Although both MAA and SNA bound to the surfaces of a subpopulation of the K14 + cells ( Fig. 1G and Fig. 2B ), their detected signals were relatively weak (Figs. S2A and S2B). To determine whether a single basal cells can express both SAa2-3Gal and SAa2-6Gal, CTE cells were triple-stained with K14 primary antibody (Cy5-2u Ab, purple), FITC-conjugated MAA (green) and biotin-labeled SNA (detected by Cy3-Streptovidin, red) (Figs. 3A, 3B and 3C). Their cell nuclei were revealed by DAPI staining (blue). When viewed in the same field under a confocal microscope, the ICC result indicated that MAA and SNA can be co-expressed on single K14 + cells (indicated by the arrows).