Innovative Immunotherapies Unit, Division of Immunology, Transplantation and Infectious Diseases, IRCCS San Raffaele Scientific Institute, Milan, Italy.
Experimental Hematology Unit, Division of Immunology, Transplantation and Infectious Diseases, IRCCS San Raffaele Scientific Institute, Milan, Italy.
Front Immunol. 2020 Jun 19;11:1217. doi: 10.3389/fimmu.2020.01217. eCollection 2020.
Chimeric antigen receptor (CAR) T cell expansion and persistence emerged as key efficacy determinants in cancer patients. These features are typical of early-memory T cells, which can be enriched with specific manufacturing procedures, providing signal one and signal two in the proper steric conformation and in the presence of homeostatic cytokines. In this project, we exploited our expertise with paramagnetic beads and IL-7/IL-15 to develop an optimized protocol for CAR T cell production based on reagents, including a polymeric nanomatrix, which are compatible with automated manufacturing the CliniMACS Prodigy. We found that both procedures generate similar CAR T cell products, highly enriched of stem cell memory T cells (T) and equally effective in counteracting tumor growth in xenograft mouse models. Most importantly, the optimized protocol was able to expand CAR T from B-cell acute lymphoblastic leukemia (B-ALL) patients, which in origin were highly enriched of late-memory and exhausted T cells. Notably, CAR T cells derived from B-ALL patients proved to be as efficient as healthy donor-derived CAR T cells in mediating profound and prolonged anti-tumor responses in xenograft mouse models. On the contrary, the protocol failed to expand fully functional CAR T from patients with pancreatic ductal adenocarcinoma, suggesting that patient-specific factors may profoundly affect intrinsic T cell quality. Finally, by retrospective analysis of data, we observed that the proportion of T in the final CAR T cell product positively correlated with expansion, which in turn proved to be crucial for achieving long-term remissions. Collectively, our data indicate that next-generation manufacturing protocols can overcome initial T cell defects, resulting in T-enriched CAR T cell products qualitatively equivalent to the ones generated from healthy donors. However, this positive effect may be decreased in specific conditions, for which the development of further improved protocols and novel strategies might be highly beneficial.
嵌合抗原受体 (CAR) T 细胞的扩增和持久性是癌症患者疗效的关键决定因素。这些特征是早期记忆 T 细胞的典型特征，这些细胞可以通过特定的制造工艺进行富集，从而在适当的空间构象中提供信号一和信号二，并存在稳态细胞因子。在这个项目中，我们利用我们在超顺磁性珠和 IL-7/IL-15 方面的专业知识，开发了一种基于试剂的优化 CAR T 细胞生产方案，包括一种聚合物纳米基质，这些试剂与自动化制造兼容 ClinMACS Prodigy。我们发现，这两种方法都能产生类似的 CAR T 细胞产品，高度富集干细胞记忆 T 细胞 (T)，并且在异种移植小鼠模型中同样有效地抑制肿瘤生长。最重要的是，优化方案能够从 B 细胞急性淋巴细胞白血病 (B-ALL) 患者中扩增 CAR T，这些患者最初高度富集晚期记忆 T 细胞和耗竭 T 细胞。值得注意的是，源自 B-ALL 患者的 CAR T 细胞在介导异种移植小鼠模型中的深刻和持久的抗肿瘤反应方面与健康供体衍生的 CAR T 细胞一样有效。相反，该方案未能从胰腺导管腺癌患者中完全扩增功能性 CAR T，表明患者特异性因素可能会深刻影响内在 T 细胞质量。最后，通过对数据的回顾性分析，我们观察到最终 CAR T 细胞产品中 T 的比例与扩增呈正相关，而扩增又被证明是实现长期缓解的关键。总的来说，我们的数据表明，下一代制造方案可以克服初始 T 细胞缺陷，产生质量上等同于从健康供体中产生的 T 细胞富集的 CAR T 细胞产品。然而，在特定条件下，这种积极的效果可能会降低，对于这些情况，开发进一步改进的方案和新策略可能会非常有益。
