Toxoplasma gondii infection supports the infiltration of T cells into brain tumors

Primary brain tumors, residing behind the blood-brain-barrier (BBB), have few infiltrated T cells. We hypothesized that Toxoplasma gondii, a microorganism that naturally traffics to the brain to elicit a Th1 response, can promote T cell infiltration into brain tumors. Using a mouse genetic model for medulloblastoma, we found that T. gondii infection was well-controlled in tumor-bearing mice, induced robust infiltration of T cells into the tumor, and led to myeloid cell transcriptional reprogramming toward a T cell-supportive state. The study demonstrates that the immune modulatory capacity of T. gondii could be leveraged to promote brain tumor immunotherapy through future efforts.