FIG. 3.

Effect of IFN-γ or IFN-γ-LPS on the growth of C. trachomatis L2 and C. muridarum MoPn (A) and on the expression of iNOS and IDO (B) in THP-1 monocyte cells. THP-1 cells were untreated or pretreated with IFN-γ (20 U/ml) or IFN-γ (20 U/ml)-LPS (20 ng/ml) for 24 h, infected with chlamydiae, and then incubated in the complete culture medium described in Table 1. Cultures were harvested and processed for the various assays as described in the legend to Fig. 1. Growth data are presented as IFU (log₁₀) and represent the means ± standard errors of triplicate determinations. *, P < 0.0001 compared to the untreated control culture.