FIG. 5.

An L. pneumophila mutant lacking all vipD paralogs is proficient for intracellular growth within bone marrow-derived macrophages. (A) Defective growth phenotype of the original L. pneumophila vipD1::miniTn10 strain (strain SV-L1) is lost on moving the mutation into a fresh parental strain background (strain SV48). The wild-type (WT) strain Lp01 is the parent strain for both the vipD mutant strains (SV-L1 and SV48) and the dotA mutant strain (SV8). (B) A strain bearing deletions of vipD, vpdA, vpdB, and vpdC (strain SV221, designated ΔΔΔΔ) does not show a growth defect in murine macrophages. The wild-type strain Lp02 is the parent strain for the quadruple mutant strain and the dotA strain Lp03. (A and B) Bone marrow-derived macrophages (4 × 10⁵ cells per well) were incubated with the indicated strains at an MOI of 0.05 for either 2 h (A) or 1.5 h (B). Viable counts were determined as described in Materials and Methods. The means and standard deviations are shown for each time point; experiments were done in triplicate.