BioTherapeutics Research Laboratories, Robarts Research Institute and Department of Microbiology & Immunology, University of Western Ontario, London, Ontario, Canada.
Wiley Interdiscip Rev Nanomed Nanobiotechnol. 2013 Sep-Oct;5(5):469-83. doi: 10.1002/wnan.1227. Epub 2013 Apr 30.
Cellular magnetic resonance imaging (MRI) is a means by which cells labeled ex vivo with a contrast agent can be detected and tracked over time in vivo. This technology provides a noninvasive method with which to assess cell-based therapies in vivo. Dendritic cell (DC)-based vaccines are a promising cancer immunotherapy, but its success is highly dependent on the injected DC migrating to a secondary lymphoid organ such as a nearby lymph node. There the DC can interact with T cells to elicit a tumor-specific immune response. It is important to verify DC migration in vivo using a noninvasive imaging modality, such as cellular MRI, so that important information regarding the anatomical location and persistence of the injected DC in a targeted lymph node can be provided. An understanding of DC biology is critical in ascertaining how to label DC with sufficient contrast agent to render them detectable by MRI. While iron oxide nanoparticles provide the best sensitivity for detection of DC in vivo, a clinical grade iron oxide agent is not currently available. A clinical grade (19) Fluorine-based perfluorcarbon nanoemulsion is available but is less sensitive, and its utility to detect DC migration in humans remains to be demonstrated using clinical scanners presently available. The ability to quantitatively track DC migration in vivo can provide important information as to whether different DC maturation and activation protocols result in improved DC migration efficiency which will determine the vaccine's immunogenicity and ultimately the tumor immunotherapy's outcome in humans.
细胞磁共振成像 (MRI) 是一种可以检测和跟踪在体(ex vivo)标记对比剂的细胞随时间在体内(in vivo)的迁移的方法。这项技术为评估基于细胞的治疗方法提供了一种非侵入性的方法。树突状细胞 (DC) 疫苗是一种很有前途的癌症免疫疗法，但它的成功高度依赖于注入的 DC 迁移到二级淋巴器官，如附近的淋巴结。在那里，DC 可以与 T 细胞相互作用，引发肿瘤特异性免疫反应。使用非侵入性成像方式（如细胞 MRI）来验证 DC 的体内迁移是很重要的，这样可以提供有关注入的 DC 在目标淋巴结中的解剖位置和持久性的重要信息。了解 DC 的生物学特性对于确定如何用足够的对比剂标记 DC 以使其可通过 MRI 检测至关重要。虽然氧化铁纳米颗粒提供了检测体内 DC 的最佳灵敏度，但目前尚无临床级氧化铁剂。一种临床级 (19) 氟基全氟碳纳米乳液是可用的，但灵敏度较低，其在人类中检测 DC 迁移的效用仍有待使用目前可用的临床扫描仪来证明。定量跟踪 DC 在体内的迁移能力可以提供重要信息，了解不同的 DC 成熟和激活方案是否会导致 DC 迁移效率的提高，这将决定疫苗的免疫原性，并最终决定人类肿瘤免疫治疗的结果。
