A better understanding of cell-cell and cell-niche interactions is crucial to comprehend the complexity of inflammatory or pathophysiological scenarios such as tissue damage during viral infections, the tumour microenvironment and neuroinflammation. Optical clearing and 3D volumetric imaging of large tissue pieces or whole organs is a rapidly developing methodology that holds great promise for the in-depth study of cells in their natural surroundings. These methods have mostly been applied to image structural components such as endothelial cells and neuronal architecture. Recent work now highlights the possibility of studying immune cells in detail within their respective immune niches. This Review summarizes recent developments in tissue clearing methods and 3D imaging, with a focus on the localization and quantification of immune cells. We first provide background to the optical challenges involved and their solutions before discussing published protocols for tissue clearing, the limitations of 3D imaging of immune cells and image analysis. Furthermore, we highlight possible applications for tissue clearing and propose future developments for the analysis of immune cells within homeostatic or inflammatory immune niches.

中文翻译：

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组织清除和 3D 成像 - 将免疫细胞置于环境中。

更好地了解细胞-细胞和细胞-生态位相互作用对于理解炎症或病理生理学情况的复杂性至关重要，例如病毒感染期间的组织损伤、肿瘤微环境和神经炎症。大组织块或整个器官的光学清除和 3D 体积成像是一种快速发展的方法，对于深入研究自然环境中的细胞具有广阔的前景。这些方法主要应用于图像结构组件，如内皮细胞和神经元结构。最近的工作现在强调了在其各自的免疫环境中详细研究免疫细胞的可能性。本综述总结了组织清除方法和 3D 成像的最新进展，重点是免疫细胞的定位和量化。在讨论已发布的组织清除方案、免疫细胞 3D 成像和图像分析的局限性之前，我们首先提供所涉及的光学挑战及其解决方案的背景。此外，我们强调了组织清除的可能应用，并提出了分析稳态或炎症免疫龛内免疫细胞的未来发展。