FIG 4.

GBS ST-17 virulence gene expression levels compared across cell exposure categories. The expression levels of four virulence genes upregulated upon host cell attachment (Fig. 3) were examined after exposure to amnion cells isolated from human placental tissues and compared to the expression levels seen after decidual and lung epithelial cell exposure. The genes were categorized as “attachment,” “invasion,” or “other” according to their function (see Table 2). (A) Virulence gene expression of the invasive ST-17 strain. (B) Virulence gene expression of the colonizing ST-17 strain. Dashed lines mark a 2-fold change in expression. Bars represent means ± SD of the results of three independent experiments. Asterisks indicate significant differences in gene expression levels between exposures for each gene (*, P < 0.05; **, P < 0.01).