Department of Health Technology, Technical University of Denmark, Lyngby, Denmark.
PokeAcell Aps, BioInnovation Institute, Copenhagen, Denmark.
J Immunother Cancer. 2023 Aug;11(8). doi: 10.1136/jitc-2023-006847.
Adoptive cell therapy (ACT) has shown promising results for the treatment of cancer and viral infections. Successful ACT relies on ex vivo expansion of large numbers of desired T-cells with strong cytotoxic capacity and in vivo persistence, which constitutes the greatest challenge to current ACT strategies. Here, in this study, we present a novel technology for ex vivo expansion of antigen-specific T-cells; artificial antigen-presenting scaffolds (Ag-scaffolds) consisting of a dextran-polysaccharide backbone, decorated with combinations of peptide-Major Histocompatibility Complex (pMHC), cytokines and co-stimulatory molecules, enabling coordinated stimulation of antigen-specific T-cells.
The capacity of Ag-scaffolds to expand antigen-specific T-cells was explored in ex vivo cultures with peripheral blood mononuclear cells from healthy donors and patients with metastatic melanoma. The resulting T-cell products were assessed for phenotypic and functional characteristics.
We identified an optimal Ag-scaffold for expansion of T-cells for ACT, carrying pMHC and interleukin-2 (IL-2) and IL-21, with which we efficiently expanded both virus-specific and tumor-specific CD8+ T cells from peripheral blood of healthy donors and patients, respectively. The resulting T-cell products were characterized by a high frequency of antigen-specific cells with high self-renewal capacity, low exhaustion, a multifunctional cytokine profile upon antigen-challenge and superior tumor killing capacity. This demonstrates that the coordinated stimuli provided by an optimized stoichiometry of TCR engaging (pMHC) and stimulatory (cytokine) moieties is essential to obtain desired T-cell characteristics. To generate an 'off-the-shelf' multitargeting Ag-scaffold product of relevance to patients with metastatic melanoma, we identified the 30 most frequently recognized shared HLA-A0201-restricted melanoma epitopes in a cohort of 87 patients. By combining these in an Ag-scaffold product, we were able to expand tumor-specific T-cells from 60-70% of patients with melanoma, yielding a multitargeted T-cell product with up to 25% specific and phenotypically and functionally improved T cells.
Taken together, the Ag-scaffold represents a promising new technology for selective expansion of antigen-specific CD8+ T cells directly from blood, yielding a highly specific and functionally enhanced T-cell product for ACT.
过继细胞疗法（ACT）在癌症和病毒感染的治疗中显示出了很好的效果。成功的 ACT 依赖于大量具有强大细胞毒性和体内持久性的所需 T 细胞的体外扩增，这是当前 ACT 策略所面临的最大挑战。在这里，本研究提出了一种新的体外扩增抗原特异性 T 细胞的技术；由葡聚糖-多糖骨架组成的人工抗原呈递支架（Ag-支架），其上缀合了肽-主要组织相容性复合物（pMHC）、细胞因子和共刺激分子的组合，从而能够协调地刺激抗原特异性 T 细胞。
我们用健康供者和转移性黑色素瘤患者的外周血单个核细胞在体外培养中探索了 Ag-支架扩增抗原特异性 T 细胞的能力。评估了所得 T 细胞产物的表型和功能特征。
我们确定了一种用于 ACT 的最优 Ag-支架，其携带 pMHC 和白细胞介素-2（IL-2）和 IL-21，我们用其分别有效地从健康供者和患者的外周血中扩增了病毒特异性和肿瘤特异性 CD8+T 细胞。所得 T 细胞产物的特征是抗原特异性细胞具有高自我更新能力、低衰竭、抗原刺激后具有多功能细胞因子谱以及优异的肿瘤杀伤能力。这表明，通过 TCR 结合（pMHC）和刺激（细胞因子）部分的优化化学计量提供协调刺激对于获得所需的 T 细胞特征是至关重要的。为了生成与转移性黑色素瘤患者相关的“现成”多靶向 Ag-支架产品，我们在 87 名患者的队列中鉴定了 30 个最常被识别的 HLA-A0201 限制性黑色素瘤表位。通过将这些表位结合到 Ag-支架产品中，我们能够从 60-70%的黑色素瘤患者中扩增肿瘤特异性 T 细胞，从而产生具有多达 25%特异性和表型及功能改善的 T 细胞的多靶向 T 细胞产物。
总的来说，Ag-支架代表了一种有前途的新技术，可直接从血液中选择性扩增抗原特异性 CD8+T 细胞，产生用于 ACT 的高度特异性和功能增强的 T 细胞产物。
