Prevention of severe COVID-19 disease by SARS-CoV-2 in high-risk patients, such as immuno-compromised individuals, can be achieved by administration of antibody prophylaxis, but producing antibodies can be costly. Plant expression platforms allow substantial lower production costs compared to traditional bio-manufacturing platforms depending on mammalian cells in bioreactors. In this study, we describe the expression, production and purification of the originally human COVA2-15 antibody in plants. Our plant-produced mAbs demonstrated comparable neutralizing activity with COVA2-15 produced in mammalian cells. Furthermore, they exhibited similar capacity to prevent SARS-CoV-2 infection in a hamster model. To further enhance these biosimilars, we performed three glyco- and protein engineering techniques. First, to increase antibody half-life, we introduced YTE-mutation in the Fc tail; second, optimization of N-linked glycosylation by the addition of a C-terminal ER-retention motif (HDEL), and finally; production of mAb in plant production lines lacking β-1,2-xylosyltransferase and α-1,3-fucosyltransferase activities (FX-KO). These engineered biosimilars exhibited optimized glycosylation, enhanced phagocytosis and NK cell activation capacity compared to conventional plant-produced S15 and M15 biosimilars, in some cases outperforming mammalian cell produced COVA2-15. These engineered antibodies hold great potential for enhancing in vivo efficacy of mAb treatment against COVID-19 and provide a platform for the development of antibodies against other emerging viruses in a cost-effective manner.

中文翻译：

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植物生产的 SARS-CoV-2 抗体，旨在提高效力和体内功效


可以通过抗体预防来预防高危患者（例如免疫功能低下个体）中 SARS-CoV-2 预防严重的 COVID-19 疾病，但产生抗体的成本可能很高。与依赖于生物反应器中哺乳动物细胞的传统生物制造平台相比，植物表达平台可显著降低生产成本。在本研究中，我们描述了原始人 COVA2-15 抗体在植物中的表达、生产和纯化。我们的植物源 mAb 显示出与哺乳动物细胞中产生的 COVA2-15 相当的中和活性。此外，它们在仓鼠模型中表现出相似的预防 SARS-CoV-2 感染的能力。为了进一步增强这些生物仿制药，我们进行了三种糖和蛋白质工程技术。首先，为了增加抗体半衰期，我们在 Fc 尾部引入了 YTE 突变;其次，通过添加 C 端 ER 保留基序 （HDEL） 来优化 N-连接糖基化，最后;在缺乏 β-1,2-木糖基转移酶和 α-1,3-岩藻糖基转移酶活性 （FX-KO） 的植物生产线中生产 mAb。与传统的植物生产的 S15 和 M15 生物仿制药相比，这些工程生物仿制药表现出优化的糖基化、增强的吞噬作用和 NK 细胞活化能力，在某些情况下优于哺乳动物细胞产生的 COVA2-15。这些工程抗体在提高 mAb 治疗 COVID-19 的体内疗效方面具有巨大潜力，并为以经济高效的方式开发针对其他新兴病毒的抗体提供了一个平台。