Figure 1.

The IDO-inhibitor 4-PI inhibits C. trachomatis growth independent of IFN-γ. Cell were left untreated (upper panel) or pre-treated with 50 ng ml⁻¹ IFN-γ treated (lower panel) and incubated for 24 h in the absence or presence of either 1 μM L-1-methyl tryptophan (1-MT), 100 μM or 1 mM 4-Phenyl imidazole (4-PI). The cells were infected after 24 h with an MOI of 1 and were fixed in methanol after 24 h p.i. The fixed cells were stained with an FITC-conjugated antibody against C. trachomatis and counterstained with Evans blue. Representative images (200× magnification fluorescence) are shown.