The CTE cells were fixed in 4% cold paraformaldehyde and blocked using the Carbo-free TM blocking solution (Vector Laboratories). Immunocytochemistry (ICC) was performed using the biotin-labeled lectins (MAA, MAL I, MAL II, SNA and SNA I, 1:500) or the FITC-conjugated MAA (1:50, EY Laboratories). The used primary antibodies were b-tubulin (1:500, Sigma-Aldrich, St. Louis, MO, USA), mucin 5AC (1:100, Sigma-Aldrich) and cytokeratin 14 (K14, 1:100, Convance, Princeton, NJ, USA). The specificity of the anti-AIV 2838 polyclonal antibodies (1:500, from infected chickens) has been evaluated in our previous report [37] . Appropriate fluorescence-tagged secondary antibodies (2u Ab, Jackson ImmunoResearch, West Grove, PA, USA) and Cy3conjugated streptavidin (Rockland) were used for visualization.