Department of Veterinary Clinical Sciences, The Ohio State University, Columbus, Ohio, USA.
Division of Rheumatology and Immunology, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.
J Orthop Res. 2021 Apr;39(4):821-830. doi: 10.1002/jor.24900. Epub 2020 Dec 15.
γ-Tilmanocept ( Tc-tilmanocept) is a receptor-directed, radiolabeled tracer that is FDA-approved for guiding sentinel lymph node biopsy. Tilmanocept binds the C-type lectin mannose receptor (MR, CD206) on macrophages. In this study, nonradioactive, fluorescently-labeled Cy3-tilmanocept was used to detect CD206 mononuclear cells in the cartilage of mice with antibody-induced arthritis and in the synovial fluid and tissue of human subjects with rheumatoid arthritis (RA) for comparison with osteoarthritis (OA), and healthy volunteer (HV) controls. Murine arthritis was induced by injection of monoclonal anti-cartilage antibody followed by injection of Escherichia coli lipopolysaccharide. Post-arthritis development (7-11 days), the mice were injected intravenously with Cy3-tilmanocept followed by in vivo and ex vivo epifluorescence imaging. Two-photon imaging, immunofluorescence, and immunohistochemistry were used to identify articular and synovial macrophages (CD206, F4/80, and Cy3-tilmanocept binding) in murine tissues. Cy3-tilmanocept epifluorescence was present in arthritic knees and elbows of murine tissues; no radiographic changes were noted in the skeletons. However, inflammatory arthritic changes were apparent by histopathology and immunohistochemistry (F4/80), immunofluorescence (CD206) and Cy3-tilmanocept binding. In human RA synovial fluid, Cy3-tilmanocept staining correlated with CD206 /CD16 cells; negligible labeling was observed in OA samples. Cy3-tilmanocept colocalized with CD206 and staining was significantly higher in RA synovial tissue compared to OA or HV. Our results demonstrate that imaging with Cy3-tilmanocept can detect in vivo inflammatory, CD206 macrophages in an early arthritis animal model and in human RA patients. These data establish a novel tool for preclinical research of early arthritis and have implications for early RA detection and monitoring of therapeutic efficacy in humans.
γ-甘露糖基化替拉诺肽（Tc-替拉诺肽）是一种受体靶向的放射性标记示踪剂，已获得美国食品药品监督管理局（FDA）批准，用于指导前哨淋巴结活检。替拉诺肽与巨噬细胞上的 C 型凝集素甘露糖受体（MR，CD206）结合。在这项研究中，使用非放射性荧光标记的 Cy3-替拉诺肽检测了诱导关节炎的小鼠软骨中的 CD206 单核细胞，以及人类类风湿关节炎（RA）患者的滑液和组织，以与骨关节炎（OA）和健康志愿者（HV）对照进行比较。通过注射单克隆抗软骨抗体然后注射大肠杆菌脂多糖诱导小鼠关节炎。关节炎发展后（7-11 天），给小鼠静脉注射 Cy3-替拉诺肽，然后进行体内和体外荧光成像。使用双光子成像、免疫荧光和免疫组织化学来鉴定小鼠组织中的关节和滑膜巨噬细胞（CD206、F4/80 和 Cy3-替拉诺肽结合）。Cy3-替拉诺肽的荧光在关节炎小鼠的膝盖和肘部组织中可见；骨骼未观察到放射学变化。然而，组织病理学和免疫组织化学（F4/80）、免疫荧光（CD206）和 Cy3-替拉诺肽结合显示出明显的炎症性关节炎变化。在人类 RA 滑液中，Cy3-替拉诺肽染色与 CD206/CD16 细胞相关；OA 样本中观察到的标记可忽略不计。Cy3-替拉诺肽与 CD206 共定位，与 OA 或 HV 相比，RA 滑膜组织中的染色明显更高。我们的结果表明，使用 Cy3-替拉诺肽进行成像可以在早期关节炎动物模型和人类 RA 患者中检测到体内炎症性 CD206 巨噬细胞。这些数据为早期关节炎的临床前研究建立了一种新工具，并为人类早期 RA 的检测和治疗效果的监测提供了依据。
