Abstract LB250: Multiplex screening of PBMCs with DNA barcoded peptide exchanged MHC trimers to identify peptide-specific paired VDJ TCRs at single cell level

Abstract

Abstract Elucidation of the paired TCR receptor-antigen synapse is important both for vaccine development and for targeted therapy. Linkage of T cell responses with specific antigenic peptides will not only guide the development of immunotherapies but also enable treatment response monitoring. Currently, single cell sequencing technology is well established, but the identification of specific pathogenic peptides and associated TCR in single cell level is still challenging. In most cases, ascertaining T cell responses to pathogenic peptides is based on the screening of pooled peptides that do not give the knowledge of corresponding responsive TCR to a particular peptide. We therefore developed a technique that uses DNA barcoded peptide exchanged MHC trimers to stain PBMCs. With this technique, multiple peptide-loaded trimers can be used to stain a PBMC sample in one test tube. Single cells positive for trimers are sorted, amplified, and sequenced together with the DNA barcode. Specific peptides can be identified with the DNA barcodes which are co-amplified with TCRs. Applying this technique, we screened one PBMC sample with several peptide-loaded trimers in one reaction. Utilizing the CDR3 identity of known clones against each of these peptides, we were able to demonstrate and validate that a multi-peptide screen using DNA barcodes is feasible. Further optimization is in progress to reduce background and to increase the multiplexing of barcoded peptide-trimers. Citation Format: Marc Delcommenne, Xiaohong Hou, Yuri Poluektov, Wenjing Pan, Emily Sims, Miranda Byrne-Steele. Multiplex screening of PBMCs with DNA barcoded peptide exchanged MHC trimers to identify peptide-specific paired VDJ TCRs at single cell level [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr LB250.