Immunotherapy efficacy as monotherapy is negligible for glioblastoma (GBM). We hypothesized that combining therapeutic vaccination using a plasmid encoding an epitope derived from GBM-associated antigen (pTOP) with local delivery of immunogenic chemotherapy using mitoxantrone-loaded PEGylated PLGA-based nanoparticles (NP-MTX) would improve the survival of GBM-bearing mice by stimulating an antitumor immune response. We first proved that MTX retained its ability to induce cytotoxicity and immunogenic cell death of GBM cells after encapsulation. Intratumoral delivery of MTX or NP-MTX increased the frequency of IFN-γ-secreting CD8 T cells. NP-MTX mixed with free MTX in combination with pTOP DNA vaccine increased the median survival of GL261-bearing mice and increased M1-like macrophages in the brain. The addition of CpG to this combination abolished the survival benefit but led to increased M1 to M2 macrophage ratio and IFN-γ-secreting CD4 T cell frequency. These results highlight the benefits of combination strategies to potentiate immunotherapy and improve GBM outcome.

对于胶质母细胞瘤 (GBM)，免疫疗法作为单一疗法的疗效可以忽略不计。我们假设将使用编码源自 GBM 相关抗原 (pTOP) 的表位的质粒进行治疗性疫苗接种与使用载有米托蒽醌的聚乙二醇化 PLGA 纳米颗粒 (NP-MTX) 进行免疫原性化学疗法的局部递送相结合，将提高携带 GBM 的小鼠的存活率通过刺激抗肿瘤免疫反应。我们首先证明 MTX 在封装后保留了诱导 GBM 细胞的细胞毒性和免疫原性细胞死亡的能力。MTX 或 NP-MTX 的瘤内递送增加了分泌 IFN-γ 的 CD8 T 细胞的频率。NP-MTX 与游离 MTX 混合并结合 pTOP DNA 疫苗可增加携带 GL261 的小鼠的中位存活率并增加大脑中的 M1 样巨噬细胞。向该组合中添加 CpG 消除了生存优势，但导致 M1 与 M2 巨噬细胞比率和分泌 IFN-γ 的 CD4 T 细胞频率增加。这些结果突出了联合策略在增强免疫治疗和改善 GBM 结果方面的优势。