Cloning of Bovine Interferon-gamma Gene and Its Expression in COS-1 Cells

Bovine interferon-gamma(BovIFN-γ) gene with signal peptide encoding region was amplified by reverse transcription polymerase chain reaction (RT-PCR) from total RNA of bovine peripheral blood lymphocytes stimulated with phytohemagglutinin (PHA). The products of RT-PCR were cloned into PMD18-T vector. Postive recombinant clone named BovIFN-γ-T4 was identified by restriction enzyme digestion and sequencing. The fragment of BovIFN-γin the PMD18-T vector was subcloned into mammalian expression vector pcDNA3.1, which was named with pcDNA-BovIFN-γ. Eukaryotic expression plasmid pcDNA-BovIFN-γwere transfected into COS-1 cells by lipofectin, rBovIFN-γexpression was identified in the cytoplasms and cytomembranes of COS-1 cells in IFA at 72 h posttransfection. The interferon titer in the supernatant of transfected COS-1 cells was up to 128 IU/mL. These results suggested that pcDNA-BovIFN-γcould be used to establish a cell line expressing rBovIFN-γstably, and rBovIFN-γ could be served as a new product in the control of bovine diseases.