靶向NKG2D 配体的CAR-T细胞在小鼠模型中的致死毒性研究

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T Cells Engineered With Chimeric Antigen Receptors Targeting NKG2D Ligands Display Lethal Toxicity in Mice.

Abstract

Ligands for the NKG2D receptor are over expressed on tumors, making them interesting immunotherapy targets. To assess the tumoricidal properties of T cells directed to attack NKG2D ligands, we engineered murine T cells with two distinct NKG2D-based chimeric antigen receptors (CARs): (i) a fusion between the NKG2D receptor and the CD3ζ chain and (ii) a conventional second-generation CAR, where the extracellular domain of NKG2D was fused to CD28 and CD3ζ. To enhance the CAR surface expression, we also engineered T cells to coexpress DAP10. In vitro functionality and surface expression levels of all three CARs was greater in BALB/c T cells than C57BL/6 T cells, indicating strain-specific differences. Upon adoptive transfer of NKG2D-CAR-T cells into syngeneic animals, we observed significant clinical toxicity resulting in morbidity and mortality. The severity of these toxicities varied between the CAR configurations and paralleled their in vitro NKG2D surface expression. BALB/c mice were more sensitive to these toxicities than C57BL/6 mice, consistent with the higher in vitro functionality of BALB/c T cells. Treatment with cyclophosphamide prior to adoptive transfer exacerbated the toxicity. We conclude that while NKG2D ligands may be useful targets for immunotherapy, the pursuit of NKG2D-based CAR-T cell therapies should be undertaken with caution.

靶向NKG2D 配体的CAR-T细胞在小鼠模型中的致死毒性研究

摘要：

NKG2D受体的配体在肿瘤细胞表面高度表达，使得其成为了一种非常有趣的免疫治疗靶点。为了评估T细胞直接攻击NKG2D配体带来的肿瘤杀伤毒性，我们设计了两种不同的以NKG2D为基础的小鼠来源的CAR-T细胞：（1）NKG2D受体与CD3ζ链的融合。（2）一个传统二代CAR-T细胞，细胞外的NKG2D区域链接CD28和CD3ζ。为了增强CAR在细胞表面的表达，我们也改造T细胞，使其表达DAP10。在BALB/c T细胞中，这三种CAR在细胞表面的表达和体外的功能比C57BL/6 T细胞更优秀，包括种属特异性差异。对于NKG2D CAR-T细胞移植到同种动物模型中，我们观察到明显的临床毒副作用，导致了发病率和死亡率。这些毒性的不同与CAR的结构以及NKG2D的表面表达有关联。BALB/c小鼠对这些毒性的敏感程度高于C57BL/6小鼠，同时BALB/c T 细胞在体外有更好的功能。过继T细胞移植之前使用环磷酰胺会增加毒性。我们得出以下的结论，尽管NKG2D配体可能对免疫靶向治疗有很大的帮助，但是以NKG2D CAR-T细胞为基础的治疗技术仍然需要谨慎对待。

出自爱康得生物技术