FIG. 7.

Effect of AdmIFN-γ treatment on intracellular growth of Legionella in macrophages ex vivo. Mice were treated i.t. with AdmIFN-γ (5 × 10⁸ PFU), AdCtl (5 × 10⁸ PFU), or saline. Two days later, alveolar macrophages were recovered from lavage fluid and cultured with L. pneumophila organisms at an MOI of 0.2 to 0.3. Cells were washed and lysed on day 0 following a 2 of coincubation of Legionella and macrophages to determine the level of initial intracellular or cell-associated Legionella organisms. Two and three days later, macrophages were washed and lysed to determine serial CFU counts. Results are expressed as the net percent change in CFU on days 2 and 3 compared to initial (i.e., day 0) CFU. The experiment was performed twice. Statistical significance: ∗∗, P < 0.01 (compared to alveolar macrophages from saline and AdCtl-treated animals); ∗∗∗, P < 0.001 (compared to alveolar macrophages from saline-treated animals). Error bars, standard deviations.