Endotoxin enhanced adjuvant effect of liposomes, particularly when antigen and endotoxin are incorporated within the same liposome.

Endotoxin has been shown to enhance the adjuvant effect of liposomes to protein antigens. When a weak antigen and endotoxin were associated with the same liposomes, antibody production could be detected 3 days (72 hours) after injection of the antigen-liposome-endotoxin preparation. When antigen and endotoxin were associated with different liposomes and these antigen-liposome and endotoxin-liposome preparations were injected simultaneously, the adjuvant effect of the liposomes was enhanced also, but not enough to detect antibody production on day 3.