Binding of FX to Adv5 increases infection of hepatocytes and enhances activation of macrophages. Adv5 without FX bound is recognized by immunoglobulin M (IgM) and complement and inactivated. This form of virus has a low infectivity and mildly activates the innate immune system by binding to integrins on liver macrophages. Binding of FX to Adv5 enhances infection of liver hepatocytes by increasing the binding of virus to the cells. In addition, Adv5 coated with FX induces a more robust innate immune response in macrophages by activating the TLR4-NF-κB pathway. KC, CXCL1. Professional illustration by Debra T. Dartez.