A New Approach to Modulating CAR T Cell Activity

摘要 靶向CD 19的嵌合抗原受体（CAR）T细胞在患有 难治性/复发性急性淋巴细胞白血病（ALL），包括原发性 难治性或CNS疾病。目前的CAR T细胞疗法为患者注入T细胞 组成型表达汽车，其不受任何可控调节的影响。 细胞因子释放综合征（CRS）和CAR相关的神经毒性（CAN），两者均 可能是致命的，由不受控制的CAR T细胞激活和扩增引起。而少数 已经尝试了药物管理方法来克服这个问题， 往往是次优的。此外，来自持续性CD 19 CAR T细胞的慢性B细胞再生障碍性贫血 需要每月输注免疫球蛋白，这是负担和昂贵的，特别是 对于可能面临终生需求的儿科患者。在这里，我们建议开发一个系统， 可以根据需要打开和关闭的可控CAR T细胞。我们先前已经 表明外源表达的酪氨酸磷酸酶SHP-1作为一种抑制剂， 抑制T细胞活化的负调节因子。最近，我们开发了一种诱导型的， 植物生长素诱导的SHP-1可逆蛋白降解系统 (AID)T细胞系统。在目标1中结合这两个工具，我们建议开发CD 19 CAR T细胞将通过SHP-1的过表达保持基本休眠。然而，在这方面， 在施用生长素后，CAR T细胞可以暂时且可逆地活化， 通过降解SHP-1。因为生长素的剂量足以激活AID系统 在人类中没有明显的毒性，我们不认为翻译这个系统会有问题。 进了诊所在目标2中，我们将检查这种新型CAR T细胞系统在小鼠中的功效。 所有的模型。在目标3中，我们将扩大研究，以测试这种可调节的CAR T细胞是否 系统可以使用ALL模型控制和/或限制CAR T细胞相关毒性， CRS和神经毒性。这种外源可调节的CAR T细胞系统可以提供 临床医生的工具，以避免/限制严重的CRS和CAN，并允许重新增殖的B细胞 经过充分的治疗后，这种方法将大大提高安全性 CD 19 CAR T细胞，可能适用于其他恶性肿瘤的汽车，包括实体瘤。 肿瘤，其中靶向、组织外细胞毒性更成问题。

Abstract Chimeric antigen receptor (CAR) T cells targeting CD19 are highly effective in children with refractory/relapsed acute lymphoblastic leukemia (ALL), including those with primary refractory or CNS disease. Current CAR T cell therapies infuse patients with T cells constitutively expressing CARs, which are not susceptible to any controllable regulation. Cytokine release syndrome (CRS) and CAR-associated neurotoxicity (CAN), both of which can be fatal, arise from uncontrolled CAR T cell activation and expansion. While a few pharmacological management approaches have been attempted to overcome this issue, they are often suboptimal. In addition, chronic B-cell aplasia from persistent CD19 CAR T cells requires monthly infusions of immunoglobulin, which is burdensome and expensive, especially for pediatric patients facing potentially a lifetime need. Here, we propose to develop a system for controllable CAR T cells that can be turned on and off as needed. We have previously demonstrated that exogenous expression of the tyrosine phosphatase SHP-1 acts as a negative regulator to dampen T cell activation. Recently, we have developed an inducible and reversible protein degradation system for SHP-1 by adapting the plant Auxin-induced degron (AID) system for T cells. Combining these two tools in Aim 1, we propose to develop CD19 CAR T cells that will be kept basally dormant through overexpression of SHP-1. However, upon administration of Auxin, the CAR T cells can be temporarily and reversibly activated through the degradation of SHP-1. As the doses of Auxin sufficient to activate the AID system had no significant toxicities in humans, we do not foresee a problem translating this system into the clinic. In Aim 2, we will examine the efficacy of this novel CAR T cell system in a murine model of ALL. In Aim 3, we will expand the studies to test whether this regulatable CAR T cells system can control and/or limit CAR T cell-associated toxicities using a muring model of ALL, CRS and neurotoxicity. Such an exogenously regulatable CAR T cell system may provide clinicians a tool to avoid/limit severe CRS and CAN, and allow repopulation of the B-cell compartment after a sufficient treatment course. This approach will greatly enhance the safety of CD19 CAR T cells and is likely applicable to CARs for other malignancies, including solid tumors, where on-target, off-tissue cytotoxicity is more problematic.