ARG1 and infection: Infection of DUSP4−/− mice with Toxoplasma gondii, another intracellular protozoal pathogen, mirrored the increased susceptibility to infection observed in the L. mexicana model in terms of increased parasite burden, reduced NO production and increased expression of arginase-1; however, in the case of T. gondii infection in Dusp4−/− mice, high arginase-1 levels contribute to parasite control, likely through depletion of L-arginine [53].