Expression of Human Papillomavirus Type 16 L1 Protein in Transgenic Tobacco Plants

Abstract

To develop a plant expression system for the production of the human papillomavirus type 16 (HPV16) vaccine, we investigated whether the HPV16 L1 protein can be expressed in tobacco plants and whether it can be used as the cheapest form of edible vaccine. The HPV16 L1 coding sequence was amplified by PCR using specific primers from the plasmid pGEM-T-HPV16 containing the template sequence, and subcloned into the intermediate vector pUCmT and binary vector pBI121 consecutively to obtain the plant expression plasmid pBI-L1. The T-DNA regions of the pBI-L1 binary vector contained the constitutive Cauliflower mosaic virus (CaMV) 35S promoter and the neomycin phosphotransferase npt II gene, which allowed the selection of transformed plants using kanamycin. The tobacco plants were transformed by cocultivating them, using the leaf disc method, with Agrobacterium tumefaciens LBA4404, which harbored the plant expression plasmid. The regenerated transgenic tobacco plants were selected using kanamycin, and confirmed by PCR. The results of the Southern blot assay also showed that the HPV16 L1 gene was integrated stably into the genome of the transformed tobacco plants. The Western blot analysis showed that the transformed tobacco leaves could express the HPV16 L1 protein. Furthermore, it was demonstrated by ELISA assay that the expressed protein accounted for 0.034%-0.076% of the total soluble leaf protein, was able to form 55 nm virus-like particles compatible with HPV virus-like particle (VLP), and induced mouse erythrocyte hemagglutination in vitro. The present results indicate that the HPV16 L1 protein can be expressed in transgenic tobacco plants and the expressed protein possesses the natural features of the HPV16 L1 protein, implying that the HPV16 L1 transgenic plants can be potentially used as an edible vaccine.

Human Papillomavirus Type 16 E5 Protein as a Therapeutic Target

“…The promising results generated in preclinical animal studies have led to phase I/II clinical trials using the HPV-16 VLP vaccine delivered intramuscularly. Recently, Liu et al49 showed that the HPV-16 L1 protein could be expressed in transgenic tobacco plants and that the expressed protein possessed the natural features of the HPV-16 L1 protein, implying that the HPV-16 L1 transgenic plants could potentially be used as an edible vaccine. These studies suggest the possibility of vaccinating large populations with the HPV VLPs without using syringes.…”

Enhanced conversion of plant biomass into glucose using transgenic rice-produced endoglucanase for cellulosic ethanol

“…Plants have been used as ''green bioreactors'' for the production of essential enzymes (Hong et al 2004;Chiang et al 2005) and other proteins (Liu et al 2005), carbohydrates (Sahrawy et al 2004) and lipids (Qi et al 2004) while requiring minimal inputs of raw materials and energy (Teymouri et al 2004). Production of biomolecules in plants, considered as molecular farming, is one approach to improve the economics and increase the lowcost production efficiency of these biomolecules (Fischer et al 2004).…”

Expression of Human Papillomavirus Type 16 Major Capsid Protein L1 in Transgenic Arabidopsis thaliana

“…Reports have suggested that transgenic plants that express antigens could be used for low-cost vaccine production systems, and a number of human viral antigens have now successfully been expressed in transgenic plants (Arntzen et al 1994;Mason and Arntzen 1995;McGarvey et al 1995;Richter et al 2000;Huang et al 2005;Liu et al 2005;Varsani et al 2006).…”