TLR4 and escherichia coli infection: The phagocytosis-promoting receptors were upregulated after E. coli infection, including complement receptor (CR1, CR3, and iC3b), integrins (αMβ2, αVβ3, and αVβ5), toll-like receptor (TLR2, TLR4, and TLR6), might accelerate the phagosome maturation (Figure 6).