The Glioma-Infiltrating T Cell Receptor Repertoire

While immune signaling has emerged as a defining feature of the glioma microenvironment, local selection of responding T cells and their anti-tumor potential as a population are difficult to measure directly in patients. High-throughput sequencing of T cell receptor repertoires (TCRseq) provides a population-wide statistical description of how T cells respond to disease. Here, we define new immunophenotypes in glioma based on TCRseq and RNA-Seq of tumor tissue, non-neoplastic brain tissue, and peripheral blood from patients. Using information theory, we characterize antigen-driven selection in glioma and its relationship with the expression of distinct immune-functional pathways in the tumor microenvironment. Finally, we identify a strong relationship between usage of certain TCR in peripheral blood and the divergence of the infiltrating T cell population from the peripheral repertoire. We anticipate that these immunophenotypes will be foundational to monitoring and predicting response to anti-glioma vaccines and immunotherapy. Overall design: We characterized the T cell receptor (TCR) repertoires of 11 high-grade glioma patients, three low-grade glioma patients, and thee non-glioma patients by TCRseq of brain-infiltrating T cells and matching peripheral blood. In addition, we obtained gene expression profiles from brain tissue of each patient by RNA-Seq. We additionally measured the TCR repertoires exclusively from peripheral blood of one additional non-glioma patient.