PO.TB10.16 · 肿瘤生物学
与突变型IL-2连接的逻辑门控T细胞衔接器用于更安全更有效的实体瘤免疫治疗
Logic-gated T cell engager linked with mutant IL-2 for safer and better effective solid tumor immunotherapy
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摘要 Abstract
中文摘要
T细胞衔接器(TCEs)在B细胞恶性肿瘤中取得了变革性成功,但在实体瘤中疗效有限且毒性严重。在此,我们确定IL-2信号不足是维持TCE诱导的T细胞功能的关键瓶颈。尽管外源性IL-2增强TCE疗效,但其全身给药会导致更严重的毒性。为克服这一局限,我们设计了一种蛋白酶可激活的双可变结构域(DVD)作为Pro-TCE以降低其脱靶毒性。此外,我们设计了一种受体亲和力显著降低、在外周无活性的突变型IL-2(3E)。该构建体(DVD-3E)在循环中保持惰性,仅在肿瘤特异性蛋白酶切割后于局部被激活,将T细胞衔接与顺式(cis)IL-2信号相偶联。这种逻辑门控设计将TCE和细胞因子活性限制在肿瘤微环境(TME)内,实现强效抗肿瘤应答而无全身毒性。机制上,DVD-3E增强了预先存在的肿瘤内T细胞的持久性和效应功能,扩增了TCF1⁺祖细胞和抗原特异性T细胞群,减轻了耗竭,并建立了持久的免疫记忆。值得注意的是,DVD-3E治疗增加了引流淋巴结中抗原特异性T细胞的频率,这些细胞在过继转移后能够控制远处肿瘤并介导有效的肿瘤消退。这些发现为逻辑门控TCEs定义了一种新的设计原则,在安全性和疗效之间实现了有利的平衡,为克服当前治疗耐药提供了一种策略。
查看英文原文 English abstract
T cell engagers (TCEs) have achieved transformative success in B-cell malignancies but show limited efficacy in solid tumors with severe toxicity. Here, we identify insufficient IL-2 signaling as a key bottleneck for sustaining TCE-induced T-cell function. Although exogenous IL-2 enhances TCE efficacy, its systemic administration causes more severe toxicity. To overcome this limitation, we engineered a protease-activatable dual-variable-domain (DVD) as Pro-TCE to reduce its off-tumor toxicity. Furthermore, we designed a mutant IL-2 (3E) with markedly reduced receptor affinity that is inactive in periphery. The construct (DVD-3E) remains inert in circulation and becomes locally activated only upon tumor-specific protease cleavage, coupling T-cell engagement with cis IL-2 signaling. This logic-gated design restricts both TCE and cytokine activity to the tumor microenvironment (TME), enabling potent antitumor responses without systemic toxicity. Mechanistically, DVD-3E enhances the persistence and effector function of preexisting intratumoral T cells, expands TCF1⁺ progenitor and antigen-specific T cells populations, mitigates exhaustion, and establishes durable immune memory. Notably, DVD-3E treatment increased the frequency of antigen-specific T cells in draining lymph nodes, which were capable of controlling distant tumors and mediating effective tumor regression upon adoptive transfer. These findings define a new design principle for logic gated TCEs that achieve a favorable balance between safety and efficacy, offering a strategy to overcome current therapeutic resistant.
利益披露 Disclosure
Y. Fu, None.