Effects of liposomes of different phospholipid composition on the induction of respiratory burst in human blood monocytes and alveolar macrophages.

Liposomes made from phosphatidylcholine (PC) or PC-fatty acid ester mixtures have been shown to induce an activation of the respiratory burst in human blood monocytes and alveolar macrophages (AM). Incorporation of 1,2-diacylglycerol or arachidonic acid into PC liposomes significantly enhanced the effect. In the case of AM, the effect of PC liposomes was similar to those of phorbol 12-myristate 13-acetate (PMA) and the ionophore A 23187, while in monocytes, PMA and A 23187 induced a stronger respiratory burst than PC liposomes. In the presence of PMA, higher liposomal concentrations were required to produce the maximum activation of the respiratory burst in both types of cells.