Fig. 3.

CD28SA treatment during M. tuberculosis infection increases the percentage of CD25⁺Foxp3⁺ T-cells but has no major effect on bacterial burden. a BALB/c mice were treated i.p. with CD28 superagonist (CD28SA, D665, 50 μg/mouse) or isotype control (MOCP31) either ½ week prior (CD28SA once) or ½ week prior and 1 week (CD28SA twice) post aerosol with 100 CFU/lung of M. tuberculosis. Mice were bled at 1½ week and killed at 2 and 10 weeks post-infection. b Expression of CD25⁺ and Foxp3⁺ on CD4⁺-gated cells was measured by flow cytometry in collagenase-treated lung and in peripheral blood lymphocytes. The percentage of CD3⁺ lung cells producing IL-10 and IFN-γ are also represented. Lung cells were harvested following collagenase treatment and stimulated with PMA and ionomycin in the presence of monensin for 4 h and subjected to intracellular staining. c The bacterial load in lungs, spleen, and liver were determined at 2 and 10 weeks post M. tuberculosis infection. Data are presented as log₁₀ CFU per organ. Individual bacterial titers are given together with group medians. Statistical analysis was performed using an unpaired two-tailed Student’s t-test. Data are represented as means ± SEM (n = 5 mice/group; *P < 0.05, **P < 0.01, ***P < 0.001). All data are obtained from one experiment