Figure 6. α-Toxin reduces the production but not cell viability of mature neutrophils in vitro.

A total of 5 × 10⁴ sorted CD11b⁺Gr-1^high cells (A), n = 6 per condition), 7.5 × 10⁵ CD11b⁺Gr-1^high-cell-depleted bone marrow cells (BMCs) (B–F), n = 3 per condition), or 1 × 10⁵ CD11b⁻Gr-1⁺ cells (G) were cultured for 24 hours in the presence or absence (Control) of 100 ng/ml α-toxin (WT) or a variant α-toxin (H148G). The number of viable cells per culture well was counted after trypan blue staining (A). Representative flow cytometry profile (B,G), the frequency and absolute number of CD11b⁺Gr-1^high neutrophils per culture well (C,D), and the frequency and absolute number of CD11b⁺Gr-1^low neutrophils per culture well (E,F) are shown. Freshly isolated BMCs were used as the gating reference (B). Values are mean ± standard deviation. One-way analysis of variance was employed to assess statistical significance.