mRNA-LNP vaccination induces microenvironment remodeling and generation of tissue-resident memory T cells in glioblastoma

Glioblastoma remains highly refractory to immunotherapy, in part because of a profoundly immunosuppressive tumour microenvironment that limits effective T-cell responses. Although mRNA vaccines can induce anti-tumour immunity, how they reshape the glioblastoma immune ecosystem to support durable tumour control is not well understood. Here we use an immunocompetent EGFRvIII-driven syngeneic glioblastoma model and antigen-specific mRNA lipid nanoparticle (mRNA-LNP) vaccination to define the cellular and spatial mechanisms underlying therapeutic response. In our model, vaccination induced durable EGFRvIII-specific humoral and cellular immunity, resulting in complete tumour eradication and long-term protection against intracranial rechallenge. Integrative analyses incorporating flow cytometry, tumour interstitial fluid profiling, multiplex immunostaining, spatial transcriptomics and ligand-receptor modelling demonstrated extensive remodelling of the tumour microenvironment following vaccination. Early tumour control was associated with expansion of pro-inflammatory and antigen-presenting myeloid populations, increased cytotoxic CD8 T-cell infiltration and activation, enhanced interferon-responsive signalling, and the formation of immune-supportive spatial niches enriched for antigen presentation and chemokine-mediated cellular communication. Vaccination promoted inflammatory chemokine relay networks centred on the CXCL16-CXCR6 axis, a pathway linked to tissue residency programming in the central nervous system. Functional depletion studies identified CD4 and CD8 T cells as essential mediators of therapeutic efficacy, while durable protection was maintained by tumour-specific brain-resident memory CD8 T cells that persisted despite peripheral lymphocyte depletion. Together, these findings identify T-cell-driven microenvironmental remodelling as a critical mechanism linking mRNA vaccination to the establishment of long-term brain-resident anti-tumour immunity in glioblastoma.