Antibodies against viruses: passive and active immunization

Antibodies, through passive or active immunization, play a central role in prophylaxis against many infectious agents. While neutralization is a primary function of antibodies in protection against most viruses, the relative contribution of Fc-dependent and complement-dependent anti-viral activities of antibodies was found to vary between different viruses in recent studies. The multiple hit model explains how antibodies neutralize viruses, and recent data on the stoichiometry of antibody neutralization suggest that the organization of viral surface proteins on viruses, in addition to virus size, influences the level of antibody occupancy required for neutralization. These new findings will improve our strategies in therapeutic antibody engineering and rational vaccine design.