TLR5 and viral infectious disease: Moreover, some investigations described generally impaired TNF-α production in stimulated preterm and term CB mononuclear cells [22,23,24,25], while others reported attenuated immune responses upon activation of TLR1/2, TLR2/6, TLR4, and TLR5 signaling but robust responses to ligands mimicking viral infection, such as the TLR3 ligand poly(I:C) [26,27,28,29].