FIG 6.

Decreased adherence of ΔrafX mutant R6 to MLE12 cells and HUVEC. Adherence of bacterial strains to MLE12 cells (A) or HUVEC (B). ΔEL4, H106A, H306A, and WL denote the ΔrafX mutant complemented with the RafX ΔEL4, RafX H106A, and RafX H306A variants and full-length RafX, respectively. For blocking experiments with rabbit anti-CWPS serum, bacteria were treated with a 1:100 dilution of anti-CWPS serum or normal rabbit serum (NRS) for 30 min before infection. Data are from four independent experiments. Error bars indicate standard deviations. *, P < 0.05; **, P < 0.01; ***, P < 0.001. Flow cytometry histograms for pneumococcal surface protein CbpA in strains R6 (C) and TIGR4 (D) are shown. The control (con) was WT bacteria incubated with normal mouse serum and probed with a PE-labeled secondary antibody.