FIG. 5.

Inhibition of IFN-γ-induced IRF-1 expression by L. donovani amastigotes. Adherent BMMs were either infected with freshly isolated L. donovani amastigotes for 18 h at a parasite-to-cell ratio of 20:1 (A and B) or incubated for 5 h with the supernatant of infected BMMs (B). The cells were then stimulated with 100 U/ml IFN-γ for the indicated times. Total cell extracts were analyzed by Western blotting with antibodies against IRF-1 and Akt, as described in Materials and Methods. Densitometric analysis was performed, and IRF-1 band intensities were normalized to those for the Akt control. Results are expressed as the fold difference from the results for the unstimulated, uninfected sample and represent the means ± SDs of five (A) or four (B) independent experiments. **, P < 0.02; ***, P < 0.001.