TNF and infection: IL-10 plays at least three major roles during Mtb infection (Figure 1): (1) IL-10 inhibits the production of TNF-α through modulation of STAT3 transcription factors during TNF-α mRNA transcription [35]–[44], (2) IL-10 inhibits the production of chemokines by immune cells, resulting in indirect regulation of cellular recruitment to the site of infection [45]–[48], and (3) IL-10 works in concert with other regulatory mechanisms, such as CTLA-4 and transforming growth factor-β, in order to suppress cellular function, e.g. down regulation of activated macrophages [22], [23], [28], [49]–[51].