The primary response dominates the memory-derived secondary response during Mtb infection.

<p><b>(a)</b> Experimental strategy for adoptive co-transfer experiments. Relative proportion of naïve and memory TB10Rg3 CD8⁺ T cells and their expression of CD62L, KLRG1, and IL-7R before transfer <b>(b)</b> and in the spleen 1d after transfer into uninfected mice <b>(c)</b>. Baseline labeling with the eFluor450 proliferation dye is shown. <b>(d)</b> Concatenated histograms of eFluor450 staining of naïve and memory-derived TB10Rg3 cells in the MLN, lung, and spleen (top) and their CD62L and CD44 expression (bottom) from a representative experiment on d11 post-infection. <b>(e)</b> Proportion of adoptively-transferred memory (Thy1.1⁺) and naïve (Thy1.2⁺)-derived TB10Rg3 CD8⁺ T cells in the lung 15, 18, or 21d after Mtb infection. <b>(f)</b> The relative proportion of memory (Thy1.1) and naïve (Thy1.2)-derived TB10Rg3 CD8⁺ T cells in the MLN, lung, and spleen after infection, compared to spleens from uninfected mice 1 day after transfer (CTRL) (top). Cell numbers of memory (Thy1.1⁺) and naïve (Thy1.2⁺)-derived TB10Rg3 CD8⁺ T cells from the same mice (bottom). (<b>g</b>) KLRG1 and IL-7R expression by memory and naïve-derived TB10Rg3 cells recovered from lung at each time point. <b>(h)</b> TCR Vα2 median fluorescence intensity (MFI) (median ± SEM) in memory and naïve-derived TB10Rg3 CD8⁺ T cells from the same mice at d15 and d18 post-infection. <b>(i)</b> EdU uptake (mean ± SEM) by memory and naïve-derived TB10Rg3 cells recovered from lung. EdU uptake was compared with a student’s t-test. * p < 0.05, ** p < 0.01, <b>***</b> p < 0.001, **** p < 0.0001 n.s. not significant, n.d. < 10 cells detected. Data are representative of 2–10 independent experiments, each with 3–4 mice per group.