Biosafety, Risk Assessment, and Regulation of Molecular Farming

Hundleby, Penny; Sack, Markus; Twyman, Richard M.

doi:10.1002/9781118801512.ch13

Cited by 7 publications

(4 citation statements)

References 72 publications

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“…The widespread adoption of plant-derived antibodies was initially discouraged by uncertainties in the regulatory framework, 159 differences in N-glycosylation between plants and humans 160 and the lack of large-scale manufacturing capacity. 161,162 Although antibodies are extremely versatile and useful at the laboratory scale, an important aspect for medical and industrial scientists as well as funding agencies is the need to advance plant-derived antibodies and green bionanomaterials into clinical trials and eventually into clinical practice.…”

Section: Translating Green Bionanomaterials Into Green Bionanomedicinesmentioning

confidence: 99%

Antibodies from plants for bionanomaterials

Edgue

Twyman²,

Beiss

et al. 2017

WIREs Nanomed Nanobiotechnol

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Antibodies are produced as part of the vertebrate adaptive immune response and are not naturally made by plants. However, antibody DNA sequences can be introduced into plants, and together with laboratory technologies that allow the design of antibodies recognizing any conceivable molecular structure, plants can be used as 'green factories' to produce any antibody at all. The advent of plant-based transient expression systems in particular allows the rapid, convenient, and safe production of antibodies, ranging from laboratory-scale expression to industrial-scale manufacturing. The key features of plant-based production include safety, speed, low cost, and convenience, allowing newcomers to rapidly master the technology and use it to its full advantage. Manufacturing in plants has recently achieved significant milestones and offers more than just an alternative to established microbial and mammalian cell platforms. The use of plants for product development in particular offers the power and flexibility to easily coexpress many different genes, allowing the plug-and-play construction of novel bionanomaterials, perfectly complementing existing approaches based on plant virus-like particles. As well as producing single antibodies for applications in medicine, agriculture, and industry, plants can be used to produce antibody-based supramolecular structures and scaffolds as a new generation of green bionanomaterials that promise a bright future based on clean and renewable nanotechnology applications. © 2017 The Authors. WIREs Nanomedicine and Nanobiotechnology published by Wiley Periodicals, Inc. How to cite this article:WIREs Nanomed Nanobiotechnol 2017, 9:e1462. doi: 10.1002/wnan.1462 INTRODUCTIONA ntibodies are glycoproteins produced by the adaptive immune system in humans and other vertebrates. They recognize and bind particular target antigens with great affinity and specificity, allowing them to clear pathogens and other unwanted material from the body. Although plants do not naturally produce antibodies, they can be engineered to do so by introducing the corresponding immunoglobulin genes. 1,2 In this manner, plants can be instructed to make antibodies that target any antigen of choice, and they can make them efficiently and in all kinds of different formats. 3,4 Most people picture antibodies as the typical mammalian serum-type immunoglobulin G (IgG), which comprises two identical heavy chains and two identical light chains joined by disulfide bonds (Figure 1). The chains fold and assemble into a multimeric Y-shaped structure. Below the hinge, in what is known as the Fc region (fragment crystallizable), all IgG molecules are largely the same, and this region is responsible for the general effector functions of antibodies, such as immune cell recognition and complement fixation. This part of the antibody is also glycosylated. The hinge and the region above, where the antibody branches into its characteristic Y-shape, is known as the F(ab 0 ) 2 or Fab (fragment for antigen This is an open access article under ...

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Section: Translating Green Bionanomaterials Into Green Bionanomedicinesmentioning

confidence: 99%

Antibodies from plants for bionanomaterials

Edgue

Twyman²,

Beiss

et al. 2017

WIREs Nanomed Nanobiotechnol

Self Cite

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“…The expression vector is generally cloned in Escherichia coli , so transient expression requires the transformation of E. coli and A. tumefaciens , resulting in two different genetically modified organisms (GMOs) [ 14 ]. The use of GMOs requires a formal risk assessment to quantify the hazard posed to personnel and the environment, and the likelihood of harm in practice [ 5 , 15 ]. Based on this assessment, GMOs are categorized and the precautions required for handling are defined, typically using four biosafety levels (BSLs), where BSL-1 encompasses non-pathogenic GMOs and BSL-2 covers agents with a moderate potential hazard [ 16 – 19 ].…”

Section: Introductionmentioning

confidence: 99%

Risk assessment and bioburden evaluation of Agrobacterium tumefaciens-mediated transient protein expression in plants using the CaMV35S promoter

Knödler,

Reunious,

Buyel

2023

BMC Biotechnol

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Large-scale transient expression of recombinant proteins in plants is increasingly used and requires the multi-liter cultivation of Agrobacterium tumefaciens transformed with an expression vector, which is often cloned in Escherichia coli first. Depending on the promoter, unintentional activity can occur in both bacteria, which could pose a safety risk to the environment and operators if the protein is toxic. To assess the risk associated with transient expression, we first tested expression vectors containing the CaMV35S promoter known to be active in plants and bacteria, along with controls to measure the accumulation of the corresponding recombinant proteins. We found that, in both bacteria, even the stable model protein DsRed accumulated at levels near the detection limit of the sandwich ELISA (3.8 µg L−1). Higher levels were detected in short cultivations (< 12 h) but never exceeded 10 µg L−1. We determined the abundance of A. tumefaciens throughout the process, including infiltration. We detected few bacteria in the clarified extract and found none after blanching. Finally, we combined protein accumulation and bacterial abundance data with the known effects of toxic proteins to estimate critical exposures for operators. We found that unintended toxin production in bacteria is negligible. Furthermore, the intravenous uptake of multiple milliliters of fermentation broth or infiltration suspension would be required to reach acute toxicity even when handling the most toxic products (LD50 ~ 1 ng kg−1). The unintentional uptake of such quantities is unlikely and we therefore regard transient expression as safe in terms of the bacterial handling procedure.

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“…After the Prodigene incident, in which transgenic maize plants were found growing in a soybean field, such relaxation seems much less likely (Hundleby, Sack, & Twyman, ).…”

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confidence: 99%

A simplified techno‐economic model for the molecular pharming of antibodies

Mir‐Artigues

Twyman

Alvarez

et al. 2019

Biotech & Bioengineering

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By the end of 2017, the Food and Drug Administration had approved a total of 77 therapeutic monoclonal antibodies (mAbs), most of which are still manufactured today. Furthermore, global sales of mAbs topped $90 billion in 2017 and are projected to reach $125 billion by 2020. The mAbs approved for human therapy are mostly produced using Chinese hamster ovary (CHO) cells, which require expensive infrastructure for production and purification. Molecular pharming in plants is an alternative approach with the benefits of lower costs, greater scalability, and intrinsic safety. For some platforms, the production cycle is also much quicker. But do these advantages really stack up in economic terms? Earlier techno-economic evaluations have focused on specific platforms or processes and have used different methods, making direct comparisons challenging and the overall benefits of molecular pharming difficult to gauge. Here, we present a simplified techno-economic model for the manufacturing of mAbs, which can be applied to any production platform by focusing on the most important factors that determine the efficiency and cost of bulk drug manufacturing. This model develops economic concepts to identify variables that can be used to achieve cost savings by simultaneously modeling the dynamic costs of upstream production at different scales and the corresponding downstream processing costs for different manufacturing modes (sequential, serial, and continuous). The use of simplified models will help to achieve meaningful comparisons between diverse manufacturing technologies. K E Y W O R D Sdownstream processing, protein manufacturing, techno-economic analysis, therapeutic antibodies, upstream production

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Biosafety, Risk Assessment, and Regulation of Molecular Farming

Cited by 7 publications

References 72 publications

Antibodies from plants for bionanomaterials

Antibodies from plants for bionanomaterials

Risk assessment and bioburden evaluation of Agrobacterium tumefaciens-mediated transient protein expression in plants using the CaMV35S promoter

A simplified techno‐economic model for the molecular pharming of antibodies

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