[Construction and prokaryotic expression of a recombinant immunotoxin fused with mouse interleukin 18 and truncated Pseudomonas exotoxin].

OBJECTIVE: To construct a new recombinant immunotoxin expression vector by fusion of mouse interleukin 18 (mIL-18) gene and a truncated form of A (PE38) gene, and examine the expression of IL-18-PE38 fusion protein in Escherichia coli. METHODS: mIL-18 cDNA was cloned from mouse liver tissue through reverse transcription-polymerase chain reaction (RT-PCR). The mIL-18 cDNA was subcloned into a PE38 gene inserted fusion protein expression plasmid. The recombinant vector was identified by restriction endonucleases digestion, PCR and DNA sequencing. After transformed into E. coli BL21 and induced by IPTG, the expressed product was obtained and detected the molecular weight and specificity by SDS-PAGE and Western-blotting. RESULTS: The new recombinant immunotoxin expression vector was constructed successfully. The IL-18-PE38 fusion protein was expressed in E. coli BL21, and the molecular weight of the expression product was identical to the expected value. In addition, the protein expressed could react with the specific antibody against mIL-18. CONCLUSION: IL-18-PE38 recombinant immunotoxin expression vector will provide the basis for study on the targeted cytotoxic activity to Th1 cell and may have some potential value in the treatment of autoimmune disease and T cell leukemias.