PD-1/PD-L1免疫检查点抑制剂目前是临床实践中最常用的药物，通过免疫刺激应答来对抗恶性肿瘤。但是，所有这些抑制剂目前都是使用抗体为基础的治疗以注射的方式给药，而口服替代品的需求不断增长。本研究通过合成具有低免疫原性的纳米复合物，将其包裹在外泌体中，能够通过口服吸收靶向PD-L1，并在体内激活抗肿瘤免疫反应。超级PD-L1外泌体（SuperPDL1exo）经过透射电镜（TEM）、动态光散射（DLS）、傅里叶变换红外（FTIR）、X射线光电子能谱（XPS）和凝胶银染色进行了表征。超级PD-L1外泌体的跨膜能力通过流式细胞仪和免疫荧光进行了评估。细胞活力使用细胞计数试剂盒-8（CCK-8）进行了测定。ELISA实验用于检测血清和组织炎症因子以及血清生化指标。组织切片使用H&E染色评估了超级PD-L1外泌体的安全性。在免疫功能完整的C57BL/6小鼠中建立了MC38结直肠癌模型，评估了超级PD-L1外泌体对体内肿瘤生长的影响。免疫组织化学（IHC）染色用于检测穿孔素和颗粒酶等细胞毒素因子。首先，成功合成了超级PD-L1，并通过超声波、反复冷冻-解冻循环和挤压将奶外泌体膜封装成超级PD-L1外泌体。多重表征结果证实了超级PD-L1外泌体纳米粒子的成功合成。此外，我们的数据表明，超级PD-L1外泌体表现出良好的胶体稳定性和优越的细胞穿膜能力。体外和体内实验表明，超级PD-L1外泌体不会对多个全身器官造成损伤，展示了其良好的生物相容性。最后，在MC38结直肠癌小鼠模型中发现，超级PD-L1外泌体能够抑制结直肠癌的进展，并且这种抑制肿瘤的效应是通过激活肿瘤特异性细胞毒性T淋巴细胞（CTL）相关的免疫反应介导的。本研究成功设计和合成了一种口服纳米治疗药物——超级PD-L1外泌体，该药物具有小颗粒大小、优良的胶体稳定性、在肿瘤细胞内的穿膜能力以及生物相容性。体内实验显示，它能有效激活T细胞免疫并发挥抗肿瘤效果。版权所有© 2023刘、王、游、马、孙、佘、何和杨。

PD-1/PD-L1 immune checkpoint inhibitors are currently the most commonly utilized agents in clinical practice, which elicit an immunostimulatory response to combat malignancies. However, all these inhibitors are currently administered via injection using antibody-based therapies, while there is a growing need for oral alternatives.This study has developed and synthesized exosome-wrapped gold-peptide nanocomplexes with low immunogenicity, which can target PD-L1 and activate antitumor immunity in vivo through oral absorption. The SuperPDL1exo was characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS), Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), and gel silver staining. The transmembrane ability of SuperPDL1exo was evaluated by flow cytometry and immunofluorescence. Cell viability was determined using the Cell Counting Kit-8 (CCK-8) assay. ELISA experiments were conducted to detect serum and tissue inflammatory factors, as well as serum biochemical indicators. Tissue sections were stained with H&E for the evaluation of the safety of SuperPDL1exo. An MC38 colon cancer model was established in immunocompetent C56BL/6 mice to evaluate the effects of SuperPDL1exo on tumor growth in vivo. Immunohistochemistry (IHC) staining was performed to detect cytotoxicity factors such as perforin and granzymes.First, SuperPDL1 was successfully synthesized, and milk exosome membranes were encapsulated through ultrasound, repeated freeze-thaw cycles, and extrusion, resulting in the synthesis of SuperPDL1exo. Multiple characterization results confirmed the successful synthesis of SuperPDL1exo nanoparticles. Furthermore, our data demonstrated that SuperPDL1exo exhibited excellent colloidal stability and superior cell transmembrane ability. In vitro and in vivo experiments revealed that SuperPDL1exo did not cause damage to multiple systemic organs, demonstrating its good biocompatibility. Finally, in the MC38 colon cancer mouse model, it was discovered that SuperPDL1exo could inhibit the progression of colon cancer, and this tumor-suppressive effect was mediated through the activation of tumor-specific cytotoxic T lymphocyte (CTL)-related immune responses.This study has successfully designed and synthesized an oral nanotherapeutic, SuperPDL1exo, which demonstrates small particle size, excellent colloidal stability, transmembrane ability in tumor cells, and biocompatibility. In vivo experiments have shown that it effectively activates T-cell immunity and exerts antitumor effects.Copyright © 2023 Liu, Wang, You, Ma, Sun, She, He and Yang.