Fig. 6.

Levels of cls1 and cls2 mRNA in wt S. aureus SA113 during growth in TSB (A) and after phagocytosis by PMNs (B). Overnight cultures of S. aureus were diluted 100-fold in fresh TSB medium and, after the indicated times in subculture, the levels of cls1 and cls2 mRNA were measured by real-time RT-PCR as described in Materials and Methods, expressed relative to 16S rRNA, and normalized to the 3-h sample. S. aureus harvested after 3 h of subculture in TSB were opsonized by incubation in the presence of 10% human serum for 20 min at 37°C and then mixed with PMN at MOI of 5. Samples for the assay of cls1 and cls2 mRNA were taken before (0 min) and 30 and 120 min after phagocytosis by PMN. The data shown represent means ± the SEM of triplicate determinations from three independent experiments. *, Significant differences as determined by Student t test (P < 0.05).