Biomanufacturing of protective antibodies and other therapeutics in edible plant tissues for oral applications

[EN] Although plant expression systems used for production of therapeutic proteins have the advantage of being scalable at a low price, the downstream processing necessary to obtain pure therapeutic molecules is as expensive as for the traditional Chinese hamster ovary (CHO) platforms. However, when edible plant tissues (EPTs) are used, there is no need for exhaustive purification, because they can be delivered orally as partially purified formulations that are safe for consumption. This economic benefit is especially interesting when high doses of recombinant proteins are required throughout the treatment/prophylaxis period, as is the case for antibodies used for oral passive immunization (OPI). The secretory IgA (SIgA) antibodies, which are highly abundant in the digestive tract and mucosal secretions, and thus the first choice for OPI, have only been successfully produced in plant expression systems. Here, we cover most of the up-todate examples of EPT-produced pharmaceuticals, including two examples of SIgA aimed at oral delivery. We describe the benefits and drawbacks of delivering partially purified formulations and discuss a number of practical considerations and criteria to take into account when using plant expression systems, such as subcellular targeting, protein degradation, glycosylation patterns and downstream strategies, all crucial for improved yield, high quality and low cost of the final product.The authors would like to thank Annick Bleys for assistance with the manuscript preparation. P.J. would like to express gratitude towards the Spanish Ministry of Economy and Competiveness for her FPU fellowship and towards the International Society for Plant Molecular Farming for their generous bursaries for attending the PBVAB 2015. This work was supported by grants from Research Foundation Flanders (FWO project G0C9714N), from the European Commission (H2020-MSCA-IF-2014 Proposal 658701-ImmunoFarm) and from the Spanish Ministry of Economy and Competiveness (Plan Nacional I+D Grant BIO2013-42193R).Juarez, P.; Virdi, V.; Depicker, A.; Orzáez Calatayud, DV. (2016). Biomanufacturing of protective antibodies and other therapeutics in edible plant tissues for oral applications. Plant Biotechnology Journal. 14(9):1791-1799. https://doi.org/10.1111/pbi.12541S1791179914