Dendritic cells (DCs) are professional antigen-presenting cells of the immune system. Upon sensing pathogenic material in their environment, DCs start to mature, which includes cellular processes, such as antigen uptake, processing and presentation, as well as upregulation of costimulatory molecules and cytokine secretion. During maturation, DCs detach from peripheral tissues, migrate to the nearest lymph node, and find their way into the correct position in the net of the lymph node microenvironment to meet and interact with the respective T cells. We hypothesize that the maturation of DCs is well prepared and optimized leading to processes that alter various cellular characteristics from mechanics and metabolism to membrane properties. Here, we investigated the mechanical properties of monocyte-derived dendritic cells (moDCs) using real-time deformability cytometry to measure cytoskeletal changes and found that mature moDCs were stiffer compared to immature moDCs. These cellular changes likely play an important role in the processes of cell migration and T cell activation. As lipids constitute the building blocks of the plasma membrane, which, during maturation, need to adapt to the environment for migration and DC-T cell interaction, we performed an unbiased high-throughput lipidomics screening to identify the lipidome of moDCs. These analyses revealed that the overall lipid composition was significantly changed during moDC maturation, even implying an increase of storage lipids and differences of the relative abundance of membrane lipids upon maturation. Further, metadata analyses demonstrated that lipid changes were associated with the serum low-density lipoprotein (LDL) and cholesterol levels in the blood of the donors. Finally, using lipid packing imaging we found that the membrane of mature moDCs revealed a higher fluidity compared to immature moDCs. This comprehensive and quantitative characterization of maturation associated changes in moDCs sets the stage for improving their use in clinical application.

树突状细胞（DC）是免疫系统的专业抗原呈递细胞。在感知到环境中的致病物质后，DC 开始成熟，其中包括细胞过程，例如抗原摄取、加工和呈递，以及共刺激分子和细胞因子分泌的上调。在成熟过程中，DC 与周围组织分离，迁移到最近的淋巴结，并找到进入淋巴结微环境网络中正确位置的方式，与相应的 T 细胞相遇并相互作用。我们假设 DC 的成熟经过充分准备和优化，导致了改变从力学和代谢到膜特性等各种细胞特征的过程。在这里，我们使用实时变形细胞术测量细胞骨架的变化，研究了单核细胞衍生的树突状细胞（moDC）的机械特性，发现成熟的 moDC 比未成熟的 moDC 更硬。这些细胞变化可能在细胞迁移和 T 细胞激活过程中发挥重要作用。由于脂质构成质膜的组成部分，在成熟过程中需要适应迁移和 DC-T 细胞相互作用的环境，因此我们进行了无偏倚的高通量脂质组学筛选，以鉴定 moDC 的脂质组。这些分析表明，在 moDC 成熟过程中，总体脂质组成发生了显着变化，甚至意味着成熟时储存脂质的增加和膜脂质相对丰度的差异。此外，元数据分析表明，脂质变化与献血者血液中的血清低密度脂蛋白（LDL）和胆固醇水平有关。最后，使用脂质堆积成像，我们发现成熟的 moDC 的膜比未成熟的 moDC 具有更高的流动性。这种对 moDC 成熟相关变化的全面、定量的表征为改善其在临床应用中的应用奠定了基础。