Purpose

Due to the recent rise in immunotherapy research to treat glioblastoma (GBM), immunocompetent mouse models have become increasingly crucial. However, the character and kinetics of the immune response against the most prevalent immunocompetent GBM models, GL261 and CT2A, have not been well studied, nor has the impact of commonly-used marker proteins and foreign antigens.

Methods

In this study, we compared the immune response in these models using flow cytometry and immunohistochemistry as well as investigated several factors that influence the immune response, including kinetics, tumor size, and expression of commonly-used marker proteins and foreign antigens. We hypothesize that these factors influence the immune response enough to warrant consideration when studying new immunotherapeutic approaches for GBM.

Results

CT2A-Luc, but not GL261-Luc2, drastically increased the number of T cells in the brain compared with wild-type controls, and significantly altered CT2A’s responsiveness to anti-PD-1 antibody therapy. Additionally, a larger cell inoculum size in the GL261 model increased the T cell response’s magnitude at day 28 post-injection. CT2A and GL261 models both stimulate a peak T cell immune response at day 21 post-injection.

Conclusions

Our results suggest that the impact of foreign proteins like luciferase on the intracranial immune response is dependent upon the model, with CT2A being more sensitive to added markers. In particular, luciferase expression in CT2A could lead to meaningful misinterpretations of results from immune checkpoint inhibitor (ICI) studies.

中文翻译：

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技术选择以模型依赖的方式显着改变了针对免疫活性小鼠神经胶质瘤的适应性免疫反应

目的

由于最近治疗胶质母细胞瘤 (GBM) 的免疫疗法研究的兴起，免疫活性小鼠模型变得越来越重要。然而，针对最普遍的免疫活性 GBM 模型 GL261 和 CT2A 的免疫反应特征和动力学尚未得到充分研究，常用标记蛋白和外源抗原的影响也没有得到很好的研究。

方法

在这项研究中，我们使用流式细胞术和免疫组织化学比较了这些模型中的免疫反应，并研究了影响免疫反应的几个因素，包括动力学、肿瘤大小以及常用标记蛋白和外来抗原的表达。我们假设这些因素对免疫反应的影响足以在研究 GBM 的新免疫治疗方法时值得考虑。

结果

与野生型对照相比，CT2A-Luc（而非 GL261-Luc2）显着增加了大脑中 T 细胞的数量，并显着改变了 CT2A 对抗 PD-1 抗体治疗的反应。此外，GL261 模型中较大的细胞接种量增加了注射后第 28 天 T 细胞反应的幅度。CT2A 和 GL261 模型均在注射后第 21 天刺激 T 细胞免疫反应峰值。

结论

我们的研究结果表明，荧光素酶等外源蛋白对颅内免疫反应的影响取决于模型，CT2A 对添加的标记物更敏感。特别是，CT2A 中的荧光素酶表达可能导致对免疫检查点抑制剂 (ICI) 研究结果的有意义的误解。