Quantifying the total number of CD4+ Tregs in the four groups of mice (uninfected, MTB-infected alone, and MTB-infected mice recipient of Tregs from air- or CS-exposed mice), we found that compared to uninfected mice, MTB-infected mice had significantly more total Tregs, which peaked at Day 30 after infection (Supplementary Figure 3A). This evidence concerns the gene CD4 and infection.