Construction of viral-based expression vectors for high-level production of human interferon alpha 2b in plants

Human interferon (hINF) alpha 2b is clinically important pharmaceutical product included in combinatory therapy against chronic hepatitis C and B and complex therapy against several cancer diseases. Here, we created the genetic constructions, based on genome elements of potato virus X (PVX), carrying the infα2b gene for transient expression in plant cells. The created plasmid vector constructions were tested through Agrobacterium-mediated transient gene expression method in two plant species-Nicotiana benthamiana and Ocimum basilicum (sweet basil). Production of recombinant hINF alpha 2b was more efficient in N. benthamiana than that in O. basilicum plants. The average yield of hINF alpha 2b produced in N. benthamiana plants was 0.56 mg/g of fresh leaf weight (FW) or 6% of the total soluble cell proteins (TSP). The maximal level reached up to 1.2 mg/g FW or 9% TSP. We estimated that about 0.67 mg of hINF can be obtained from one N. benthamiana plant. The yield of hINF alpha 2b obtained with the PVX-based expression cassette was about 80 times higher than the yield of hINF alpha 2b obtained with a simple expression cassette in which the infα2b gene was controlled by the 35S promoter of cauliflower mosaic virus. KEY POINTS: • PVX-based expression vectors provide efficient transient expression of infα2b gene • N. benthamiana plants can produce human interferon alpha 2b at high levels • The yield of the hINF α2b reached up to 1.2 mg/g of fresh leaf weight.