Fig. 1.

Internalization of P. aeruginosa by 10⁵ transformed airway epithelial cells (2). Cells were grown for 72 hours and bacteria were then allowed to invade the cells for 3 or 4 hours. Bars indicate the mean of the determinations and error bars the SD. Cell lines are as follows: 1, CFT1-LCFSN; 2, CFT1; 3, CFT1-LC3; and 4, CFT1-ΔF508. (A) Cells were grown at 37°C, a temperature that inhibits membrane expression of ΔF508 CFTR (5) and the assay was carried out at 37°C. Multiple comparisons for all three bacterial strains were significant (P < 0.001, ANOVA); the CFT1-LCFSN line was significantly different from any other cell line (P < 0.01, Fisher's PLSD statistic) for all three bacterial strains. (B) Cells were grown at 26°C and internalization was assessed at 26°C. (C) Cells were grown at 26°C and internalization was assessed at 37°C. When cells were grown at 26°C to promote surface expression of ΔF508 CFTR (5), there were no significant (P > 0.2, ANOVA) differences in bacterial uptake among the cell lines for any P. aeruginosa strain tested.