Fig. 2.

Role of the complete outer-core region of P. aeruginosa LPS in internalization by airway epithelial cells (2). Bars indicate the mean of the determinations and error bars the SD. (A and B) Assays with bacterial strains of defined LPS phenotype (9); 1, PAC1 R, wild-type, smooth; 2, PAC557, complete core; 3, PAC1R algC::tet, incomplete core; 4, PAC605, incomplete core; 5, PAO1, wild-type, smooth; 6, AK44, complete core; 7, PAO1 algC::tet, incomplete core; and 8, AK1012, incomplete core. All eight strains were internalized by the CFT1-LCFSN cell line significantly better than by the three cell lines expressing mutant ΔF508 CFTR (P < 0.001, ANOVA; P < 0.05 for all pair-wise comparisons, Fisher PLSD). Bacterial strains with a smooth or complete-core LPS were internalized by all of the cell lines significantly better than strains expressing an incomplete core (P < 0.01, ANOVA; P < 0.05 for all pair-wise comparisons, Fisher PLSD). (C to E) Increased internalization by airway epithelial cells of recombinant LPS-smooth P. aeruginosa strains carrying cloned rfb genes (solid bars) compared with parental clinical isolates expressing an incomplete LPS structure and carrying only the DNA cloning vector (open bars) (10). (C) Strain 2192; (D) strain 332; (E) strain 9125. Ingestion of all of the LPS-smooth strains by all of the cell lines was significantly better than ingestion of the corresponding LPS-incomplete isolate (P ≤ 0.002, unpaired t test), except for strain 9125 by the CFT1 cells. There was also significantly greater (P < 0.001, ANOVA) uptake of all of the LPS-smooth bacteria by the CFT1-LCFSN cells compared with the other three cell lines expressing ΔF508 CFTR.