FIG 4.

P27 favors the survival of M. smegmatis and impairs the phagosome maturation in bovine macrophages. (A) M. smegmatis survival in BMDMs assessed by CFU is shown. Infections were performed with M. smegmatis wild type (white bars) or M. smegmatis overexpressing P27 (striped bars) for 4 and 24 h. Data represent the means ± the SD of three independent experiments. Asterisks indicate significance (*, P ≤ 0.05). (B) BMDMs were infected with M. smegmatis wild type and M. smegmatis overexpressing P27, both labeled with rhodamine (red), for 1 h of uptake, followed by 1 h of chase. The cells were fixed and subjected to indirect immunofluorescence with an antibody to LAMP-3 (green). Scale bars, 10 μm. The inset shows the M. smegmatis phagosomes associated with LAMP-3. (C) Quantitative analysis of the LAMP-3 association with M. smegmatis wild type or M. smegmatis overexpressing P27-containing phagosomes in BMDMs after 2 h of infection. The data represent means ± the SEM of three independent experiments (**, P ≤ 0.01 [two-tailed Student t test]).