FIGURE 7.

Akt and Cdc42 are essential for PspC-mediated pneumococcal uptake by primary respiratory host cells. A, adherence of pneumococci was determined by counting the cfu per well obtained from sample aliquots plated onto blood agar plates after 1 h of host cell infection. *, p < 0.02 relative to infections carried out with the wild-type strain. B, immunofluorescence microscopy of S. pneumoniae wild type (WT) and its isogenic PspC mutant attached to primary human respiratory epithelial cells. C, invasion and intracellular survival of pneumococci were determined by the antibiotic protection assay. *, p < 0.02 relative to infections carried out with the wild-type strain. D, invasion and intracellular survival of the bacteria in primary cells human bronchial epithelial cell cells were determined in the absence (Ctrl) or presence of Akt Inhibitor VIII (Akti 1/2, 10 μm) and the presence of Cdc42 inhibitor secramine A (10 μm) by the antibiotic protection assay. *, p < 0.02 relative to infections carried out in the absence of inhibitor.