CHU de Québec-Université Laval Research Center (Oncology division), Université Laval Cancer Research Center, Québec, Qc, Canada.
CHU de Québec-Université Laval Research Center (Oncology division), Université Laval Cancer Research Center, Québec, Qc, Canada; BioVec Pharma, Québec, Qc, Canada.
Virus Res. 2021 Apr 2;295:198305. doi: 10.1016/j.virusres.2021.198305. Epub 2021 Jan 19.
In this study, we showed that a codon optimized version of the spike (S) protein of SARS-CoV-2 can migrate to the cell membrane. However, efficient production of Moloney murine leukemia (MLV) infectious viral particles was only achieved with stable expression of a shorter S version in C-terminal (ΔS) in MLV Gag-pol expressing cells. As compared to transient transfections, this platform generated viruses with a 1000-fold higher titer. ΔS was 15-times more efficiently incorporated into VLPs as compared to S, and that was not due to steric interference between the cytoplasmic tail and the MLV capsid, as similar differences were also observed with extracellular vesicles. The amount of ΔS incorporated into VLPs released from producer cells was high and estimated at 1.25 μg/mL S2 equivalent (S is comprised of S1 and S2). The resulting VLPs could potentially be used alone or as a boost of other immunization strategies for COVID-19.
在这项研究中，我们表明，经过密码子优化的 SARS-CoV-2 刺突（S）蛋白可以迁移到细胞膜。然而，只有在 MLV Gag-pol 表达细胞中稳定表达较短的 S 蛋白 C 末端（ΔS）时，才能有效地产生 Moloney 鼠白血病（MLV）感染性病毒颗粒。与瞬时转染相比，该平台产生的病毒滴度提高了 1000 倍。与 S 相比，ΔS 被更有效地掺入到 VLPs 中，这不是由于细胞质尾与 MLV 衣壳之间的空间干扰，因为在细胞外囊泡中也观察到类似的差异。从产生细胞释放的 VLPs 中掺入的 ΔS 量很高，估计为 1.25 μg/mL S2 当量（S 由 S1 和 S2 组成）。由此产生的 VLPs 单独使用或作为其他 COVID-19 免疫策略的增强剂可能具有潜力。
