TLR5 and infection: Recently, infection with L. pneumophila has been shown to induce a biphasic activation of NF-κB in human epithelial cells: (i) early in infection, bacterial flagellin induces signaling of TLR5 and a transient translocation of p65 into the nucleus and (ii) at later time points, an unknown factor that depends on bacterial replication and a functional Dot/Icm system induces continuous nuclear localization of p65 and permanent degradation of IκBα [32].