Fig 1.
Depletion of CD4+ T cells reactivates chronic lymphatic Mtb infection.
Naïve B6 mice were infected i.d. with 1×104 Mtb H37Rv. At weekly intervals, mice received intraperitoneally (i.p.) a mAb against mouse CD4 (GK1.5) or PBS (A). On day 28 p.i mice were sacrificed and ear-draining LNs, spleen and lung were assessed for numbers of CD4+ T cells by FACS (B) and numbers of viable bacteria (C). Results are presented as pooled data means ± SEM from one representative experiment (n = 4 mice per group). Statistical analyses: Mann-Whitney U-test per organ; significant differences are indicated by asterisks: ** p<0.01; *** p<0.001.
Fig 2.
Non-CD4 immune cells can be numerically expanded by treatment with IL-2/anti-IL-2 complexes.
Naïve B6 mice (A, D) and anti-CD4-treated B6 mice (C, E) were treated i.p. with IL-2/anti-IL-2 complexes on seven consecutive days (A). One day after the last administration, mice were sacrificed and numbers of CD3+CD8+, CD3+CD8+CD44+, CD3+CD8+CD44+, CD3+CD4−CD8− (DN) and CD3−NK1.1+ cells in spleen (B, D, E) and lung (C) were assessed by FACS. Results are presented as pooled data means ± SEM from two pooled independent experiments (n = 8 mice per group). Statistical analyses: One-way ANOVA followed by Bonferroni multiple comparison test for non-parametric samples; significant differences are indicated by asterisks: ** p<0.01; *** p<0.001; n.s. not significant.
Fig 3.
Expansion of non-CD4 immune cell populations fails to reverse reactivation of lymphatic LTBI.
Naïve B6 mice were infected i.d. with 1×104 Mtb H37Rv. In weekly intervals mice received a depleting mAb against mouse CD4 (GK1.5) or PBS i.p. One group of mice received IL-2/anti-IL-2 complexes i.p. on seven consecutive days (A). On days 14, 28, 50 and 125 p.i. mice were sacrificed and ear draining LNs, spleen and lung were assessed for numbers of viable bacteria (B–D) and numbers of CD3+CD4+, CD3+CD8+CD44+ and CD3−NK1.1+ cells (E). Serum concentrations of cytokines (F) and lung pathology (G) were determined. Results are presented as pooled data means ± SEM (B–D, G), individual data points (E), fold upregulation relative to untreated controls (F) and representative images (G) from three pooled independent experiments (n = 7–10 mice per group).
Fig 4.
T cell anergy does not explain failure to reverse Mtb reactivation.
Naïve B6 mice were infected i.d. with 1×104 Mtb H37Rv. In weekly intervals, mice received a depleting mAb against mouse CD4 (GK1.5) or PBS i.p. One group of mice received IL-2/anti-IL-2 complexes i.p. on three consecutive days (A). On days 14, 28, 50 and 125 p.i., mice were sacrificed and ear-draining LNs, spleen and lung were assessed for numbers of viable Mtb (B–D). Additionally, serum cytokine concentrations (E) and lung pathology (F) were determined. Results are presented as pooled data means ± SEM (B–D, F), fold upregulation relative to untreated controls (e) and representative images (f) from two pooled independent experiments (n = 7–10 mice per group).