The clearance of liposomes from the circulation is mediated largely by
the cells of the reticuloendothelial system. These cells recognize li
posome-bound immunoproteins, particularly immunoglobulins and compleme
nt. This review addresses the state of knowledge of the plasma protein
s that can initiate complement activation and antibody binding and the
known interactions among these proteins and liposomes, Evidence for t
he involvement of immunoproteins and other molecules in the in vivo su
rvival of liposomes is also reviewed.