FIG. 3.

The Vi capsule reduces CR3-mediated interaction with macrophages. (A and B) Binding to (after incubation at 4°C) (A) and phagocytosis of (gentamicin protection assay) (B) capsulated bacteria (the S. Typhi wild type or the S. Typhi vexE mutant complemented with pAS1) and noncapsulated bacteria (an S. Typhi ΔtviB-vexE mutant or an S. Typhi vexE mutant) to human macrophage-like THP-1 cells in the absence (black bars) or presence (open bars) of blocking anti-human CD11b antibodies. (C and D) Binding to (after incubation at 4°C) (C) and phagocytosis of (gentamicin protection assay) (D) the indicated bacterial strains by murine BMDMs from wild-type mice (C57BL/6, black bars) or CR3-deficient mice (open bars). Each experiment was repeated at least three times independently, and data are shown as averages ± standard errors. The statistical significance of the differences is indicated above. NS, not significant.