FIG. 4.

Intracellular growth of the iLLO strain in J774 cells. Infection of J774 cells was done as described in Materials and Methods. (A) J774 cells were infected with iLLO (DP-L3885) or LLO-negative (DP-L2161) bacteria in the absence of IPTG. (B) iLLO (DP-L3885) or wild-type (10403S) bacteria were grown for 2.5 h in BHI broth containing 1 mM IPTG prior to infection of J774 cells and maintained in tissue culture medium containing 10 mM IPTG throughout the intracellular growth period.