An anti-CD30 single-chain Fv selected by phage display and fused to Pseudomonas exotoxin A (Ki-4(scFv)-ETA') is a potent immunotoxin against a Hodgkin-derived cell line.
The human CD30 receptor is highly overexpressed on the surface of Hodgkin Reed-Sternberg cells and has been shown to be an excellent target for selective immunotherapy using monoclonal antibody-based agents such as immunotoxins. To construct a new recombinant immunotoxin for possible clinical use in patients with Hodgkin's lymphoma, we have chosen the murine anti-CD30 hybridoma Ki-4 to generate a high-affinity Ki-4 single-chain variable fragment (scFv). Hybridoma V-genes were polymerase chain reaction-amplified, assembled, cloned and expressed as a mini-library for display on filamentous phage. Functional Ki-4 scFv were obtained by selection of binding phage on the Hodgkin lymphoma-derived, CD30-expressing cell line L540Cy. The selected recombinant Ki-4 scFv was shown to specifically bind to an overlapping epitope on the CD30 antigen with binding kinetics similar to those of the original antibody. The Ki-4 scFv was subsequently fused to a deletion mutant of Pseudomonas exotoxin A (ETA'). The resulting immunotoxin Ki-4(scFv)-ETA' specifically binds to CD30+ L540Cy cells and inhibits the protein synthesis by 50% at a concentration (IC50) of 43 pM. This recombinant immunotoxin is a promising candidate for further clinical evaluation in patients with Hodgkin's lymphoma or other CD30+ malignancies.
Klimka
A
A
Department of Internal Medicine I, University Hospital Cologne, Germany.
Barth
S
S
Matthey
B
B
Roovers
R C
RC
Lemke
H
H
Hansen
H
H
Arends
J W
JW
Diehl
V
V
Hoogenboom
H R
HR
Engert
A
A
D001427:Bacterial Toxins / Q000494:pharmacology*; D005098:Exotoxins / Q000235:genetics / Q000494:pharmacology; D006689:Hodgkin Disease / Q000276:immunology* / Q000473:pathology; D006801:Humans; D006825:Hybridomas; D000922:Immunotoxins / Q000494:pharmacology*; D017730:Ki-1 Antigen / Q000276:immunology* / Q000627:therapeutic use; D010446:Peptide Fragments; D011549:Pseudomonas; D011993:Recombinant Fusion Proteins / Q000235:genetics*; D016539:Reed-Sternberg Cells / Q000187:drug effects / Q000276:immunology*; D014407:Tumor Cells, Cultured
D001427:Bacterial Toxins; D005098:Exotoxins; D000922:Immunotoxins; D017730:Ki-1 Antigen; D010446:Peptide Fragments; D011993:Recombinant Fusion Proteins