TLR5 and infection: Legionella begins to stimulate the NF-κB signaling pathway of host cells again after early infection and keeps it in a relatively high and sustained active state, even up to 30h after infection, during which the activation is dependent on a large number of specific Dot/Icm effectors (e.g., sdbA and lubX) but not the flagellin, TLR5 and MyD88 [159].