State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences , Shenyang 110016, China.
Langmuir. 2014 Feb 18;30(6):1609-21. doi: 10.1021/la4042524. Epub 2014 Feb 4.
Fc receptor-mediated macrophage phagocytosis against cancer cells is an important mechanism in the immune therapy of cancers. Traditional research about macrophage phagocytosis was based on optical microscopy, which cannot reveal detailed information because of the 200-nm-resolution limit. Quantitatively investigating the macrophage phagocytosis at micro- and nanoscale levels is still scarce. The advent of atomic force microscopy (AFM) offers an excellent analytical instrument for quantitatively investigating the biological processes at single-cell and single-molecule levels under native conditions. In this work, we combined AFM and fluorescence microscopy to visualize and quantify the detailed changes in cell morphology and mechanical properties during the process of Fc receptor-mediated macrophage phagocytosis against cancer cells. Lymphoma cells were discernible by fluorescence staining. Then, the dynamic process of phagocytosis was observed by time-lapse optical microscopy. Next, AFM was applied to investigate the detailed cellular behaviors during macrophage phagocytosis under the guidance of fluorescence recognition. AFM imaging revealed the distinct features in cellular ultramicrostructures for the different steps of macrophage phagocytosis. AFM cell mechanical property measurements indicated that the binding of cancer cells to macrophages could make macrophages become stiffer. The experimental results provide novel insights in understanding the Fc-receptor-mediated macrophage phagocytosis.
Fc 受体介导的巨噬细胞吞噬癌细胞是癌症免疫治疗的重要机制。传统的巨噬细胞吞噬研究基于光学显微镜，由于 200nm 的分辨率限制，无法揭示详细信息。在微观和纳米尺度上定量研究巨噬细胞吞噬作用仍然很少。原子力显微镜 (AFM) 的出现为在自然条件下定量研究单细胞和单分子水平的生物过程提供了一种极好的分析仪器。在这项工作中，我们结合原子力显微镜和荧光显微镜来可视化和定量研究 Fc 受体介导的巨噬细胞吞噬癌细胞过程中细胞形态和力学性能的详细变化。通过荧光染色可以区分淋巴瘤细胞。然后，通过延时光学显微镜观察吞噬作用的动态过程。接下来，在荧光识别的指导下，应用 AFM 研究巨噬细胞吞噬作用过程中的详细细胞行为。AFM 成像揭示了巨噬细胞吞噬作用不同步骤中细胞超微结构的独特特征。AFM 细胞力学性能测量表明，癌细胞与巨噬细胞的结合可以使巨噬细胞变得更硬。实验结果为理解 Fc 受体介导的巨噬细胞吞噬作用提供了新的见解。
