摘要：It is well known that steric stabilization of the surface of liposomes by a polyethyleneglycol (PEG) - conjugated lipid results in reduced recognition of the liposomes by the cells of the mononuclear phagocyte systems (MPS) and consequently extends their circulation times (t1/2 ≈ 20h in rat). Recently, we reported the “accelerated blood clearance (ABC) phenomenon”, causing PEGylated liposomes (sterically stabilized liposomes, SL) to be cleared very rapidly from the circulation upon repeated injections. Our study suggested that the selective binding of IgM, induced by the first dose of SL, to the second dose of SL and the subsequent complement activation by IgM resulted in accelerated clearance of the second dose. The present paper describes the mechanism of the ABC phenomenon in terms of its interaction with biological factors.
