PO.IM01.15 · 免疫学
干扰素-alpha和PD-1阻断以肿瘤激活的方式相互掩蔽
Interferon-alpha and PD-1 blockade mutually mask each other in a tumor-activated manner
作者与单位 Authors & Affiliations
摘要 Abstract
中文摘要
（目的）免疫检查点阻断（ICB）疗法彻底改变了癌症治疗，但常因肿瘤通过丧失MHC I抗原呈递而发生免疫逃逸受到限制。I型干扰素发挥强效抗肿瘤作用，可能将无应答者转变为应答者；然而，其全身给药因严重的免疫相关不良事件（irAEs）而受限。为在不损害安全性的前提下提高疗效，我们开发了一种肿瘤激活的IFNalpha-PD-1，利用双重掩蔽使两个组分在全身范围内保持无活性。
（方法）该阻断技术通过将IFNalpha整合到抗PD-1抗体的框架中来减弱分子生物活性。通过这种双重掩蔽设计，细胞因子和抗体功能均受到空间位阻约束，防止在循环中过早激活。当肿瘤选择性接头发生蛋白水解切割后即发生重新激活，这一过程被称为空间重扣（spatial reclasp），可恢复分子柔性并释放IFNalpha与抗体之间的相互空间位阻。这种构象去掩蔽能够仅在肿瘤微环境内同时恢复细胞因子信号传导和检查点阻断。
（结果）在ELISA试验中，失活的锁定分子相对于亲本抗体表现出抗原结合活性降低>20倍，而蛋白酶激活可将结合恢复至与亲本形式相当的水平。激活的融合分子诱导黑色素瘤细胞中MHC I表达显著上调，证实了空间受限的IFNalpha信号传导。在体内，IFNalpha-PD1融合分子表现出卓越的肿瘤抑制作用和增强的瘤内T细胞浸润，且全身毒性极小。
（结论）本研究确立了IFNalpha作为一种肿瘤激活的检查点锁定分子，在恢复抗肿瘤免疫的同时减轻全身毒性。这种双重掩蔽架构为工程化条件性激活的免疫肿瘤学治疗提供了可推广的框架，支持未来在各种ICB模式中的即插即用应用，并实现更安全、更强效的下一代癌症免疫疗法。
查看英文原文 English abstract
(Purpose) Immune checkpoint blockade (ICB) therapies have revolutionized cancer treatment but are often constrained by tumor immune evasion through the loss of MHC I antigen presentation. Type I interferons exert potent antitumor effects that may convert non-responders into responders; however, their systemic administration is limited by severe immune-related adverse events (irAEs). To improve efficacy without compromising safety, we developed a tumor-activated IFNalpha-PD-1 that uses dual masking to keep both elements inactive systemically.
(Methods) The blocking technology attenuates molecular bioactivity by integrating IFNalpha into the frameworks of anti-PD-1 antibodies. Through this dual-masking design, both cytokine and antibody functions are sterically constrained, preventing premature activation in circulation. Reactivation occurs upon proteolytic cleavage of a tumor-selective linker, a process termed spatial reclasp, which restores molecular flexibility and releases mutual steric hindrance between IFNalpha and the antibody. This conformational unmasking enables simultaneous recovery of cytokine signaling and checkpoint blockade exclusively within the tumor microenvironment.
(Results) In ELISA assays, the inactivated lockers exhibited more than 20-fold reductions in antigen-binding activity relative to the parental antibodies, whereas protease activation restored binding to levels comparable with the parental forms. The activated fusion induced marked upregulation of MHC I expression in melanoma cells, confirming spatially restricted IFNalpha signaling. In vivo, the IFNalpha-PD1 fusion demonstrated superior tumor suppression and enhanced intratumoral T cell infiltration with minimal systemic toxicity.
(Conclusions) This work establishes IFNalpha as a tumor-activated checkpoint locker that restores antitumor immunity while mitigating systemic toxicity. The dual-masking architecture provides a generalizable framework for engineering conditionally active immuno-oncology therapeutics, supporting future plug-and-play applications across ICB modalities and enabling safer, more potent next-generation cancer immunotherapies.
利益披露 Disclosure
S. Chao, None..
C. Chuang, None.