclonal antibody. The antigen-binding portion consists of 116 amino acids of the heavy-chain variable region connected by a 15-amino acid linker to 106 amino acids of the variable region of the light chain. The single-chain immunotoxin DT388-anti-Tac(Fv) was expressed in Escherichia coli and found in inclusion bodies. The monomeric form was then purified to near homogeneity with a high yield (3-5 mg/liter). Monomeric DT388-anti-Tac(Fv) was highly cytotoxic to cell lines bearing the p55 subunit of the human interleukin 2 receptor but not to cells without this subunit. DT388-anti-Tac(Fv) was also very effective in killing proliferating human T cells produced in a mixed leukocyte reaction.
authors: Division of Cancer Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892.
authors: V K
authors: VK
authors: Chaudhary
authors: M G
authors: MG
authors: Gallo
authors: D J
authors: DJ
authors: FitzGerald
authors: I
authors: I
authors: Pastan
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D001483:Base Sequence; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D003001:Cloning, Molecular; D004167:Diphtheria Toxin / Q000235:genetics / Q000494:pharmacology*; D004926:Escherichia coli / Q000235:genetics; D006801:Humans; D000922:Immunotoxins / Q000494:pharmacology*; D007930:Leucine / Q000378:metabolism; D008969:Molecular Sequence Data; D010957:Plasmids; D015375:Receptors, Interleukin-2 / Q000276:immunology*; D011994:Recombinant Proteins / Q000494:pharmacology; D015183:Restriction Mapping
chemical_list: D000911:Antibodies, Monoclonal; D004167:Diphtheria Toxin; D000922:Immunotoxins; D015375:Receptors, Interleukin-2; D011994:Recombinant Proteins; D007930:Leucine