Koskela Essi V, de Ruijter Jorg C, Frey Alexander D
Department of Bioproducts and Biosystems, Aalto University, Espoo, Finland.
Current address: Department of Biocatalysis and Isotope Chemistry, Almac Sciences, Craigavon, Northern Ireland, United Kingdom.
Biotechnol J. 2017 Aug;12(8). doi: 10.1002/biot.201600631. Epub 2017 May 24.
Therapeutic protein production in yeast is a reality in industry with an untapped potential to expand to more complex proteins, such as full-length antibodies. Despite numerous engineering approaches, cellular limitations are preventing the use of Saccharomyces cerevisiae as the titers of recombinant antibodies are currently not competitive. Instead of a host specific approach, the possibility of adopting the features from native producers of antibodies, plasma cells, to improve antibody production in yeast. A subset of mammalian folding factors upregulated in plasma cells for expression in yeast and screened for beneficial effects on antibody secretion using a high-throughput ELISA platform was selected. Co-expression of the mammalian chaperone BiP, the co-chaperone GRP170, or the peptidyl-prolyl isomerase FKBP2, with the antibody improved specific product yields up to two-fold. By comparing strains expressing FKBP2 or the yeast PPIase Cpr5p, the authors demonstrate that speeding up peptidyl-prolyl isomerization by upregulation of catalyzing enzymes is a key factor to improve antibody titers in yeast. The findings show that following the route of plasma cells can improve product titers and contribute to developing an alternative yeast-based antibody factory.
在工业领域，利用酵母生产治疗性蛋白质已成为现实，并且具有扩展至生产更复杂蛋白质（如全长抗体）的未开发潜力。尽管有众多工程方法，但由于重组抗体的滴度目前缺乏竞争力，细胞的局限性阻碍了酿酒酵母的使用。与其采用针对特定宿主的方法，不如借鉴抗体天然生产者浆细胞的特性，以提高酵母中抗体的产量。选择了一组在浆细胞中上调的哺乳动物折叠因子，在酵母中表达，并使用高通量ELISA平台筛选其对抗体分泌的有益作用。将哺乳动物伴侣蛋白BiP、共伴侣蛋白GRP170或肽基脯氨酰异构酶FKBP2与抗体共表达，可使特定产物产量提高两倍。通过比较表达FKBP2或酵母肽基脯氨酰异构酶Cpr5p的菌株，作者证明上调催化酶以加速肽基脯氨酰异构化是提高酵母中抗体滴度的关键因素。研究结果表明，遵循浆细胞的途径可以提高产物滴度，并有助于开发一种基于酵母的替代抗体工厂。
