Inclusion of an IgG1-Fc spacer abrogates efficacy of CD19 CAR T cells in a xenograft mouse model
Inclusion of an IgG1-Fc spacer abrogates efficacy of CD19 CAR T cells in a xenograft mouse model
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DOI：
10.1038/gt.2015.4
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发表时间：
2015-05-01
期刊：
影响因子：
5.1
通讯作者：
Kyte, J. A.
中科院分区：
文献类型：
--
作者：
Almasbak, H.;Walseng, E.;Kyte, J. A.
用表达嵌合抗原受体（汽车）的T细胞进行癌症治疗在最近的试验中产生了显著的临床反应，但也产生了严重的副作用。尽管大多数方案使用永久重编程的T细胞，但我们已经开发了通过mRNA电穿孔进行瞬时CAR表达的平台。这种方法可能有助于新受体的安全临床试验，或需要临时治疗期时。在此，我们研究了在体外和异种移植小鼠模型中使用瞬时重定向T细胞的治疗。我们构建了一系列具有不同间隔区和共刺激结构域（CD 28、OX 40或CD 28-OX 40）的CD 19特异性汽车。CAR构建体均在体外赋予T细胞有效的CD 19特异性活性。出乎意料的是，掺入常用的IgG 1-C（H）2C（H）3间隔区的构建体显示缺乏体内抗白血病活性，并诱导严重的、部分不依赖于CD 19的毒性。相比之下，没有CH 2结构域的相同CAR构建体在体内根除了白血病，没有显著的毒性。后续研究表明，C（H）2C（H）3-间隔区结合可溶性小鼠Fc。受体I和介导的针对鼠巨噬细胞的脱靶T细胞活化。我们的研究结果强调了非信号CAR元件和体内研究的重要性。最后，结果表明，瞬时重定向的T细胞控制小鼠白血病，并支持开发mRNA-CAR平台的基本原理。
Cancer therapy with T cells expressing chimeric antigen receptors (CARs) has produced remarkable clinical responses in recent trials, but also severe side effects. Whereas most protocols use permanently reprogrammed T cells, we have developed a platform for transient CAR expression by mRNA electroporation. This approach may be useful for safe clinical testing of novel receptors, or when a temporary treatment period is desirable. Herein, we investigated therapy with transiently redirected T cells in vitro and in a xenograft mouse model. We constructed a series of CD19-specific CARs with different spacers and co-stimulatory domains (CD28, OX40 or CD28-OX40). The CAR constructs all conferred T cells with potent CD19-specific activity in vitro. Unexpectedly, the constructs incorporating a commonly used IgG1-C(H)2C(H)3 spacer showed lack of anti-leukemia activity in vivo and induced severe, partly CD19-independent toxicity. By contrast, identical CAR constructs without the CH2-domain eradicated leukemia in vivo, without notable toxicity. Follow-up studies demonstrated that the C(H)2C(H)3-spacer bound soluble mouse Fc.-receptor I and mediated off-target T-cell activation towards murine macrophages. Our findings highlight the importance of non-signalling CAR elements and of in vivo studies. Finally, the results show that transiently redirected T cells control leukemia in mice and support the rationale for developing an mRNA-CAR platform.