Cloning and Expression of Bovine Interleukin-15 in Escherichia coli

According to the sequence of IL-15 gene available on GenBankTM,a pair of primers was designed to amplify the full-length IL-15 gene by RT-PCR from peripheral blood lymphocyte stimulated by LPS and ConA.The full-length IL-15 gene was cloned into the pMD18-T vector.Identification by digestion with restriction endonuclease,PCR amplification and sequencing indicated the IL-15 gene was cloned successfully.The gene of mature IL-15 was amplified by PCR using the full-length gene as template and then inserted into the prokaryotic expressing vector pET-32a to construct pET-IL-15/BL21(DE3).After the bacteria were induced by IPTG,the target gene was expressed in the form of inclusion body with the fusion protein relative molecular mass 33 000.Expressed protein was purified by affinity chromatography.The result of Western-blot demonstrated that the recombinant fusion protein 6×His-IL-15 can be recognized by anti-6×His monoclonal antibody and anti-porcine IL-15 polyclonal antibodis.