利用纳米颗粒和聚焦超声等治疗设备的原位疫苗接种（ISV）可以触发对被治疗和未经治疗的肿瘤细胞的免疫介导杀伤。然而，年龄和肠道微生物组成等混杂因素对治疗结果的影响尚不清楚。本研究中，我们使用聚焦超声和钙调蛋白纳米颗粒（CRT-NP）顺序治疗年轻小鼠（~8周）和老年小鼠（>18个月）的双侧黑色素瘤，以增强免疫原性细胞死亡。与老年小鼠相比，CRT-NP和聚焦超声（CFUS）对年轻小鼠的治疗和未经治疗肿瘤的回归的疗效更显著。老年小鼠的治疗效果不佳与肠道菌群组成的显著差异有关，其特征是细菌种类和脾脏免疫细胞的改变。具体而言，接受CFUS治疗的年轻小鼠中Bacteroidetes和Verrucomicrobia的丰度较高，而老年小鼠中未观察到这种情况。在两个年龄组中，Turicibacter、Anaerotruncus和Ruminiclostridium与CD8+ T细胞呈负相关，与CD4+ T细胞和MDSC细胞呈正相关。通过分类集富集分析发现，与年轻集群相比，老年集群只有11个富集的宿主基因靶点。这些发现突显了ISV治疗效果和肠道微生物组成之间的关系，表明改变饮食、使用益生菌或进行粪菌移植等干预措施可能具有潜力，以增强对实体肿瘤的免疫反应。版权所有 © 2023. Elsevier Inc. 发布。

In-situ vaccination (ISV) utilizing nanoparticles (NPs) and therapeutic devices like focused ultrasound (FUS) can trigger immune-mediated killing of both treated and untreated cancer cells. However, the impact of confounding factors such as aging and gut microbiota composition on therapeutic outcomes remains poorly understood. In this study, we sequentially treated young mice (~8 weeks) and old mice (>18 months) with bilateral melanoma using FUS and calreticulin nanoparticles (CRT-NP) to enhance immunogenic cell death. The combination of CRT-NP and FUS (CFUS) demonstrated greater efficacy in inducing regression of treated and untreated tumors in young mice compared to old mice. The diminished effectiveness in older mice was associated with significant differences in gut microbiome composition, characterized by alterations in bacterial species and splenic immune cells. Specifically, young mice exposed to CFUS exhibited higher abundance of Bacteroidetes and Verrucomicrobia, which was not observed in the aged cohorts. Turicibacter, Anaerotruncus, and Ruminiclostridium demonstrated negative correlations with CD8+ T cells but positive correlations with CD4+ T cells and MDSC cells in both age groups. Taxon set enrichment analysis revealed 58 significantly enriched host gene targets in the young cluster compared to only 11 in the aged cluster. These findings highlight the relationship between ISV treatment efficacy and gut microbiome composition, suggesting that interventions such as diet modification, probiotics, or fecal microbiota transplantation may hold potential as therapeutic strategies to enhance immune responses against solid tumors.Copyright © 2023. Published by Elsevier Inc.