FIG. 6.
Adherence of S. pneumoniae to A549 lung epithelial cells. Mid-exponential-phase S. pneumoniae cells (1 × 106 CFU) were added to A549 cells at a multiplicity of infection of 10 and incubated at 37°C for 30 min. The percentages of the input bacteria that adhered to the monolayers after three washes with PBS were determined. The adherence of mutant strains is expressed relative to the adherence of the wild type. Representative results from one of four independent experiments are shown. The assay was performed in quadruplicate in each experiment, and the error bars indicate the standard deviations.