Antibody opsonization

Antibody opsonization is when antibodies opsonize a pathogen, making it ready for digestion. This opsonization makes the pathogen vulnerable for phagocytosis because the antibody interacts with the Fc receptor on the phagocyte. Since antibodies also trigger the complement system (and the complement molecules also bind to the pathogen to opsonize it), the pathogen is then doubly vulnerable since the complement can bind to complement receptors such as CR1 on the phagocyte's surface, making it more recognizable as a pathogen.

Also see, Opsonin for more information.