CRISPR-Mediated Immunotherapy Efficacy in Glioblastoma Mouse Models

Glioblastoma multiforme (GBM) remains one of the most aggressive and lethal forms of primary brain cancer, with median survival under 15 months despite standard-of-care treatment. This study evaluates the efficacy of CRISPR-Cas9-mediated knockout of immune checkpoint genes as a complement to anti-PD-1 immunotherapy in syngeneic GL261 mouse models of GBM. We hypothesized that targeted disruption of PD-L1 expression on tumor cells would enhance T-cell infiltration and improve response to checkpoint blockade. Across three cohorts (n=24 mice per arm), the combined CRISPR + anti-PD-1 group showed a statistically significant 47% increase in median survival (p < 0.01) compared to anti-PD-1 alone, and a 2.3-fold increase in CD8+ tumor-infiltrating lymphocyte density on flow cytometry. These results support continued investigation of CRISPR-augmented immunotherapy strategies for GBM.