Glioblastoma Immunotherapy Adjuvants for Glial Cell Polarization Regulation

Glioblastoma (GBM) remains fatal despite maximal surgical resection, temozolomide chemotherapy, and radiotherapy. Within the GBM microenvironment, tumor-educated microglia and astrocytes adopt immunoregulatory-like STAT3-high and ARG1/TGF-β-high phenotypes, respectively, which shield GBM cells from adaptive immune attack. In this review, we examine emerging adjuvant strategies designed to molecularly reprogram glial cells toward pro-inflammatory C3-high and IFN/NF-κB-high states, amplifying antitumor immunity. First, we summarize key aspects of GBM pathobiology and identify why conventional treatments fail to achieve durable control. Next, we dissect the signaling networks that govern glial phase states, including NF-κB, STAT3, IRF3, NLRP3, and cGAS-STING axes. We then provide a mechanism-centric analysis of pattern-recognition receptor (PRR) agonists, inflammasome modulators, and cyclic-dinucleotide STING agonists, integrating quantitative preclinical data with early clinical trial results. For each adjuvant, we distinguish between direct astrocytic engagement and indirect cytokine-mediated reprogramming. Modulation of glial phase states holds considerable promise for enhancing personalized vaccine efficacy and for converting immunologically "cold" GBM into a T cell-inflamed tumor. Consequently, targeting glial cell phase modulation is a highly attractive strategy for GBM immunotherapy, with the potential to maximize therapeutic benefit. Despite advances in chemo-, radio-, and checkpoint-blockade therapies, the immunosuppressive tumor microenvironment (TME) of GBM and its failure to establish memory immunity limit their impact. Tumor-polarized astrocytes and microglia form a barrier to effective T cell-mediated attack. Emerging evidence shows that redirecting glia toward pro-inflammatory phenotypes can recondition the TME, creating a more permissive landscape for immunotherapy. This review highlights glial phase reprogramming as a promising immunoadjuvant approach, emphasizing molecular circuits, synthetic modulators, and translational prospects.