To use IL-2 and other cytokines for prevention and protection of diseases, suitable mass production technology needs to be developed. Among the baculovirus gene expression systems available, the most popular are the AcNPV/cell culture system, which is easy to handle and the BmNPV/silkworm system, which is expected to have high efficient production. Because baculoviruses have narrow host ranges, we could not use the same recombinant virus for both systems. This time we used a host range expanded hybrid baculovirus (HyNPV) developed in Japan. In the porcine IL-2 gene recombinant virus HyPIL2cp- infected TN5 cell culture fluid, 150 µg/ml of recombinant porcine IL-2 (rpoIL-2) was accumulated with few contaminant proteins. We inoculated the HyPIL2cp- to a silkworm cell line to confirm that the virus could work in the silkworm system. We then inoculated the virus to a 5th instar silkworm. The haemolymph of the silkworm after 4 days of infection contained about 2 mg/ml of biologically active rpoIL-2. We recovered 1mg of rpoIL-2 from one silkworm. For mass production, we inoculated this recombinant virus to 850 silkworms and recovered 500 ml of the haemolymph containing rpoIL-2. We concluded that the HyNPV/silkworm system is suitable for the mass production of livestock cytokines. (Associate Director, Department of Immunology TEL+81-298-38-7875)
References:
- Inumaru, S. et al.: High-efficient expression of porcine IL-2 with recombinant baculovirus infected silkworm, Bombyx mori. Biotechnol. Bioprocess Eng. 5: 146-149 (2000)
- Inumaru, S. et al.: Highly efficient expression of porcine IL-2 by hybrid baculovirus in silkworm. Cytokine 11: 958 (1999)
