Fig. 4.
Requirement for YopJ, YopB, and the function of the T3SS in BMDM death induced by intracellular Y. pseudotuberculosis. BMDMs were left uninfected (UI) or infected with the indicated Y. pseudotuberculosis strains carrying pYopJ, pYopJC172A, or pYopB2. (A) YopJ expression from intracellular bacteria was either not induced (white bars) or induced with IPTG (checked bars) after 1 h treatment with 8 μg/ml Gm. (B) YopB expression from intracellular ΔyopB/pYopB2 bacteria was not induced (no IPTG) or induced with IPTG (IPTG) after extracellular bacteria were killed with 8 μg/ml Gm for 1 h. The percentage of LDH released into the medium was determined at 24 h postinfection. Data shown are means and SEMs from three independent experiments. P values were determined by two-way analysis of variance, followed by Bonferroni's multiple-comparison test (A) or the Mann-Whitney test (B). *, significant difference (P < 0.05) compared to all the other treatments.