FIG. 3.

Macrophages are present in fewer numbers throughout M. tuberculosis infection in the CCR2-deficient mice. The extent of migration of macrophages (A) and neutrophils (B) to the lung after aerosol infection (50 CFU) with M. tuberculosis H37Rv in CCR2^−/− mice (□) and CCR2^+/+ mice (▴) is charted. Flow cytometric analysis was performed on single-cell suspensions of the lung. Within the macrophage/granulocyte gate (determined by side-scatter versus forward-scatter parameters), macrophages were defined as CD11b⁺ Gr1⁻ and neutrophils were defined as CD11b⁺ Gr1⁺. Each datum point represents three to four mice, and the bars represent the standard error. ✽, P ≤ 0.05; ✽✽, P ≤ 0.005; ✽✽✽, P ≤ 0.001. The experiment was repeated twice with similar results.