Fig. 2: 3-HKA is generated in vivo and in vitro following IFN-γ treatment.

a, b Quantification of 3-HKA in lymph and plasma before and after i.p. injection of IFN-γ (5 μg). Lymph (n = 3 biologically independent samples) and blood samples (n = 3 and n = 5 biologically independent samples) were statistically analyzed using a two-tailed paired or unpaired student’s t test. c Quantification of 3-HKA in the plasma of C57BL/6J mice and Ido1 ko mice. Average ± SD of n = 4 biologically independent samples, statistically analyzed using a two-tailed paired student’s t test. d Nodal mouse LECs were cultured in serum-free media for 12 or 24 h with the indicated cytokines. 3-HKA is reported as average concentration ± SD of n = 3 biologically independent samples, statistically analyzed using a two-tailed paired student’s t test. e Nodal and dermal human LECs and mouse dermal LEC were cultured in serum-free media for 24 h with or without IFN-γ (100 ng/ml) or LPS (1 μg/ml). 3-HKA concentration is reported as average concentration ± SD of n = 4 biologically independent replicates statistically analyzed using a two-tailed paired student’s t test. f Dermal mouse LECs were cultured in serum-free media for 24 h with or without IFN-γ (100 ng/ml) or LPS (1 μg/ml). Data are reported as average 3-HKA concentration ± SD of n = 4 biologically independent replicates, statistically analyzed using a two-tailed paired Student’s t test. g, h, i Mouse blood endothelial cells (BEC) and fibroblast reticular cells (FRC) were cultured in serum-free media for 24 h with or without IFN-γ (100 ng/ml) and supernatant analyzed as in (e). i Mouse splenic CD11c-purified dendritic cells (DCs) were cultured in serum-free media for 24 h with or without IFN-γ (50 ng/ml) or LPS (1 μg/ml) and supernatant analyzed as in (e). Data are reported as average 3-HKA concentration ± SD of n = 3 biologically independent replicates, analyzed using a two-tailed paired Student’s t test. j, k Mouse 4T1 and TSA breast carcinoma and human A549 lung and T47D breast carcinoma cells were analyzed for the presence of Trp metabolites (percentage of each metabolite in the supernatant is reported color-coded for each line). 3-HKA concentration ± SD of n = 3 biologically independent replicates. Source data for (a–k) are provided as Source data file.