The distribution of SAa2-3Gal expression on the primary CTE cells was determined by the staining with a plant lectin, MAA (EY Laboratories). The ciliated cells were revealed by the intense fluorescent microvilli, labeled by the b-tubulin specific antibody [13] . Mucin 5AC glycoprotein and cytokeratin-14 (K14) were the specific markers for the goblet and basal cells, respectively [14, 15] . Immunocytochemistry (ICC) staining illustrated that most btubulin + cells expressed SAa2-3Gal terminal glycan (ratio of MAA + /b-tubulin + cells, 0.8760.06, n = 317) (Fig. 1A) . In a high magnification field, the intense spots of MAA signal were surrounded by cilia bundles on the ciliated cells (Fig. 1B) . In addition, MAA lectin could also be detected on the primary K14 + basal cells (ratio of MAA + /K14 + cells, 0.4660.12, n = 267) (Fig. 1G) .