Fig. 7: Utilization of trogocytosis.

a Mouse thymoma EL4 cells were labeled with membrane markers, such as 3,3′-dioctadecyl-oxacarbocyanine perchlorate (DiO), and co-cultured with CD8 T cells. As a result, DiO was transferred to CD8 T cells in an antigen-specific manner through trogocytosis. The isolation of DiO+ cells enabled the characterization of antigen-specific CD8 T cells. b Using single-chain trimer technology, a library of tumor-associated antigens (TAAs) was generated and transduced into K562 leukemia cells. Biotin-labeled Jurkat cells were then co-cultured with K562 cells expressing TAAs. Trogocytosis involves the transfer of biotin to target K562 cells. Isolation of biotin+ cells enriched with K562 cells expressing TAAs with high TCR specificity. The selected TAAs were identified via next-generation sequencing (NGS). c Patient-derived T cells expressing exhaustion markers, such as PD-1 or TIM-3, showed enhanced cytotoxicity against target cells, indicating high antigen specificity. After these PD-1+ TIM-3+ T cells were co-cultured with U266 cells, trogocytosis transferred CD3 from the T cells to the U266 cells. Isolation of CD3+ U266 cells after co-culture, followed by TCR identification, can reveal TAA-specific TCRs via the PeptiChip technique.