Objective To explore the effects of osmotic pressure on biomechanical properties and immune function of immature dendritic cells (imDCs) from mechanobiological viewpoint. Methods After treated with different osmotic pressures, the cell viability of imDCs was detected using cell counting kit-8 (CCK-8). The changes in morphology of imDCs were observed under laser scanning confocal microscope. Cell electrophoresis was applied to detect the changes in cell electrophoresis mobility. The membrane fluidity of the cells was detected by fluorescence polarization method, and the expression changes of immune-related molecules were detected by real-time fluorescent quantitative PCR (qPCR). The phagocytic ability of the cell was detected by flow cytometry. ResultsBoth hyperosmosis and hypoosmosis could remodel the cyoskeletonof cells, even induce apoptosis. The electrophoresis mobility of the hypoosmosis group was significantly higher than that of the normal osmolarity group, while that of the hyperosmosis group was lower than that of the normal osmolarity group (P<0-05). Fluorescence polarization results showed that both hyperosmosis and hypoosmosis could significantly decrease the membrane fluidity of cells (P<0-05). The results of qPCR detection showed that both hyperosmosis and hypoosmosis could significantly increase the expression of CCR7, CD40, CD205, CD11a, CD11c on the surface of DCs, and the phagocytosis of cell was increased (P<0-05). Conclusions Hypertonic and hypotonic stress can influence biomechanical properties of imDCs and expression of immune-related molecules. The research findings are important for further understanding the immune regulation function of DCs.