M.J. Welsh and A.E. Smith, RAC Application 
Figure 9. Effect of Ad2/BGal-l on primary cultures of normal human airway epithelia. 
Epithelia were stained with X-Gal. Filters are relatively opaque, obscuring cell detail. 
b. Studies with Ad2/CFTR-1 
We also allowed CF airway epithelial cells grown as epithelia on permeable filter supports 
to form a low transepithelial conductance and then infected them with Ad2/CFTR-1. Three 
days after infection at 5 PFU/cell, CFTR was readily detected by immunocytochemical 
staining at the apical membrane (Fig. 10). In contrast, little CFTR was detected in 
uninfected cells or in cells infected with Ad2/BGal-l. 
The most important experiment was to test the ability of Ad2/CFTR-1 to correct the defect 
in transepithelial chloride secretion in CF airway epithelial cells. We infected primary 
cultures of CF nasal polyp epithelial cells with Ad2/CFTR-1 at a multiplicity of 5 PFU/cell. 
Three days after infection, we measured transepithelial chloride secretion in an Ussing 
chamber. Figure 1 1 shows that CF epithelial cells do not secrete chloride upon cAMP 
stimulation (i.e., there is no increase in transepithelial short-circuit current with addition of 
cAMP). In contrast, cAMP agonists stimulated chloride secretion in Ad2/CF 1 R- 1-treated 
CF epithelial cells. This response resembled that of normal nasal polyp epithelial cells and 
was inhibited by the chloride channel blocker, diphenylamine-2-carboxylate. We have 
obtained identical results using primary cultures of CF cells from tracheal epithelium. 
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Recombinant DNA Research, Volume 16 
