Depletion of lung T _RM leads to increased macrophage responses. (A) Quantification of total CD4⁺ and CD8⁺ T cells in the lungs of mice treated with anti-Thy1.2–depleting Abs (orange) or IgG control Abs (gray). Statistical significance was determined by Student’s t test. Boxes indicate interquartile range with a line drawn at the mean; whiskers indicate the minimum and maximum values. (B) T_RM content in the lungs of T cell–depleted or control mice in A shown in representative flow cytometry plots (left) and compiled results (right) of CD45 expression from IV Ab administration (CD45(IV), left) and CD69 expression (right) by CD4⁺ (top) and CD8⁺ (bottom) T cells. (C) Lung macrophage accumulation after influenza infection in T_RM-depleted (blue) and control (green) mice undergoing secondary infection at 4 dpi compared with uninfected counterparts shown in representative flow cytometry plots (left) and compiled results (right) of F4/80⁺ macrophages in the lungs. Statistical significance for A–C was determined by Student’s t test. (D and E) Pearson’s correlation analyses between T_RM and CD4⁺ and CD8⁺ T_RM subsets with (D) macrophages and with (E) Arg1⁺ macrophages. Data are representative of two independent experiments, with n = 7–10 mice per group. ****P ≤ 0.0001; ***P ≤ 0.001; **P ≤ 0.01; *P ≤ 0.05.