Figure 5. CD11b⁺ cells mediate improved protection in S100A9KO Mtb-infected mice.

B6 (n = 5–24) and S100A9KO (n = 5–24) mice were aerosol infected with approximately 100 CFU Mtb HN878. (A) CD11b MFI on neutrophils, monocytes, and RMs was determined using flow cytometry at 50, 100, 150, and 300 dpi. S100A9KO (n = 6) infected mice received CD11b⁺ purified cells from B6 mice (50 μL containing 1 × 10⁶ cells) intratracheally at 100 dpi. (B) Lung bacterial burden was determined by plating at 120 dpi. (C) Lung homogenates were analyzed by Luminex for CXCL-1 and CXCL-2 at 300 dpi. Figures depict 1 experiment representative of 2 or combined data from multiple experiments. Data points represent the mean ± SEM of values. (A and C) Student’s t test between B6 and S100A9KO per time point; (B) 1-way ANOVA with Tukey’s posttest. *P ≤ 0.05; ***P ≤ 0.001; ****P ≤ 0.0001.