Generation of a novel fusion protein to redirect macrophage differentiation following radiation therapy.

 描述(申请人提供)：放射治疗是一种高效的杀灭癌细胞的方法，我们和其他人已经证明，放射后释放的抗原佐剂可以产生和增强适应性免疫反应，特别是在与免疫调节治疗一起使用时。然而，这些作用受到辐射肿瘤中的肿瘤相关巨噬细胞的限制，这些巨噬细胞通过与直接反对抗肿瘤免疫反应的辐射细胞相互作用来指导组织修复。我们建议使用一种新的表型来靶向指导辐射后巨噬细胞这种修复表型的特定途径。我们假设巨噬细胞对辐射的免疫反应可以从修复表型重定向到适应性促进免疫反应，使用一种新的Gas6-CD40L融合蛋白。在这项研究中，我们建议对这种新的融合蛋白进行初步鉴定。为了做到这一点，我们建议解决以下具体目标。目的：研究Gas6-CD40L融合蛋白与死亡细胞的体外结合及其激活巨噬细胞的能力。目的：确定Gas6-CD40L融合蛋白在无肿瘤和带瘤小鼠体内的药代动力学和毒性分布。目的：检测Gas6-CD40L融合蛋白对荷瘤小鼠局部照射后肿瘤相关巨噬细胞的作用。我们的研究设计包括融合蛋白结合的体外特征和对巨噬细胞极化的影响，以及体内药代动力学、毒性和生物分布的研究。该项目的成功完成将为进一步开展更广泛的研究提供必要的初步数据和可行性。

 DESCRIPTION (provided by applicant): Radiation therapy is a highly effective modality to kill cancer cells, and we and others have demonstrated that both antigen adjuvant release following radiation can generate and enhance adaptive immune responses particularly when used with immunomodulatory therapies. However these effects are limited by tumor associated macrophages in the radiated tumor that direct tissue repair in response to interaction with irradiated cells that directly oppose anti-tumor immune responses. We propose targeting a specific pathway that directs this repair phenotype in macrophages following radiation using a novel phenotype. We hypothesize that the macrophage immune response to radiation can be redirected away from a repair phenotype and toward an adaptive promoting immune response using a novel Gas6-CD40L fusion protein. We propose in this study to perform initial characterization of this novel fusion protein. To do this we propose addressing the following specific aims. Aim1: Characterize the in vitro binding of a Gas6-CD40L fusion protein to dying cells and its ability to activate macrophages. Aim2: Define both the in vivo pharmacokinetic and toxicity profile of a Gas6-CD40L fusion protein in both tumor free and tumor bearing mice. Aim3: Test the in vivo function of a Gas6-CD40L fusion protein on tumor associated macrophages following focal radiation in tumor bearing mice. Our study design incorporates in vitro characterization of fusion protein binding and effect on macrophage polarization as well as in vivo studies of pharmacokinetics, toxicity and biodistribution. The successful completion of this project will provide the necessary preliminary data and feasibility for further development in more extensive studies.