TLR4 and infection: Notably, by employing confocal microscopy, we were able to visualize bacteria in tlr4 mutant mice infected with the 105 inoculum; at early timepoints (4 hpi and 2 dpi), bacteria were identified inside cells in the bronchoalveolar lavage fluid (BALF), as well as extracellularly, consistent with our previously published results in the acute infection model (Fig. S2)43.