UNILAMELLAR LIPOSOMES MODULATE SECRETION OF TUMOR-NECROSIS-FACTOR BY LIPOPOLYSACCHARIDE-STIMULATED MACROPHAGES

Liposomal encapsulation of antimicrobial agents has been used to impro ve drug delivery, particularly against intracellular pathogens. The ef fect of unilamellar liposomes on macrophage activation in response to Escherichia coli lipopolysaccharide was examined. Liposomes caused a d ose and time-dependent inhibition of tumor necrosis factor release by lipopolysaccharide-treated cells. The accumulation of tumor necrosis f actor mRNA transcripts was unaffected, suggesting a posttranscriptiona l mechanism for this effect. However, induction of macrophage procoagu lant activity was unaffected by liposomes, indicating a selective rath er than a global inhibition. These data suggest that liposomes used fo r drug delivery may modulate the host response to infection.