High-level production of recombinant chicken interferon-gamma by Brevibacillus choshinensis

Cytokines, such as interferon-gamma have been shown to have adjuvant and gr owth promoting activity in poultry and livestock and have the potential to be used as alternatives to antibiotics. We have developed an efficient syst em for commercial-scale synthesis of recombinant chicken interferon-gamma ( ChIFN-gamma) using Brevibacillus choshinensis as the host for protein produ ction. The ChIFN-gamma expression vector, pNCIFN, was constructed using the novel Escherichia coli-B. choshinensis shuttle vector, pNCMO2. ChIFN-gamma expression was optimized by investigating different culture conditions and different host B. choshinensis mutants. The highest level of production wa s observed using the B. choshinensis HPD31-MB2 strain grown at 30 degreesC, where ChIFN-gamma was produced at approximately 300-500 mg/ L. ChIFN-gamma was also produced as a His-tagged fusion protein by using the pNCHis-IFN e xpression vector, a derivative of pNCMO2. The protein was constitutively se creted into the culture supernatant and could be partially purified in a si ngle step using a Ni-nitrilotriacetic acid column. This recombinant His-ChI FN-gamma was shown to have the same biological activity as native ChIFN-gam ma. (C) 2001 Academic Press.