CD11b Antibody Fragments as PET Imaging Probes for Glioma-Associated Myeloid Cells

摘要 胶质母细胞瘤患者的平均生存时间保持在15个月左右，因为相对较少的有效治疗。 治疗。CD 11b+肿瘤相关髓样细胞可占肿瘤质量的40%， 已知其抑制抗肿瘤免疫并直接促进肿瘤生长。虽然取得了重大进展， 尽管在TAMC靶向治疗的开发中已经进行了大量的研究，但TAMC的分析需要分析手术治疗的结果。 切除的肿瘤组织。在这个R21应用中，我们建议开发一种新的示踪剂，Cu-64标记 抗体片段，这将允许胶质母细胞瘤中TAMC的非侵入性PET成像。因此， 验证我们的新假设，即Cu-64标记的单抗体或双抗体来源于m1/70杂交瘤 将能够定量TAMC浸润到肿瘤中并监测TAMC靶向的 免疫疗法我们将首先生成并测试注射后抗体片段的灵敏度 将来自C57 BL/6 j小鼠的不同浓度的CD 11b+小鼠脾细胞转化为CD 11b敲除的C57 BL/6 j- 背景同基因胶质瘤荷瘤小鼠（Aim 1）。然后我们将证明我们的新型抗体片段 可用于监测TAMC靶向治疗，包括抗Gr 1抗体、塞来昔布或CSF-1 R抑制剂 在GL 261同源神经胶质瘤模型和新生神经胶质瘤模型（AIM 2）中。正如m1/70克隆体可以识别的那样 无论是人类还是小鼠CD 11b，我们相信我们的临床前研究可以快速转化我们的发现， 在胶质母细胞瘤患者或其他神经炎性疾病患者中进行TAMC靶向临床试验 紊乱 !

ABSTRACT Average survival times for glioblastoma patients remain around 15 months because of relatively few effective treatments. CD11b+ Tumor-associated myeloid cells, can account for up to 40% of the tumor mass, are well known to suppress anti-tumor immunity, and directly promote tumor growth. While significant advances have been made in the development of TAMC-targeted therapies, analysis of TAMCs requires analysis of surgically resected tumor tissue. In this R21 application we propose that development of a novel tracer, Cu-64 labeled antibody fragments, which will allow for non-invasive PET imaging of TAMCs in glioblastomas. We will therefore, test our novel hypothesis that Cu-64-labeled monobodies or diabodies derived from the m1/70 hybridoma will enable quantification TAMC infiltration into the tumor and monitoring of TAMC-targeted immunotherapies. We will first generate and test the sensitivity of our antibody fragments following injections of varying concentrations of CD11b+ mouse spleenocytes from C57BL/6j mice into CD11b-knockout C57BL/6j- background syngeneic glioma-bearing mice (Aim 1). We will then demonstrate that our novel antibody fragments can be used to monitor TAMC-targeted therapies including anti-Gr1-antibody, Celecoxib, or a CSF-1R inhibitor in the GL261 syngeneic glioma model, and a de novo glioma model (AIM 2). As the m1/70 clone can recognize both human and mouse CD11b, we believe that our preclinical studies can lead to quick translation of our findings into TAMC-targeted clinical trials in patients with glioblastoma, or in patients with other neuroinflammatory disorders. !