Genomics Research Center, Academia Sinica, Taipei 11529, Taiwan.
The Master Program of AI Application in Health Industry, Kaohsiung Medical University, Kaohsiung City 80708, Taiwan.
Proc Natl Acad Sci U S A. 2022 Mar 1;119(9). doi: 10.1073/pnas.2119995119.
Development of the messenger RNA (mRNA) vaccine has emerged as an effective and speedy strategy to control the spread of new pathogens. After vaccination, the mRNA is translated into the real protein vaccine, and there is no need to manufacture the protein in vitro. However, the fate of mRNA and its posttranslational modification inside the cell may affect immune response. Here, we showed that the mRNA vaccine of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein with deletion of glycosites in the receptor-binding domain (RBD) or especially the subunit 2 (S2) domain to expose more conserved epitopes elicited stronger antibody and CD8 T cell responses with broader protection against the alpha, beta, gamma, delta, and omicron variants, compared to the unmodified mRNA. Immunization of such mRNA resulted in accumulation of misfolded spike protein in the endoplasmic reticulum, causing the up-regulation of BiP/GRP78, XBP1, and p-eIF2α to induce cell apoptosis and strong CD8 T cell response. In addition, dendritic cells (DCs) incubated with S2-glysosite deleted mRNA vaccine increased class I major histocompatibility complex (MHC I) expression. This study provides a direction for the development of broad-spectrum mRNA vaccines which may not be achieved with the use of expressed proteins as antigens.
信使 RNA（mRNA）疫苗的开发已成为控制新病原体传播的一种有效且快速的策略。接种疫苗后，mRNA 被翻译成真正的蛋白质疫苗，而无需在体外制造蛋白质。然而，mRNA 在细胞内的命运及其翻译后的修饰可能会影响免疫反应。在这里，我们表明，严重急性呼吸综合征冠状病毒 2（SARS-CoV-2）刺突蛋白的 mRNA 疫苗在受体结合域（RBD）或特别是亚单位 2（S2）域中删除糖基化位点以暴露更多保守表位，与未修饰的 mRNA 相比，可引发更强的抗体和 CD8 T 细胞反应，并具有更广泛的针对 alpha、beta、gamma、delta 和 omicron 变体的保护作用。这种 mRNA 的免疫接种导致内质网中错误折叠的刺突蛋白积累，引起 BiP/GRP78、XBP1 和 p-eIF2α 的上调，从而诱导细胞凋亡和强烈的 CD8 T 细胞反应。此外，与 S2-糖基化位点缺失的 mRNA 疫苗孵育的树突状细胞（DC）增加了 I 类主要组织相容性复合物（MHC I）的表达。这项研究为广谱 mRNA 疫苗的开发提供了一个方向，而使用表达的蛋白质作为抗原可能无法实现这一目标。
