Department Pathology and Molecular Medicine, McMaster Immunology Research Centre, McMaster University, Hamilton, ON Canada.
J Immunother Cancer. 2015 Dec 15;3:55. doi: 10.1186/s40425-015-0099-4. eCollection 2015.
Adoptive cell transfer of tumor-specific T lymphocytes (T cells) is proving to be an effective strategy for treating established tumors in cancer patients. One method of generating these cells is accomplished through engineering bulk T cell populations to express chimeric antigen receptors (CARs), which are specific for tumor antigens. Traditionally, these CARs are targeted against tumor antigens using single-chain antibodies (scFv). Here we describe the use of a designed ankyrin repeat protein (DARPin) as the tumor-antigen targeting domain.
We prepared second generation anti-HER2 CARs that were targeted to the tumor antigen by either a DARPin or scFv. The CARs were engineered into human and murine T cells. We then compared the ability of CARs to trigger cytokine production, degranulation and cytotoxicity.
The DARPin CARs displayed reduced surface expression relative to scFv CARs in murine cells but both CARs were expressed equally well on human T cells, suggesting that there may be a processing issue with the murine variants. In both the murine and human systems, the DARPin CARs were found to be highly functional, triggering cytokine and cytotoxic responses that were similar to those triggered by the scFv CARs.
These findings demonstrate the utility of DARPins as CAR-targeting agents and open up an avenue for the generation of CARs with novel antigen binding attributes.
过继性细胞转移肿瘤特异性 T 淋巴细胞（T 细胞）被证明是治疗癌症患者已建立肿瘤的有效策略。生成这些细胞的一种方法是通过工程 bulk T 细胞群体来表达嵌合抗原受体（CARs），这些受体针对肿瘤抗原。传统上，这些 CAR 是使用单链抗体（scFv）针对肿瘤抗原靶向的。在这里，我们描述了使用设计的锚蛋白重复蛋白（DARPin）作为肿瘤抗原靶向结构域。
我们制备了第二代抗 HER2 CARs，这些 CAR 通过 DARPin 或 scFv 靶向肿瘤抗原。将 CAR 工程化到人类和鼠 T 细胞中。然后，我们比较了 CAR 触发细胞因子产生、脱颗粒和细胞毒性的能力。
与 scFv CAR 相比，DARPin CAR 在鼠细胞中的表面表达水平降低，但在人 T 细胞中表达水平相同，这表明鼠变体可能存在加工问题。在鼠和人系统中，DARPin CAR 被发现具有高度功能性，触发细胞因子和细胞毒性反应，与 scFv CAR 触发的反应相似。
这些发现证明了 DARPins 作为 CAR 靶向剂的实用性，并为生成具有新型抗原结合特性的 CAR 开辟了一条途径。
