PO.IM02.04 · 免疫学

High-throughput discovery of MART1-specific TCR-peptide interactions using a Jurkat NFAT Reporter-K562 antigen-presenting cell system and single-cell adaptive immune receptor profiling

海报缩略图:High-throughput discovery of MART1-specific TCR-peptide interactions using a Jurkat NFAT Reporter-K562 antigen-presenting cell system and single-cell adaptive immune receptor profiling
编号 4249 展板 17 🕑 4/21 09:00–12:00 📍 Section 6 主讲 Alex Chenchik, PhD
分会场 Adaptive Immunity in Cancer
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作者与单位 Authors & Affiliations

Alex Chenchik1, Debbie Deng1, Kitt Paraiso1, Guido Stadler2, Ben Yellen2

1Cellecta, Inc., Mountain View, CA,2Celldom, San Carlos, CA

摘要 Abstract

In this study, we developed a high-throughput workflow for identifying MART1-specific T cell receptor (TCR)-peptide interactions relevant to melanoma immunotherapy. Jurkat NFAT-GFP reporter cells expressing individual candidate MART1-TCRs (n=10 to 20) were co-cultured with K562 artificial antigen-presenting cells (APCs) engineered to express a MART1 120-peptide, tumor-associated library in a single-chain trimer (peptide-B2M-HLA-A) format. TCR activation was quantified using the CellDom Microwell EliSpot platform, where GFP expression and IL-2 secretion signaled productive antigen engagement. Cells from positive wells were harvested, and DriverMap adaptive immune receptor (AIR) bulk and single-cell TCR-Seq assays and subsequent NGS analysis were performed to identify the cognate TCR epitopes.To improve epitope presentation, we introduced a G2C substitution in the G4S linker of the single-chain trimer, which enhanced HLA surface expression and increased Jurkat activation compared with the wild-type construct. MART1-TCRs showed differential reactivity across the MART peptide panel, enabling ranking of functional affinity and identification of cross-reactive peptide candidates. Both the bulk AIR DNA and bulk AIR RNA assays show clonotypes that are expanded in MART1 vs Day 0 (control) or DMSO control. On Day 9, approximately 12 clonotypes are expanded at 250x compared to Day 0 in the MART1-stimulated sample. With the single-cell AIR assay, the MART1-stimulated samples showed overrepresentation of clones, whereas there was no clonal overrepresentation in the DMSO control plate.This end-to-end platform shows TCR-peptide interactions with bulk and & single-cell NGS readout, which could enable identification of therapeutic TCR candidates, and provide a scalable method for characterizing antigen specificity for cancer immunotherapy applications.
利益披露 Disclosure
A. Chenchik, Cellecta Employment. D. Deng, Cellecta Employment. K. Paraiso, Cellecta Employment. G. Stadler, Celldom Employment. B. Yellen, Celldom Employment.

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