[Expression of a novel human interleukin-13 in E.coli and its biological activity assay].

AIM: To express a novel Gln98-deleted human interleukin-13 in E.coli. METHODS: Total RNA was isolated from Jurkat cells costimulated with PHA and ConA. A 358 bp-specific DNA fragment encoding hIL-13 was amplified by semi-nested RT-PCR. DNA sequencing showed that the target DNA was a Gln98-deleted novel splicing of hIL-13. This hIL-13 cDNA and plasmid pBV220 were ligated at BamH I and EcoR I sites to construct the expression vector. After transforming E.coli strain DH5alpha, the expression of the novel splicing hIL-13 gene was induced by shifting culture temperature from 30 degrees Celsius to 42 degrees Celsius. The expression product was then purified by chromatography on Sepharcryl-200 gel column, and the bioactivity was detected by MTT colorimetry on the growth of TF-1 cell line. RESULTS: The novel rhIL-13 was expressed in the form of inclusion bodies. After purification and renaturation, the specific activity of the novel rhIL-13 was 1.6x10(6) IU/mg. CONCLUSION: The novel rhIL-13 with biological activity has been obtained, which lays the foundation for treating cancer and septicemia by the cytokine in future.