Ex Vivo Expansion of Melanoma Tumor-Infiltrating Lymphocytes Leads to a Dominant Exhausted T-Cell Population with a Lack of Memory Markers

Scientists performed single-cell RNA and T cell receptor sequencing of tumor-infiltrating lymphocytes (TILs) isolated from patient tumors and their paired ex vivo expanded cell products. They found large transcriptional differences between pre- and post-expansion TILs.