TMIC-29. CHARACTERIZING THE ROLE OF TRIGGERING RECEPTOR EXPRESSED ON MYELOID CELLS 2 (TREM2)-EXPRESSING MICROGLIA/MACROPHAGES IN GLIOBLASTOMA

Abstract The tumor microenvironment in glioblastoma (GBM) contains numerous cell types, notably a rich immune compartment dominated by myeloid cells, such as brain-resident microglia and infiltrating macrophages. However, current immunotherapies target lymphoid components like T which are sparse the brain tumors originating there. Therefore, checkpoint drugs designed for systemic cancers have not yielded significant benefits patients with glioblastoma, efficacy of immunotherapy central nervous system malignancies lags behind treatments other solid tumors. Further understanding is necessary developing immunotherapies. Our recent single RNA-seq (scRNA-seq) analyses identified microglial clusters that enriched antigen presentation phagocytic gene expression modules. These were restricted to macrophages seen only glioma patients, but cells derived from non-glioma controls. Triggering receptor expressed on 2 (TREM2), abundant vital detection phagocytosis pathogens, was highly these clusters. Because expressing TREM2 play protective role neurodegenerative diseases Alzheimer's disease, we examined function TREM2+ GBM using mice lacking TREM2. Implantation GL261 TREM2-/- showed significantly reduced survival relative wild-type mice, suggesting glioma. Data immunophenotyping xenografts WT brains state art technologies (e.g. Cytek) will be presented. We conclude immunoregulator manifesting anti-glioma properties cells.