PMC

Figure 1. Challenges encountered by Salmonella. The text boxes represent the various stresses encountered by Salmonella during its life cycle and the open text describes the factors and signals generated by Salmonella in order to combat these stress conditions.

Figure 3. Immune evasion strategies of Salmonella. The intracellular life-cycle of Salmonella includes the entry of the bacterium in the host cell, SCV formation (whose pH changes from 6.5 to 5.5 depicted by change in the color of SCV compartment), evasion of host immune response and ultimately host cell death by apoptosis. The text in dark blue shows the immune responses and processes within the host cell that take place during Salmonella infection and text in dark red depicts the factors that help Salmonella to evade these immune responses.

Figure 2. Breaching of gut epithelia by Salmonella. The mode of entry of Salmonella in gut lumen varies according to type of cell encountered on the gut epithelium. The M cells take up the bacteria by means of receptor mediated endocytosis, whereas dendritic cells engulf them by phagocytosis. The membrane of epithelial cells is modified by the action of SPI1 to facilitate the entry of bacteria. Once inside the gut lumen, Salmonella is being taken up by macrophages, T cells, B cells, neutrophils, etc.