Figure 2. The appearance of CK14, ALP, p75NGFR, amelogenin, and Notch2 in dental epithelial progenitor cells as revealed by immunostaining. (A) (a-c) CK14 and ALP double-staining. CK14 was continuously expressed in all cells, and ALP-positive cells appeared in the superficial layer (arrows). (d-f) p75NGFR and amelogenin double-staining. Some cells expressing p75NGFR also expressed amelogenin (arrows). (g-i) p75NGFR and ALP double-staining. Cells expressing p75NGFR were not identical to ALP-positive cells. (j-k) Notch2 and ALP double-staining. Many Notch2-positive cells did not express ALP, but some weak ALP-positive cells expressed Notch2 receptors. (l-m) FGFR1 and FGFR2 double-staining. FGFR1 and FGFR2 were continuously expressed in all cells. Bars = 50 µm. (B) Observation of ALP-positive cells by confocal microscope. ALP-positive cells (green) were seen as larger squamous cells in the superficial layer. Lower and light panels show the vertical pictures of the a-b line and c-d line, respevtively. Bar = 25 µm.