FIG 3.

Survival of M. avium subsp. paratuberculosis ΔsigL in bovine macrophages. Naive (A) and IFN-γ-pretreated (B) MDM were infected with M. avium subsp. paratuberculosis ΔsigL and wild-type M. avium subsp. paratuberculosis. Cells were lysed at 1, 4, and 8 days postinfection, and numbers of viable bacilli were determined by serial dilutions for CFU plating. Survival was determined as the viable counts at 4 and 8 days relative to the viable counts at day 1. Data are the averages for macrophage infections in three different donor animals; significance levels were determined with Student's t test (*, P < 0.05). Error bars represent standard deviations.