With our work, we try to address the mechanisms that might explain how the interaction of glioblastoma cells with pericytes allows tumor to grow and infiltrate brain parenchyma; and to specifically determine the relevance of this intercellular interaction in the modulation of the anti-glioblastoma immune response. A non-immunosuppressed mouse Glioblastoma model has been defined as a useful tool to study human Glioblastoma . The use of xenografts of human glioblastoma cells makes our experimental model more relevant to demonstrate an immunoregulatory mechanism activated by human glioblastoma. We show that, even under those conditions, immunocompetent C57BL/6 wild type mice cannot reject human glioblastoma tumor, likely due to the potent ability of glioblastoma cells to induce immune tolerance. Our purpose was to use this system to identify those mechanisms that allow glioblastoma cells to induce such a profound tolerant state, and may also represent a new approach to develop new experimental designs to study GBM-immune system interactions.