Abstract LB094: First of its kind T cell receptors and functional proteomics detected from the same single cells to advance cancer immunology discovery
Authors: Yang Jennifer , Zhou Jing , Mackay Sean 
Published: June 2022

Abstract
T cell receptor repertoire diversity and T cell cytokine production are the important attributes for the assessment of effective T cell immunity against cancer and pathogens, yet existing single-cell genomics platforms cannot interrogate TCR sequences and proteomic cytokines simultaneously. IsoPlexis’ functional proteomics has demonstrated the values in cell therapy and cancer immunology against blood cancers and solid tumors. The ability to connect the T cell receptor diversity to the most potent single cells enables a wide variety of applications for tumor infiltrating lymphocytes, personalized neoantigen TCR’s, cancer immunology in terms of understanding antigen specificity, as well as self-potency. IsoPlexis single-cell TCR Duomic platform provide a unique measurement for connecting T cell receptor sequences to those T cell cytokine profiles, for the first time. Human PBMC-derived T cell line established from healthy donor was stimulated with PMA/ionomycin (2ul/ml, Biolegend) for 6hrs, stained and resuspended in Reverse transcription premix containing reverse transcriptase with buffer and protein phosphatase inhibitor at 1 x 106/ml and then loaded on Duomic chips. Ran on IsoLight overnight, cDNA was collected from the chip followed by cleanup and amplification, proceeded with TCR amplification and sequencing on NextSeq 1000/2000. Proteomic data from single cells was automatically generated and analyzed by IsoSpeak software. The single-cell TCR sequencing data on the IsoPlexis TCR Duomics platform shows that 78.9% cells have TCR alpha chain recombination and 94.4% cells have TCR beta chain recombination. Totally 77.7% cells have combination on both alpha and beta chain. VDJ Usage Plot further displays the top10 most common V (D) J combination flow between T cell receptor alpha chain and beta chain among the single cells, revealing the diversity of TCR repertoire at the single-cell level. In addition, the proteomics data identifies the dominant proteins among the single cells are Granzyme B, GM-CSF, IFN-g and TNF-a. Furthermore, we define 3 distinct cell clusters based on functional proteins and an association of VDJ distribution with these cell clusters, suggesting the occurrence of V(D)J sequences in the most common reconstructed alpha and beta sequence. IsoPlexis single-cell TCR Duomics platform, for the first time, enables simultaneous profiling of functional proteomics and TCR repertoires/TCR clonotypes as well as identification of specific TCR V(D)J combination with functional cell clusters across the same individual T cells. The combination of these two analytes at the single cells provides a key new modality of tracking the most potent and also the antigen specific immune cells together to fight cancer and infectious disease, for the first time.
Citation Format: Jennifer Yang, Jing Zhou, Sean Mackay. First of its kind T cell receptors and functional proteomics detected from the same single cells to advance cancer immunology discovery [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 LB094.