IMMU-29. PERIPHERAL VACCINATION WITH GIFT-7 SECRETING TUMOR CELLS AUGMENTS AGE RELATED THYMIC DECLINE AND IMPROVES SURVIVAL ACROSS MULTIPLE GLIOBLASTOMA MOUSE MODELS

Abstract Glioblastoma (GBM), the most common primary brain tumor in adults, has a dismal prognosis and nearly 100% recurrence rate. With median age of diagnosis 64, associated immune dysfunction needs to be accounted for during treatment. Cannonically, immunotherapies target checkpoint signaling pathways order create T-cell populations that are resistant exhaustion. Our lab demonstrated exhaustion is not only factor at play regarding dysfunction, as patients with GBM have robust CD8+CD28- effector population present both blood tumor, possibly indicating senescence. Here we research utilizing GIFT-7, fusiokine combining GMCSF IL-7, which been combat related thymic decline. To accurately understand this phenomenon context aging all experiments were done mice aged 52 weeks before intial injection. We transfected mouse glioma line GL261 cells stably express secrete GIFT-7 injected 500k (GIFT7/VC) subcutaneously flank B6 mice. This allowed continued systemic administration GIFT7, well exposure similar vaccine model. After 4 an intracranial challenge normal was conducted survival monitored. Mice flanks had larger CD3 CD4 T-cells their circulation (p < .001 p .05 respectively). also observed increased tendency (CD3, CD4+, CD8+) within brain. Finally, vastly improved 60% showing long term ( > 120 days) compared 0 VC