Figure 1. Cell morphology and proliferation of human salivary gland (SG)-derived clonal cells.

(a) Three representative clonal cell populations (C1, C2, and C3) were isolated from SGs. The cells were stained with crystal violet for clear visualization. Each clonal population showed a fibroblast-like appearance and the morphological consistency was maintained during subculture. Magnification in each panel is 100×. (b) The clonal cells constantly proliferated during long-term culture and exhibited clonal variations in the proliferation activity. (c) Sphere-forming activity was compared. The isolated clones showed different sphere-forming activity under floating cell culture conditions. The clonal population of C1 and C2 formed larger spheres within 7 days of culture than C3. Human MSCs derived from bone marrow (BM-MSC) were compared as controls. Magnification in each panel is 200×. (d) Spherical diameters were measured at the indicated time points, showing the better sphere-forming activity of C1 and C2. Results are presented as the means ± SEM. One-way ANOVA, Tukey’s post hoc multiple comparison test (**p < 0.01, ***p < 0.001).