Childhood brain tumors instruct cranial hematopoiesis and immunotolerance.

Abstract

Recent research has challenged a long-held view of the brain as an immune-privileged organ, revealing active immunosurveillance with therapeutic relevance. Using a new genetically engineered mouse model of ZFTA-RELA ependymoma, a childhood brain tumor, we characterized an immune circuit between the tumor and antigen-presenting hematopoietic stem and progenitor cells (HSPCs) in the skull bone marrow. The presentation of antigens by HSPCs to CD4T cells biased HSPC lineages toward myelopoiesis and polarized CD4T cells to regulatory T cells, culminating in tumor immunotolerance. Remarkably, normalizing hematopoiesis with a single infusion of antibodies directed against cytokines enriched in the cerebrospinal fluid of mice bearing ZFTA-RELA ependymomas, choroid plexus carcinomas or group 3 medulloblastoma-all aggressive childhood brain tumors-disrupted this process and caused profound tumor regression. These findings demonstrate the existence of a skull bone marrow-tumor immunological interface and suggest that modulating the local supply of myeloid cells could represent a less toxic therapeutic strategy for aggressive childhood brain tumors.