FcγR-mediated effector pathways during viral infection. Interactions of the IgG Fc domain have pleiotropic effects that contribute to the in vivo protective activity of antibodies during infection. (A) IgG-opsonized viral particles are cleared by FcγR-expressing effector leukocytes, like neutrophils, macrophages, and NK cells. (B) Additionally, IgG binding to infected cells expressing viral proteins on their surface recruits effector leukocytes, such as macrophages and NK cells, through Fc–FcγR interactions. Infected cells are thereby cleared by FcγR-expressing leukocytes, limiting the viral reservoir and preventing further viral spreading. (C) Lastly, IgG–antigen immune complexes generated during these steps have the capacity to stimulate host immune responses through FcγR engagement on DCs, inducing cellular maturation and enhancing antigen presentation to T cells.