FIG. 1.

Histological cross sections of HAE and excised human airway tissue samples were probed with anti-β-tubulin IV (red) and the lectin (green) SNA for the human influenza virus receptor (α-2,6-linked sialic acid) or MAA for the avian influenza virus receptor (α-2,3-linked sialic acid). SNA was visible on the apical surface of nonciliated (A) and ciliated cells (B). SNA on ciliated and nonciliated cells was also observed in excised human airway tissue samples (C). MAA was visible on the apical surface of ciliated cells and, to a lesser degree, on nonciliated cells (D). MAA was observed at the apical surface of ciliated cells in paraffin-embedded, excised human airway tissue (E). Arrows, ciliated cells; arrowheads, nonciliated cells.