Abstract 1364: Spatially resolved T-cell receptor profiling elucidates relationships between TCR diversity, immune infiltration, and cancer-associated pathways

Abstract As T-cells mature, genes encoding T-cell receptor (TCR) segments are somatically recombined to generate a diverse repertoire of receptors specific to unique antigens. The resultant TCR diversity, and subsequent clonal expansion events, are critical in understanding the adaptive immune response to pathogens and cancers. While many methods have been developed to determine specific clonotypes and overall TCR diversity present in various tissues, these methods to date have failed to capture spatial orientation and arrangement of T-cells engaging with their microenvironment. Tracking T-cell migration and infiltration into the tumor has thus been limited to post-hoc low-plex profiling methods. To better understand T-cell localization during tumor development, we have developed a TCR profiling panel for the GeoMx® Digital Spatial Profiler that can be combined with the GeoMx Cancer Transcriptome Atlas (CTA) or Human Whole Transcriptome Atlas (WTA). This novel spatial assay enables simultaneous quantification of all functional TCR constant, variable and joining segments in situ along with transcriptome-wide gene expression profiling in spatially defined regions of a tissue. We validated the performance of the TCR probe pool in inflamed tonsil and cell pellet arrays, demonstrating comparable sensitivity and specificity relative to orthogonal methods. We next used the GeoMx TCR spike-in panel to characterize intra- and inter-patient TCR heterogeneity in a cohort of 68 T-cell lymphomas to track clonal interactions between the malignant and non-malignant immune microenvironment. We demonstrate the ability to link the spatial context of TCR segment expression to activation of malignant signaling cascades as well as non-cancerous T-cell response to the presence of other immune cells and cancer-associated signaling. Together, the combination of our TCR spike-in panel with the CTA or WTA illuminates spatial distribution of T-cell clones paving the way for studies to comprehensively link TCR clonality changes to the tumor microenvironment. FOR RESEARCH USE ONLY. Not for use in diagnostic procedures. Citation Format: Michelle A. Kriner, Katrina van Raay, Jason W. Reeves, Kit A. Fuhrman, Andrew Klock, Alecksandr Kutchma, Erin Piazza, Joseph Beechem. Spatially resolved T-cell receptor profiling elucidates relationships between TCR diversity, immune infiltration, and cancer-associated pathways [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1364.