Tumor infiltration by myeloid suppressor cells in response to T cell activation in rat gliomas.

We have recently reported that activation of tumor-specific T cells by subcutaneous vaccination with irradiated T9 glioma cells of syngeneic rats with a pre-existing, intracranial (i.c.) T9 glioma (T9+vaccination) promotes the mobilization of myeloid suppressor cells (MSC) which inhibit T cell function resulting in unregulated tumor progression.