C5AR1 and bacterial urinary tract infection: To evaluate the contribution of C5aR1 on parenchymal and/or infiltrating cells to the development of infection, we induced UTI in 4 groups of chimeric mice generated by bone marrow transplantation of irradiated recipient mice (denoted as WT→WT, C5aR1–/–→WT, WT→C5aR1–/–, C5aR1–/–→C5aR1–/–).