Special Issue "Plant-Derived Pharmaceuticals by Molecular Farming"

Guest Editor
Prof. Dr. Chang Won Choi
Department of Biology & Medicinal Science, Pai Chai University, Daejeon 302-735, Korea
E-Mail:
Phone: +8242 520 5617
Fax: +8242 520 5380
Interests: plant-derived biomedicines; plant-made pharmaceuticals; molecular farming; recombinant proteins; plant metabolic engineering; hypoglycaemic; hypolipidemic; antioxidants; antiviral

Dear Colleagues,

This special issue is aimed at both the basic and applied sciences of Plant Molecular Farming (PMF). PMF is the growing and harvesting of genetically engineered crops of transgenic plants, to produce biopharmaceuticals or industrial compounds instead of food, feed, or fibre. The possibilities cover from the manufacture of medical products, such as pharmaceuticals (drugs) and vaccines, to the products of industrial purpose like biodegradable plastics. The advantages of PMF in terms of production scale and economy, product safety, ease of storage and distribution are superior than any current commercial system. Despite the promising benefits, the commercialization of plant-derived pharmaceutical products is lagging by the uncertainty, particularly with regard to the adaptation of good manufacturing practice regulations to field-grown plants. Although it is not yet routinely commercialized, interest and investment in PMF are extending rapidly. PMF will be progressed for the core commercial development in biotechnology. Licensing of full scale production is forthcoming, although cultivated area in field will be very limited and highly regulated, or the initial stage of cultivation may begin in controlled greenhouses. The objective of this special issue is to provide high quality research results on novel gene expression in plants and its industrial or clinical application. I wish to thank all the authors for their contribution to this special issue.

Prof. Dr. Chang Won Choi
Guest Editor

Submission

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• edible vaccines
• antibodies for diagnostic, preventative, and therapeutic applications
• bioplastics made from simple, biodegradable molecules produced in plants
• an enzyme used in the treatment of human and animals
• enzymes for use in food processing
• proteins for industrial purpose

Type of Paper: Article
Title: Expression and Purification of Elastin-Like Polypeptide Fusion Influenza H5N1 Antigens in Nicotiana tabacum by Membrane Based-Inverse Transition Cycling
Authors: Hoang Trong Phan and Udo Conrad
Affiliation: Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstrasse 3, D-06466 Gatersleben, Germany;
E-Mail: conradu@ipk-gatersleben.de (U.C.)
Abstract: The H5N1 avian influenza A virus, commonly called “bird flu”, is a highly contagious and deadly pathogen in poultry. Furthermore, H5N1 influenza viruses transmitted from poultry to humans in Asia cause high mortality (289/489) and pose a pandemic threat. Vaccination is the most effective approach to reduce illness and death from pandemic influenza. Influenza vaccines (inactivated and live attenuated influenza vaccines) in general use today are derived from viruses grown in hens’ eggs. In reality, the H5N1 virus was highly pathogenic for poultry and also lethal for hen’s eggs. Therefore, the HA content of the H5N1 candidate vaccine viruses grown in embryonated chicken eggs was low. Plant expression systems are attractive because they offer a number of potential advantages: inexpensiveness; safety; ability of a rapid, economical scale-up. The most disadvantages of these expression systems are low concentration of recombinant proteins and the lack of efficient purification methods for recovering these proteins have hindered the availability of recombinant proteins in market. Elastin-like polypeptides (ELPs) are artificial biopolymers consisting of repeats of the pentapeptide sequence Val-Pro-Gly-Xaa-Gly (VPGXG), where Xaa is any amino acid except Pro. ELP fusion proteins can be easily purified by inverse transition cycling (ITC) depending on temperature and sodium chloride concentration. In this study, ELP was fused to different avian influenza H5N1 antigens and expressed in transgenic tobacco plants. Fusions with the ELP tag significantly enhance the accumulation of recombinant influenza antigens in tobacco leaves. A simple and scalable membrane-based ITC was developed and applied to recover the ELP fusion influenza antigens from leaf extracts.

Type of Paper: Article
Title: Transient Co-Expression of Post-Transcriptional Gene Silencing Suppressors Increased in planta Expression of a Recombinant Anthrax Receptor Fusion Protein
Authors: Lucas Arzola ¹, Junxing Chen ¹, Kittipong Rattanaporn ¹, James M. Maclean ² and Karen A. McDonald ¹
Affiliations: ¹ Department of Chemical Engineering & Materials Science, University of California, Davis, CA 94533, USA;
E-Mail: kamcdonald@ucdavis.edu (K.A.M.)
² Planet Biotechnology, Inc., 25571 Clawiter Road Hayward, CA 94545, USA
Abstract: Molecular farming of tobacco provides a rapid, scalable, and cost-effective alternative for production of pharmaceutical proteins. We have developed a transient production platform for a novel anthrax receptor decoy protein (immunoadhesin), PBI-220, in Nicotiana benthamiana. We evaluated, in intact plants and detached leaves, the co-expression of PBI-220 with nine different viral suppressors of post-transcriptional gene silencing (PTGS): p1, p10, p19, p21, p24, p25, p38, 2b, and HCPro. Overall, transient PBI-220 expression was higher on intact plants than detached leaves. It was observed to be highest with p1 co-expression at 3.5 days, resulting in a maximum production of 0.56 g PBI-220 per kg fresh weight of leaf. Co-expression with certain PTGS suppressors - particularly p1, p19, and p21 - significantly increased PBI-220 expression levels.