Department of Biotechnology and Life Sciences, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Nakamachi, Koganei-shi, Tokyo 184-8588, Japan.
Department of Biochemistry and Molecular Biology, University of Chittagong, Chittagong 4331, Bangladesh.
Mol Pharm. 2020 May 4;17(5):1629-1637. doi: 10.1021/acs.molpharmaceut.0c00071. Epub 2020 Apr 21.
Subvisible aggregates of proteins are suspected to cause adverse immune response, and a recent FDA guideline has recommended the monitoring of micrometer-sized aggregates (2-10 μm) though recognizing that the underlying mechanism behind aggregation and immunogenicity remains unclear. Here, we report a correlation between the immunogenicity and the size of nanometer-scaled aggregates of a small 6.5 kDa model protein, bovine pancreatic trypsin inhibitor (BPTI) variant. BPTI-19A, a monomeric and nonimmunogenic protein, was oligomerized into subvisible aggregates with hydrodynamic radii () of 3-4 nm by attaching hydrophobic solubility controlling peptide (SCP) tags to its C-terminus. The results showed that the association of nonimmunogenic BPTI into nanometer-sized subvisible aggregates made it highly immunogenic, as assessed by the IgG antibody titers of the mice's sera. Overall, the study emphasizes that subvisible aggregates, as small as a few nanometers, which are presently ignored, are worth monitoring for deciphering the origin of undesired immunogenicity of therapeutic proteins.
疑似蛋白质亚可见聚集物会引起不良免疫反应，最近 FDA 指南建议监测微米级聚集物（2-10 μm），尽管认识到聚集和免疫原性背后的潜在机制仍不清楚。在这里，我们报告了一种小的 6.5 kDa 模型蛋白，牛胰蛋白酶抑制剂（BPTI）变体的纳米级聚集物的免疫原性与其尺寸之间的相关性。BPTI-19A 是一种单体且无免疫原性的蛋白质，通过在其 C 末端连接疏水性溶解度控制肽（SCP）标签，将其寡聚化为具有 3-4 nm 水动力半径（）的亚可见聚集物。结果表明，将无免疫原性的 BPTI 缔合为纳米级亚可见聚集物，使它具有高度的免疫原性，这可以通过小鼠血清中的 IgG 抗体滴度来评估。总的来说，这项研究强调，目前被忽视的小至数纳米的亚可见聚集物值得监测，以揭示治疗性蛋白质产生不良免疫原性的原因。
