FCGR2A and infection: Studies have shown that infecting Fcγ-receptor (FcγR)—expressing cells in the presence of antibodies from flavivirus-immune donors—can significantly increase the rate of infection.62 This phenomenon, termed antibody-dependent enhancement (ADE), is said to occur when cross-reactive antibodies present at sub-neutralizing concentrations facilitate the uptake of virions by permissive cells, thereby enhancing infection.