深入验证人类和小鼠 CD4 特异性迷你抗体，用于 CD4 细胞的非侵入性 PET 成像和癌症免疫治疗反应预测。

In-depth cross-validation of human and mouse CD4-specific minibodies for noninvasive PET imaging of CD4 cells and response prediction to cancer immunotherapy.

机构信息

Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, University Hospital Tuebingen, University of Tuebingen, Tuebingen, Germany.

Department of Nuclear Medicine, University Hospital Tuebingen, Eberhard Karls University, Tuebingen, Germany.

出版信息

Theranostics. 2024 Aug 1;14(12):4582-4597. doi: 10.7150/thno.95173. eCollection 2024.

DOI:10.7150/thno.95173

PMID:39239511

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC11373626/

Abstract

Increasing evidence emphasizes the pivotal role of CD4 T cells in orchestrating cancer immunity. Noninvasive imaging of the temporal dynamics of CD4 T cells and their distribution patterns might provide novel insights into their effector and regulator cell functions during cancer immunotherapy (CIT). We conducted a comparative analysis of Zr-labeled anti-mouse (m) and anti-human (h) CD4-targeting minibodies (Mbs) for positron emission tomography (PET)/magnetic resonance imaging (MRI) of CD4 T cells in human xenografts, syngeneic tumor-bearing wild-type (WT), and human CD4 knock-in (hCD4-KI) mouse models. Both Zr-CD4-Mbs yielded high radiolabeling efficiencies of >90%, immunoreactivities of >70%, and specific binding to their target antigens. The specificity of targeting of Zr-hCD4-Mb was confirmed by PET/MRI, revealing ~4-fold greater Zr-hCD4-Mb uptake in subcutaneous hCD4 hematopoietic peripheral blood acute lymphoblastic leukemia tumors (HPB-ALL) than in solid hCD4 diffuse histiocytic lymphomas (DHL) and Zr-mCD4-Mb uptake in hCD4 HPB-ALL tumors. In a comparative cross-validation study in anti-programmed death ligand (αPD-L1)/anti-4-1BB-treated orthotopic PyMT mammary carcinoma-bearing hCD4-KI and WT mice, we detected 2- to 3-fold enhanced species-specific Zr-hCD4-Mb or Zr-mCD4-Mb uptake within CD4 cell-enriched secondary lymphatic organs (lymph nodes and spleens). The Zr-hCD4-Mb uptake in the PyMT tumors was more pronounced in hCD4-KI mice compared to the WT control littermates. Most importantly, MC38 adenocarcinoma-bearing mice treated with a combination of αPD-L1 and anti-lymphocyte-activation gene 3 (αLag-3) antibodies exhibited ~1.4-fold higher Zr-mCD4-Mb uptake than mice that were not responsive to therapy or sham-treated mice. CD4 PET/MRI enabled monitoring of the CD4 cell distribution in secondary lymphatic organs and the tumor microenvironment, capable of predicting sensitivity to CIT. Our imaging approach will provide deeper insights into the underlying molecular mechanisms of CD4-directed cancer immunotherapies in preclinical mouse models and is applicable for clinical translation.

摘要

越来越多的证据强调了 CD4 T 细胞在协调癌症免疫中的关键作用。非侵入性地对 CD4 T 细胞的时间动态及其分布模式进行成像，可能为它们在癌症免疫治疗（CIT）期间的效应和调节细胞功能提供新的见解。我们对 Zr 标记的抗小鼠（m）和抗人（h）CD4 靶向 minibodies（Mbs）进行了比较分析，用于人异种移植物、同基因肿瘤荷瘤野生型（WT）和人 CD4 敲入（hCD4-KI）小鼠模型中 CD4 T 细胞的正电子发射断层扫描（PET）/磁共振成像（MRI）。Zr-CD4-Mbs 的放射性标记效率均>90%，免疫反应性均>70%，且均特异性结合其靶抗原。Zr-hCD4-Mb 靶向的特异性通过 PET/MRI 得到证实，在皮下 hCD4 造血外周血急性淋巴细胞白血病肿瘤（HPB-ALL）中，Zr-hCD4-Mb 的摄取比在实体 hCD4 弥漫性组织细胞性淋巴瘤（DHL）和 Zr-mCD4-Mb 中的摄取高约 4 倍。在抗程序性死亡配体（αPD-L1）/抗 4-1BB 治疗的原位 PyMT 乳腺肿瘤荷瘤 hCD4-KI 和 WT 小鼠的交叉验证研究中，我们检测到在富含 CD4 细胞的次级淋巴器官（淋巴结和脾脏）中，种特异性 Zr-hCD4-Mb 或 Zr-mCD4-Mb 的摄取增强了 2-3 倍。与 WT 对照同窝仔相比，hCD4-KI 小鼠的 PyMT 肿瘤中 Zr-hCD4-Mb 的摄取更为明显。最重要的是，用 αPD-L1 和抗淋巴细胞激活基因 3（αLag-3）抗体联合治疗的 MC38 腺癌荷瘤小鼠的 Zr-mCD4-Mb 摄取比未对治疗有反应或假处理的小鼠高约 1.4 倍。CD4 PET/MRI 能够监测次级淋巴器官和肿瘤微环境中 CD4 细胞的分布，能够预测对 CIT 的敏感性。我们的成像方法将为临床前小鼠模型中 CD4 定向癌症免疫治疗的潜在分子机制提供更深入的了解，并适用于临床转化。