Purcarea Anna, Jarosch Sebastian, Barton Jack, Grassmann Simon, Pachmayr Ludwig, D'Ippolito Elvira, Hammel Monika, Hochholzer Anna, Wagner Karolin I, van den Berg Joost H, Buchholz Veit R, Haanen John B A G, Busch Dirk H, Schober Kilian
Institute for Medical Microbiology, Immunology, and Hygiene, Technische Universität München (TUM), Munich, Germany.
BioTherapeutics Unit, Netherlands Cancer Institute, Amsterdam, Netherlands.
Sci Immunol. 2022 Aug 12;7(74):eabm2077. doi: 10.1126/sciimmunol.abm2077.
T cell receptor (TCR) avidity is assumed to be a major determinant of the spatiotemporal fate and protective capacity of tumor-specific T cells. However, monitoring polyclonal T cell responses with known TCR avidities in vivo over space and time remains challenging. Here, we investigated the fate and functionality of tumor neoantigen-specific T cells with TCRs of distinct avidities in a well-established, reductionist preclinical tumor model and human patients with melanoma. To this end, we used polyclonal T cell transfers with in-depth characterized TCRs together with flow cytometric phenotyping in mice inoculated with MC38 OVA tumors. Transfer of T cells from retrogenic mice harboring TCRs with high avidity resulted in best tumor protection. Unexpectedly, we found that both high- and low-avidity T cells are similarly abundant within the tumor and adopt concordant phenotypic signs of exhaustion. Outside the tumor, high-avidity TCR T cells were not generally overrepresented but, instead, selectively enriched in T cell populations with intermediate PD-1 protein expression. Single-cell sequencing of neoantigen-specific T cells from two patients with melanoma-combined with transgenic reexpression of identified TCRs by CRISPR-Cas9-mediated orthotopic TCR replacement-revealed high-functionality TCRs to be enriched in T cells with RNA signatures of recent activation. Furthermore, of 130 surface protein candidates, PD-1 surface expression was most consistently enriched in functional TCRs. Together, our findings show that tumor-reactive TCRs with high protective capacity circulating in peripheral blood are characterized by a signature of recent activation.
T细胞受体（TCR）亲和力被认为是肿瘤特异性T细胞时空命运和保护能力的主要决定因素。然而，在体内随时间和空间监测具有已知TCR亲和力的多克隆T细胞反应仍然具有挑战性。在这里，我们在一个成熟的、简化的临床前肿瘤模型和黑色素瘤患者中，研究了具有不同亲和力TCR的肿瘤新抗原特异性T细胞的命运和功能。为此，我们在接种MC38 OVA肿瘤的小鼠中，使用了具有深入特征的TCR的多克隆T细胞转移以及流式细胞术表型分析。转移来自携带高亲和力TCR的逆转录基因小鼠的T细胞，可产生最佳的肿瘤保护作用。出乎意料的是，我们发现高亲和力和低亲和力T细胞在肿瘤内同样丰富，并呈现出一致的耗竭表型特征。在肿瘤外，高亲和力TCR T细胞通常并不占优势，而是选择性地富集在具有中等PD-1蛋白表达的T细胞群体中。对两名黑色素瘤患者的新抗原特异性T细胞进行单细胞测序，并通过CRISPR-Cas9介导的原位TCR替换对鉴定出的TCR进行转基因重新表达，结果显示高功能性TCR富集在具有近期激活RNA特征的T细胞中。此外，在130种表面蛋白候选物中，PD-1表面表达在功能性TCR中最一致地富集。总之，我们的研究结果表明，在外周血中循环的具有高保护能力的肿瘤反应性TCR具有近期激活的特征。
