Effect of temperature on immune damage of liposomes prepared in the presence and absence of cholesterol

Abstract

SINCE the report by Kinsky¹ that liposomes containing lipid haptens could be damaged by activated complement, it has become generally accepted that the lytic attack mechanism of the complement system acts on the lipid matrix of the cell membrane. In spite of the accumulation of experimental observations² concerned with liposomal damage by activated complement, there is little detailed information about the mechanism by which the damage occurs. Inoue and Kinsky³ suggested that complement did not damage liposomes as a result of degradation by ‘phospholipase’ (see also ref. 4). It was therefore postulated that the lytic action of complement may resemble that of ‘detergent’^2–4. Hydrophobic regions in the terminal complement components may penetrate into lipid bilayers, diminishing the non-polar inter-molecular attractive forces between lipids. Müller-Eberhard et al.⁵ proposed a model for the molecular assembly of the C5–9 complex on the surface of cells under attack by complement. They suggested that complete assembly of the C5–9 complex augmented the detergent effect of C5.