针对三阴性乳腺癌（TNBC）的免疫检查点阻断疗法（ICT）靶向程序性细胞死亡蛋白-1/配体-1（PD-1/PD-L1）已经提高了患者的持久反应。不幸的是，仅有19-23%的患者从ICT中受益。因此，评估疗效和选择从ICT中受益的患者的非侵入性策略对于TNBC免疫疗法是关键问题。我们开发了一种新型纳米粒子-Atezolizumab（NPs-Ate），由吲哚菁绿（ICG）、聚乙烯二胺五乙酸钆（Gd-DTPA）、人血清白蛋白（HSA）和Atezolizumab组成。采用质谱法验证了Gd-DTPA连接的效率，并利用纳米流式细胞仪表征了NPs-Ate的大小。评估了合成的NPs-Ate的荧光稳定性、穿透深度和靶向特异性。使用TNBC细胞系和带瘤小鼠模型评估了这种双模式第二近红外/磁共振成像（NIR-II/MRI）系统的可行性。此外，将ICT与化疗或放疗组合用于TNBC带瘤小鼠模型，评估PD-L1的动态变化以及利用NPs-Ate预测治疗反应。成功地将Atezolizumab标记为ICG和Gd-DTPA生成NPs-Ate。在我们的NIR-II成像系统中，表现出强烈的荧光信号，其松弛度（γ1）为9.77 mM-1 s-1。在带瘤小鼠中，NIR-II成像信号的背景比率（SBR）在注射探针后36小时达到了11.51的峰值，而MRI成像SBR则在注射探针后12小时达到了1.95的峰值。NPs-Ate特异性地靶向表达PD-L1的细胞和肿瘤，能够在免疫疗法期间监测PD-L1的状态。综合疗法导致抑制肿瘤生长，延长存活时间，增加PD-L1表达，通过非侵入性的NPs-Ate成像系统有效监测。NIR-II/MRI NPs-Ate有效反映了免疫疗法期间的PD-L1状态。在TNBC中，在NIR-II/MRI成像指导下的实时和非侵入性免疫疗法和反应/预后监测是一项有前景、创新的技术，有着广泛的临床应用前景。© 2023 刘等

Durable responses to immune-checkpoint blocking therapy (ICT) targeting programmed cell death protein-1/ligand-1 (PD-1/PD-L1) have improved outcomes for patients with triple negative breast cancer (TNBC). Unfortunately, only 19-23% of patients benefit from ICT. Hence, non-invasive strategies evaluating responses to therapy and selecting patients who will benefit from ICT are critical issues for TNBC immunotherapy.We developed a novel nanoparticle-Atezolizumab (NPs-Ate) consisting of indocyanine green (ICG), gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA), human serum albumin (HSA), and Atezolizumab. The efficiency of Gd-DTPA linking was verified using mass spectrometry, and the size of NPs-Ate was characterized using Nano-flow cytometry. The synthesized NPs-Ate were evaluated for fluorescence stability, penetration depth, and target specificity. TNBC cell lines and tumor-bearing mice models were used to identify the feasibility of this dual-modal second near-infrared/magnetic resonance imaging (NIR-II/MRI) system. Additionally, ICT combination with chemotherapy or radiotherapy in TNBC tumor-bearing mice models were used to assess dynamic changes of PD-L1 and predicted therapeutic responses with NPs-Ate.Atezolizumab, a monoclonal antibody, was successfully labeled with ICG and Gd-DTPA to generate NPs-Ate. This demonstrated strong fluorescence signals in our NIR-II imaging system, and relaxivity (γ1) of 9.77 mM-1 s-1. In tumor-bearing mice, the NIR-II imaging signal background ratio (SBR) reached its peak of 11.51 at 36 hours, while the MRI imaging SBR reached its highest as 1.95 after 12 hours of tracer injection. NPs-Ate specifically targets cells and tumors expressing PD-L1, enabling monitoring of PD-L1 status during immunotherapy. Combining therapies led to inhibited tumor growth, prolonged survival, and increased PD-L1 expression, effectively monitored using the non-invasive NPs-Ate imaging system.The NIR-II/MRI NPs-Ate effectively reflected PD-L1 status during immunotherapy. Real-time and non-invasive immunotherapy and response/prognosis monitoring under NIR-II/MRI imaging guidance in TNBC is a promising and innovative technology with potential for extensive clinical applications in the future.© 2023 Liu et al.