Horonushi Dan, Suzuki Souta, Ando Maiha, Yuki Haruka, Yasuda Kenji
Department of Pure and Applied Physics, Graduate School of Advanced Science and Engineering, Waseda University, Tokyo, 169-8555, Japan.
Department of Physics, School of Advanced Science and Engineering, Waseda University, Tokyo, 169-8555, Japan.
Sci Rep. 2025 May 30;15(1):19079. doi: 10.1038/s41598-025-03655-8.
The zipper mechanism explains phagocytosis as sequential ligand-receptor interactions between macrophages and antigens, followed by the cell membrane extension for phagosome formation. Hence, the ability of macrophages to innate immunity is restricted by their capacity for engulfment related to the expansion limit of their membranes. However, the maximum expansion ability of macrophage membranes and their relationship with the phagocytosis capacity has not been rigorously investigated yet because of the lack of quantitative measurement methods of maximum cell expansion. Here, we have developed an opsonized capillary tube assay and evaluated the maximum membrane extension on the opsonized inner surface of capillary tubes from the inner round area attached to the macrophage surface. When the engulfment started, the cell membrane in the inner circle of the capillary head expanded up to 10.64 times in opsonized capillary tubes regardless of the inner diameter differences of 3 to m. This maximum expansion ability was two times larger than those reported in the frustrated phagocytosis experiments. To support this result, we confirmed the independence of simultaneous local phagocytic responses against multiple antigens and the phagocytic ability of the outer surfaces of extending phagocytic cups. We applied this maximum expansion capacity to the opsonized microneedle phagocytosis and estimated that the required cell membrane for phagocytosis to reach the maximum expansion was up to m area around the attached antigen. The maximum number of engulfed m microbeads during the serial phagocytosis was 24% consume of their maximum ability of membrane extensions, suggesting that serial phagocytosis may involve another phagocytosis-number-dependent regulatory mechanism, adding to the zipper mechanism to understand the determination of phagocytosis capacity.
拉链机制将吞噬作用解释为巨噬细胞与抗原之间的配体-受体相互作用序列，随后细胞膜延伸以形成吞噬体。因此，巨噬细胞的先天免疫能力受到其吞噬能力的限制，而吞噬能力与细胞膜的扩张极限有关。然而，由于缺乏最大细胞扩张的定量测量方法，巨噬细胞膜的最大扩张能力及其与吞噬能力的关系尚未得到严格研究。在这里，我们开发了一种调理化毛细管测定法，并从附着在巨噬细胞表面的内圆区域评估了调理化毛细管内表面上的最大膜延伸。当吞噬开始时，无论内径为3至μm的差异如何，调理化毛细管中毛细管头部内圈的细胞膜都会扩张至10.64倍。这种最大扩张能力比吞噬受阻实验中报道的能力大两倍。为了支持这一结果，我们证实了对多种抗原的同时局部吞噬反应与延伸吞噬杯外表面的吞噬能力的独立性。我们将这种最大扩张能力应用于调理化微针吞噬作用，并估计吞噬作用达到最大扩张所需的细胞膜面积在附着抗原周围高达μm。连续吞噬过程中吞噬的μm微珠的最大数量消耗了其膜延伸最大能力的24%，这表明连续吞噬可能涉及另一种吞噬数量依赖性调节机制，这是对拉链机制的补充，有助于理解吞噬能力的决定因素。
