Construction and Expression of Novel Immunotoxin cpIL-4(13D)-PE38KDEL with Increased Activity

摘要

Interleukin-4 receptors(IL-4Rs)are expressed on a wide variety of human cancer cells,and therefore it may be a good option to treat IL-4R-bearing tumors with IL-4-fusing immunotoxins.In this study,the gene encoding human inter-leukin-4 mutein cpIL-4(13D)was obtained through overlapping polymerase chain reaction.A chimeric immunotoxin was constructed by genetically fusing the mutein cpIL-4(13D)to a modified version of Pseudomonas exotoxin A(PE38KDEL)and was expressed in Escherichia coli AD494(DE3).The expression level of the fusion protein was about 30% of the total bacterial protein assessed by SDS-PAGE analysis.After purification by affinity chromatography and anion exchange chro-matography,the chimeric protein was tested for its cytotoxicity.Our data show that cpIL-4( 13D)-PE38KDEL has improved cytotoxicity on IL-4R-bearing tumor cells in comparison with other IL-4-fusing immunotoxins and might be useful in treating tumors with a large number of IL-4Rs.