程序化细胞死亡蛋白1（PD-1）信号通路是肿瘤微环境中抑制T细胞活性的主要来源。虽然通过抗体阻断来抑制PD-1通路的临床方法取得了广泛的成功，但这些方法导致广泛的PD-1抑制，增加了自身免疫反应的风险。本研究报道了一种可离子化脂质纳米颗粒（LNP）平台的开发，用于同时在T细胞中进行治疗性mRNA表达和RNA干扰（RNAi）介导的瞬时基因敲除。在开发这一平台过程中，观察到两种RNA荷载体共同包装时的有趣相互作用，导致与单独传递任一荷载体相比，表达和敲除特性得到了改善。该信使RNA（mRNA）/小干扰RNA（siRNA）共同传递平台被用于体外向原代人T细胞传递嵌合抗原受体（CAR）mRNA和靶向PD-1的siRNA，观察到了强烈的CAR表达和PD-1敲除，而整体T细胞活化状态似乎没有明显改变。这种传递平台对于瞬时免疫基因调控在多个免疫工程应用中显示出巨大潜力，包括在改进癌症免疫治疗中的应用。本文受版权保护。保留所有权利。

The programmed cell death protein 1 (PD-1) signaling pathway is a major source of dampened T cell activity in the tumor microenvironment (TME). While clinical approaches to inhibiting the PD-1 pathway using antibody blockade have been broadly successful, these approaches lead to widespread PD-1 suppression, increasing the risk of autoimmune reactions. This work reports the development of an ionizable lipid nanoparticle (LNP) platform for simultaneous therapeutic mRNA expression and RNA interference (RNAi)-mediated transient gene knockdown in T cells. In developing this platform, interesting interactions were  observed between the two RNA cargoes when co-encapsulated, leading to improved expression and knockdown characteristics compared to delivering either cargo alone. This messenger RNA (mRNA)/small interfering RNA (siRNA) co-delivery platform was  adopted to deliver chimeric antigen receptor (CAR) mRNA and siRNA targeting PD-1 to primary human T cells ex vivo and strong CAR expression and PD-1 knockdown were  observed without apparent changes to overall T cell activation state. This delivery platform shows great promise for transient immune gene modulation for a number of immunoengineering applications, including in the development of improved cancer immunotherapies. This article is protected by copyright. All rights reserved.This article is protected by copyright. All rights reserved.