不变型自然杀伤T细胞（iNKT）是一种天然样T细胞，在肝窦中丰富，并在肿瘤免疫中发挥重要作用，但iNKT在胰腺癌肝转移（PCLM）中的作用尚未完全探索。本研究采用半脾胰腺肿瘤细胞注射的PCLM小鼠模型，该模型紧密模仿人类的临床情况，以探讨iNKT在PCLM中的作用。通过α-半乳糖酰胺（α-GC）活化iNKT细胞，显著增加免疫细胞浸润并抑制了PCLM的进展。通过单细胞RNA测序（scRNA-seq），我们对正常肝脏和PCLM中的30,000多个免疫细胞进行了分析，并能够表征治疗α-GC后肿瘤微环境中免疫细胞的全局变化，共鉴定了12个亚群。在α-GC治疗下，scRNA-Seq和流式细胞术分析显示iNKT / NK细胞的细胞毒性活性增强，并使CD4T细胞向细胞毒性Th1型倾斜，CD8T细胞向细胞毒性倾斜，表现出更高的增殖和减少疲劳标记PD1表达的特点。此外，α-GC治疗排除了肿瘤相关巨噬细胞。最后，成像质谱细胞术分析揭示了降低的上皮间质转化相关标志物和α-GC治疗的PCLM中活性CD4和CD8T细胞的增加。总的来说，我们的发现揭示了激活的iNKT细胞通过增加NK和T细胞免疫力和减少肿瘤相关巨噬细胞，在胰腺癌肝转移中的保护功能。Copyright © 2023 Elsevier B.V.发布。

Invariant natural killer T (iNKT) cells are innate-like T cells that are abundant in liver sinusoids and play a critical role in tumor immunity. However, the role of iNKT cells in pancreatic cancer liver metastasis (PCLM) has not been fully explored. In this study, we employed a hemi-spleen pancreatic tumor cell injection mouse model of PCLM, a model that closely mimics clinical conditions in humans, to explore the role of iNKT cells in PCLM. Activation of iNKT cells with α-galactosylceramide (αGC) markedly increased immune cell infiltration and suppressed PCLM progression. Via single cell RNA sequencing (scRNA-seq) we profiled over 30,000 immune cells from normal liver and PCLM with or without αGC treatment and were able to characterize the global changes of the immune cells in the tumor microenvironment upon αGC treatment, identifying a total of 12 subpopulations. Upon treatment with αGC, scRNA-Seq and flow cytometry analyses revealed increased cytotoxic activity of iNKT/NK cells and skewing CD4 T cells towards a cytotoxic Th1 profile and CD8 T cells towards a cytotoxic profile, characterized by higher proliferation and reduced exhaustion marker PD1 expression. Moreover, αGC treatment excluded tumor associated macrophages. Lastly, imaging mass cytometry analysis uncovered the reduced epithelial to mesenchymal transition related markers and increased active CD4 and CD8 T cells in PCLM with αGC treatment. Overall, our findings uncover the protective function of activated iNKT cells in pancreatic cancer liver metastasis through increased NK and T cell immunity and decreased tumor associated macrophages.Copyright © 2023. Published by Elsevier B.V.