<i>Nod1^−/−</i> mice display increased susceptibility to renal retrograde UPEC infection.

<p>(A) Bacterial loads in kidneys from WT, <i>Nod1^−/−</i> and <i>Nod2^−/−</i> mice (n = 8 per group) 24 h after the transurethral inoculation of UPEC strain HT7. Horizontal bars are the mean value of each group. (B) Illustrations of the <i>E. coli</i> immunostaining (arrowheads) in the infected WT and <i>Nod1^−/−</i> mice kidneys. Bars = 100 µm. (C) Illustrations of neutrophils infiltrates (arrowheads) in the urinary space from post-infected WT, <i>Nod1^−/−</i>, and <i>Nod2^−/−</i> kidneys. Bars = 100 µm. (D) Levels of MPO activity in kidney homogenates from post-infected WT, <i>Nod1^−/−</i>, and <i>Nod2^−/−</i> mice. (E and F) Flow cytometry analysis of the CD45⁺ leukocyte population infiltrating the infected kidneys from WT and <i>Nod1^−/−</i> mice 24 h after UPEC inoculation. Representative dot-plots of CD45⁺ F4/80⁻ renal cells (E) and percentages (E, upper right insets and F) of F4/80⁻ CD11b⁺ Gr1^HI neutrophils infiltrating the infected WT and <i>Nod1^−/−</i> mice kidneys. The bars indicate the mean percentage of neutrophils over total CD45⁺ leukocytes (<i>n</i> = 3 mice per group. (G) Bacterial loads in kidneys from untreated (–) and day-5 <i>Nod1^−/−</i> mice (n = 8 per group) 24 h after the transurethral inoculation of the UPEC strain HT7. Horizontal bars are the mean value of each group. Values are presented as mean ± SE. *, <i>p</i><0.05 (A, D, Mann-Whitney test; F, G, Two-tailed, unpaired Student's <i>t</i> test).