IDO1 and infection: Treg cells were depleted or the activity of IDO and HO-1 was inhibited since the beginning of infection with mild virulence strain H37Rv, the administration of anti-CD25 antibodies or enzyme blockers was initiated at this time because these regulatory factors started their increase since day 1 and it was relatively stable during the infection, an increase of IFN-γ expression was observed, but this was only significant with Treg cell depletion.