FIG. 6.

Analysis of promoter-hly fusion strains for growth in J774 cells and during murine infection. (A) Representation of the hly fusion to the groESL promoter region in L. monocytogenes gro-hly. (B) Analysis of levels of L. monocytogenes strains in the spleens of infected mice. Mice were infected intraperitoneally with L. monocytogenes gro-hly, L. monocytogenes plc-hly, or L. monocytogenes CGNeg, and bacterial numbers in the spleens were determined at 2 days postinfection. Data are means ± standard deviations for four mice per group. (C) Growth of fusion strains in J774 cells. J774 cells were infected with L. monocytogenes gro-hly, L. monocytogenes plc-hly, or L. monocytogenes CGNeg, and numbers of intracellular bacteria were determined at specific time points postinfection. Data are means ± standard deviations for three wells per time point.