Inhibition of increased indoleamine 2,3-dioxygenase activity attenuates Toxoplasma gondii replication in the lung during acute infection

► The tryptophan-degrading enzyme, IDO was investigated following T. gondii infection. ► Depleted tryptophan in the lung was occurred in wild-type, but not in IDO KO mice. ► The inhibition of increased IDO activity attenuates T. gondii replication. ► The inhibition of increased IDO activity reduced the inflamed damage in the lung. ► Kynurenine pathway may play a key role following T. gondii infection.