TGFB1 and infection: Several studies have shown that the transforming growth factor β (TGF-β) is produced by macrophages upon infection with Mycobacterium and also with other pathogens and that the presence of TGF-β favors virulence, probably through its immunosuppressive action by impairing the response of macrophages to cytokines such as TNF-α or by suppression of nitric oxide (NO), and reactive oxygen intermediates [12], [13], [14].