IMMU-14. MENINGEAL PLASMA CELLS MOUNT AN IMMUNOLOGICAL DEFENSE AGAINST GLIOBLASTOMA

Abstract INTRODUCTION: Glioblastoma (GBM) represents the deadliest primary intracranial neoplasm. While many studies have focused on T cell responses to GBM, few examined role of humoral immunity. Here, we sought mechanistic insights into anatomy and function response against GBM. METHODS: C57BL/6J mice were injected stereotactically with syngeneic SB28 tumor cells. Humoral immunity was evaluated in spleen blood by high parameter flow cytometry meninges, brain, confocal microscopy. The importance interrogated using CD4-/- IgA-/- via transcranial application plasma survival factor, APRIL. RESULTS: High revealed a significant increase B cells (CD19+, CD138+) GBM within two weeks. Using blimp-1 reporter mice, observed that IgA+ localized extrafollicular splenic regions along meningeal dural venous sinuses near newly generated lymphatic vessels connected directly tumor. Decreased but not cells, suggesting helper independent IgA plays controlling This enhanced therapeutically CONCLUSION: Our results demonstrate elicits systemic response, which limiting growth can be transcranially participation offers new possibilities for therapeutic intervention this deadly disease.