High expression of consensus dengue virus envelope glycoprotein domain III using a viral expression system in tobacco

Although plant-based vaccines have many advantages, their use is limited by low expression of antigen genes in transgenic plants, which results in low immune responses and immune tolerance. To overcome this problem, Nicotiana benthamiana was used to produce the consensus domain III of dengue virus envelope glycoprotein (E) via agroinfiltration with a plant virus-based expression system. The binding of E glycoprotein to a receptor is important for dengue virus entry into host cells and results in human disease. Consensus domain III of dengue virus E glycoprotein (cEDIII) is immunogenic and can elicit neutralizing antibodies against all four serotypes of dengue virus. A DNA fragment encoding cEDIII and M cell-targeting ligand fused to cEDIII (cEDIII-Co1) were constructed in a viral vector and introduced into tobacco plant cells by Agrobacterium-mediated infiltration. The cEDIII and cEDIII-Co1 fusion proteins were detected in protein extracts from agroinfiltrated leaves by Western blot analysis. The plant-produced cEDIII and cEDIII-Co1 fusion proteins composed 5.2 and 4.8 mg/g of dry weight of leaf tissues, respectively. These results suggest that the high expression of dengue virus cEDIII in plants with a plant virus-based expression system can overcome the low expression level to improve the feasibility of plant-based vaccines.