A Chimeric Antigen Receptor That Binds to a Conserved Site on MICA.
A Chimeric Antigen Receptor That Binds to a Conserved Site on MICA.
复制标题
DOI：
10.4049/immunohorizons.2000041
复制
发表时间：
2020-10-09
期刊：
影响因子：
--
通讯作者：
Sentman, Charles L
中科院分区：
文献类型：
--
作者：
Cook, W James;Choi, Yoonjoo;Sentman, Charles L
NKG2D配体MHC-I类链相关蛋白A(MICA)在多种肿瘤细胞中表达，但在大多数正常组织中不表达，因此是嵌合抗原受体(CAR)T细胞治疗的潜在靶点。然而，MICA有100多个等位基因，所以靶向保守位置的能力是大多数患者使用的治疗方法。在这项研究中，我们描述了通过将单链片段变量B2融合到全长DAP10蛋白和传统的CD3zeta信号域而创建的全人抗MICA CAR。在小鼠异种移植模型中，表达B2CAR的人T细胞杀死MICA阳性肿瘤细胞，当与MICA阳性肿瘤细胞或平板结合的MICA蛋白接触时产生干扰素-γ，并抑制Panc-1的生长。为了将B2的S表位定位在云母细胞上，我们使用了新的计算方法来模拟潜在的结合模式，并设计了云母细胞的突变变体来验证这些假说。用商品化的抗MICA/MICB单抗进行流式细胞术分析表明，在转导的P815细胞系中高水平表达了这些不同的蛋白。与对照组相比，一种变异蛋白(R38S/K40T/K57E)与B2-IgG1融合蛋白的染色减少，并且不能诱导表达B2 CAR的人T细胞产生干扰素-γ。这些结果显示了MICA特异性CAR T细胞的抗肿瘤活性，并表明在涉及MICA的aA38-57的暴露环中的保守位置起着重要作用。这项研究描述了一种新型的MICA特异性CAR，并讨论了它作为癌症治疗的潜在用途。
The NKG2D ligand MHC class I chain-related protein A (MICA) is expressed on many varieties of malignant cells but is absent from most normal tissues, and thus represents a potential target for chimeric Ag receptor (CAR) T cell-based therapeutics. However, there are more than 100 alleles of MICA, so the ability to target a conserved site is needed for a therapy to be used in most patients. In this study, we describe a fully human anti-MICA CAR created by fusing the single-chain fragment variable B2 to the full length DAP10 protein and the traditional CD3zeta signaling domain. Human T cells expressing the B2 CAR killed MICA-positive tumor cells, produced IFN-gamma when in contact with MICA-positive tumor cells or plate-bound MICA protein, and inhibited PANC-1 growth in a mouse xenograft model. To localize B2's epitope on MICA, we used novel computational methods to model potential binding modes and to design mutational variants of MICA testing these hypotheses. Flow cytometry using a commercial anti-MICA/MICB Ab indicated that the variant proteins were expressed at high levels on transduced P815 cell lines. One variant protein (R38S/K40T/K57E) showed reduced staining with a B2-IgG1 fusion protein compared with controls and did not induce IFN-gamma production by human T cells expressing the B2 CAR. These results show antitumor activity of MICA-specific CAR T cells and indicate an essential role for a conserved site in the exposed loop involving aa 38-57 of MICA. This study describes a novel MICA-specific CAR and discusses its potential use as a cancer therapeutic.