Department of Chemical & Biomolecular Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea.
Department of Surgery-Transplant and Mary & Dick Holland Regenerative Medicine Program, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska 68198-5940, United States.
ACS Appl Mater Interfaces. 2022 Mar 9;14(9):11124-11143. doi: 10.1021/acsami.1c24982. Epub 2022 Feb 28.
Antigen delivery through an oral route requires overcoming multiple challenges, including gastrointestinal enzymes, mucus, and epithelial tight junctions. Although each barrier has a crucial role in determining the final efficiency of the oral vaccination, transcytosis of antigens through follicle-associated epithelium (FAE) represents a major challenge. Most of the research is focused on delivering an antigen to the M-cell for FAE transcytosis because M-cells can easily transport the antigen from the luminal site. However, the fact is that the M-cell population is less than 1% of the total gastrointestinal cells, and most of the oral vaccines have failed to show any effect in clinical trials. To challenge the current dogma of M-cell targeting, in this study, we designed a novel tandem peptide with a FAE-targeting peptide at the front position and a cell-penetrating peptide at the back position. The tandem peptide was attached to a smart delivery system, which overcomes the enzymatic barrier and the mucosal barrier. The result showed that the engineered system could target the FAE (enterocytes and M-cells) and successfully penetrate the enterocytes to reach the dendritic cells located at the subepithelium dome. There was successful maturation and activation of dendritic cells in vitro confirmed by a significant increase in maturation markers such as CD40, CD86, presentation marker MHC I, and proinflammatory cytokines (TNF-α, IL-6, and IL-10). The in vivo results showed a high production of CD4 T-lymphocytes (helper T-cell) and a significantly higher production of CD8 T-lymphocytes (killer T-cell). Finally, the production of mucosal immunity (IgA) in the trachea, intestine, and fecal extracts and systemic immunity (IgG, IgG1, and IgG2a) was successfully confirmed. To the best of our knowledge, this is the first study that designed a novel tandem peptide to target the FAE, which includes M-cells and enterocytes rather than M-cell targeting and showed that a significant induction of both the mucosal and systemic immune response was achieved compared to M-cell targeting.
经口服途径递送抗原需要克服多种挑战，包括胃肠道酶、黏液和上皮紧密连接。尽管每个屏障在决定口服疫苗的最终效率方面都起着至关重要的作用，但抗原通过滤泡相关上皮 (FAE) 的转胞吞作用是一个主要挑战。大多数研究都集中在将抗原递送到 M 细胞以进行 FAE 转胞吞作用上，因为 M 细胞可以轻易地将抗原从腔室部位转运出去。然而，事实是 M 细胞群体不到胃肠道细胞总数的 1%，并且大多数口服疫苗在临床试验中都未能显示出任何效果。为了挑战当前关于 M 细胞靶向的教条，在这项研究中，我们设计了一种新型串联肽，其前位带有 FAE 靶向肽，后位带有细胞穿透肽。串联肽与一种智能递药系统相连，该系统克服了酶屏障和黏膜屏障。结果表明，该工程系统可以靶向 FAE（肠上皮细胞和 M 细胞）并成功穿透肠上皮细胞，到达位于黏膜下层穹顶的树突状细胞。体外实验证实树突状细胞成功成熟和激活，其成熟标志物如 CD40、CD86、呈递标志物 MHC I 和前炎症细胞因子（TNF-α、IL-6 和 IL-10）显著增加。体内实验结果表明 CD4 T 淋巴细胞（辅助性 T 细胞）的大量产生和 CD8 T 淋巴细胞（杀伤性 T 细胞）的显著增加。最后，成功证实了气管、肠道和粪便提取物中的黏膜免疫（IgA）和系统免疫（IgG、IgG1 和 IgG2a）的产生。据我们所知，这是第一项设计新型串联肽靶向 FAE 的研究，该研究包括 M 细胞和肠上皮细胞，而不仅仅是 M 细胞靶向，并表明与 M 细胞靶向相比，黏膜和系统免疫反应都得到了显著诱导。
