Bacterial immunotherapy leveraging IL-10R hysteresis for both phagocytosis evasion and tumor immunity revitalization [CUT&Tag 2]. Bacterial immunotherapy leveraging IL-10R hysteresis for both phagocytosis evasion and tumor immunity revitalization [CUT&Tag 2]

Bacterial immunotherapy holds promising cancer-fighting potential. However, unlocking its power requires a mechanistic understanding of how bacteria both evade antimicrobial immune defenses and stimulate antitumor immune responses within the tumor microenvironment (TME). Here, by harnessing an engineered Salmonella enterica strain with this dual proficiency, we unveiled a singular mechanism underlying. Specifically, the hysteretic nonlinearity of interleukin-10 receptor (IL-10R) expression drives tumor-infiltrated immune cells into a tumor-specific IL-10Rhi state. Bacteria leverage this to enhance tumor-associated macrophages producing IL-10, evade phagocytosis by tumor-associated neutrophils, and coincidently expand and stimulate the preexisting exhausted tumor-resident CD8+ T cells. This effective combination eliminated tumors, prevented recurrence, and inhibited metastasis across multiple tumor types. Analysis of human samples suggested that IL-10Rhi state might be a ubiquitous trait across human tumor types. Our study unveils the unsolved mechanism behind bacterial immunotherapy's dual challenge in solid tumors and provides a framework for intratumor immunomodulation. Overall design: Jurkat T cells were divided into four groups: Pre-exposure (direct sample collection), Initial exposure (stimulated with 10 ng/ml IL-10 for 6 h), Rest (stimulated with 10 ng/ml IL-10 for 6 h, washed, and cultured for 48 h in 0.5 ng/ml IL-10 with medium changes every 12 h), and Subsequent exposure (same as Rest, with an additional 6-h stimulation with 10 ng/ml IL-10)

细菌免疫疗法（bacterial immunotherapy）具有极具前景的抗肿瘤潜力。然而，要充分释放其功效，需阐明细菌在肿瘤微环境（tumor microenvironment, TME）中如何同时逃逸抗菌免疫防御、激活抗肿瘤免疫应答的机制。本研究利用具备上述双重功能的工程化肠炎沙门氏菌（Salmonella enterica）菌株，揭示了其背后独特的作用机制。具体而言，白细胞介素-10受体（interleukin-10 receptor, IL-10R）表达的滞后非线性特征，可将肿瘤浸润免疫细胞诱导为肿瘤特异性IL-10R高表达（IL-10Rhi）状态。细菌可利用这一特征，促进肿瘤相关巨噬细胞分泌白细胞介素-10（interleukin-10, IL-10），逃逸肿瘤相关中性粒细胞的吞噬作用，同时扩增并激活预先存在的耗竭性肿瘤驻留CD8+ T细胞。该有效策略可在多种肿瘤模型中清除实体瘤、预防复发并抑制转移。对人类样本的分析显示，IL-10Rhi状态可能是多种人类肿瘤共有的特征。本研究阐明了细菌免疫疗法在实体瘤中面临双重挑战的未解机制，并为瘤内免疫调节提供了理论框架。实验整体设计：将Jurkat T细胞分为四组：① 预暴露组（直接收集样本）；② 初次暴露组（以10 ng/ml IL-10刺激6小时）；③ 静息组（以10 ng/ml IL-10刺激6小时后洗涤，再以0.5 ng/ml IL-10培养48小时，每12小时更换培养基）；④ 再次暴露组（操作同静息组，额外以10 ng/ml IL-10刺激6小时）