S. Barth et al., Cl430L-ETA ': A new recombinant immunotoxin based on the CD30 ligand for possible use against human lymphoma, CYTOK CELL, 5(2), 1999, pp. 69-77
Recombinant DNA technology makes it possible to genetically fuse V genes or
cytokines to toxin domains, resulting in immunotherapeutics for selective
destruction of tumor cells. Since recombinant immunotoxins can be easily ma
nipulated in terms of affinity or cytotoxic potency and produced in large q
uantities, we have developed a new CD30 ligand-based fusion toxin (CD30L-ET
A'). Human CD30L cDNA was ligated into a pET-based expression plasmid and t
hereby fused to a modified Pseudomonas aeruginosa exotoxin A (ETA') lacking
its cell-binding domain I. After IPTG-indiced expression in E. coli strain
BL21(DE3), the 60 kDa His-tagged fusion protein (CD30L-ETA') was isolated
from inclusion bodies. Denatured protein was renatured in the presence of 0
.4 M arginine and a glutathione redox system. Refolded protein was purified
and concentrated by ion-exchange chromatography on a HiTrap Q column. The
binding properties of CD30L-ETA' were evaluated by competitive ELISA, immun
ohistochemical staining, and FACS analysis on CD30-expressing cells. The in
vitro toxicity of the fusion protein was then tested on the CD30(+) Hodgki
n-derived cell line L540cy and the Burkitt's lymphoma cell line BL38. CD30L
-ETA' exhibited specific cytotoxicity against L540cy cells (IC50 = 24 ng/ml
) as determined by [H-3]leucine uptake assays. This is the first report on
the specificity and cytotoxic potency of a chimeric CD30L fusion toxin agai
nst Hodgkin's disease-derived cells.