Engineering Approaches in Plant Molecular Farming for Global Health.

Tsepo Lebiletsa Tsekoa,Advaita Acarya Singh,Priyen Pillay

doi:10.3390/vaccines9111270

Tsepo Lebiletsa Tsekoa, Advaita Acarya Singh + Show 1 more

Open Access

https://doi.org/10.3390/vaccines9111270

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Journal: Vaccines	Publication Date: Nov 3, 2021
Citations: 6	License type: CC BY 4.0

Affiliation: Council for Scientific and Industrial Research

Abstract

Since the demonstration of the first plant-produced proteins of medical interest, there has been significant growth and interest in the field of plant molecular farming, with plants now being considered a viable production platform for vaccines. Despite this interest and development by a few biopharmaceutical companies, plant molecular farming is yet to be embraced by ‘big pharma’. The plant system offers a faster alternative, which is a potentially more cost-effective and scalable platform for the mass production of highly complex protein vaccines, owing to the high degree of similarity between the plant and mammalian secretory pathway. Here, we identify and address bottlenecks in the use of plants for vaccine manufacturing and discuss engineering approaches that demonstrate both the utility and versatility of the plant production system as a viable biomanufacturing platform for global health. Strategies for improving the yields and quality of plant-produced vaccines, as well as the incorporation of authentic posttranslational modifications that are essential to the functionality of these highly complex protein vaccines, will also be discussed. Case-by-case examples are considered for improving the production of functional protein-based vaccines. The combination of all these strategies provides a basis for the use of cutting-edge genome editing technology to create a general plant chassis with reduced host cell proteins, which is optimised for high-level protein production of vaccines with the correct posttranslational modifications.

Highlights

Vaccination has been the most effective intervention in reducing death and morbidity resulting from infectious diseases in the last century
Recombinant protein expression stresses the machinery, and by doing so, induces the unfolded protein response (UPR), which results in an increase in chaperone expression
A similar approach can be adopted in Nicotiana spp.; since Polyphenol oxidases (PPOs) function in defence, elimination of PPO activity may interfere with normal plant growth and phenotypic properties

Summary

Introduction

Vaccination has been the most effective intervention in reducing death and morbidity resulting from infectious diseases in the last century. Traditional recombinant protein production approaches used are microbial fermentation, mammalian and insect cell culture, and transgenic animals. These systems have their drawbacks concerning upfront capital costs, scalability, and recombinant protein safety and authenticity [2,3,4]. The high deg2reoef 1o1f similarity between the plant and mammalian secretory pathways makes it possible to efficiently produce highly complex protein-based vaccines [10]. One of the desired outcomes in molecular farming is to achieve a high-expression yield of recombinant protein. To achieve high-expression yields of recombinant proteins, expression constructs must be optimized at all stages, from transcript to protein stability. The p19 suppressor from tomato bushy stunt virus (TBSV) is perhaps the most well studied and functions by binding siRNA and prevents RISC assembly, thereby increasing recombinant protein yields [37]

Modulation of Chaperone Expression

Modulation of Endogenous Oxidase Activity

Limiting in Planta Proteolytic Degradation

Tyrosine O-Sulfation of Plant-Produced Vaccines

Findings

Conclusions and Future