Biological activity of chemically synthesized analogues of lipid A. Demonstration of adjuvant effect in hapten-sensitized liposomal system.

The adjuvant effect of synthetic analogues of lipid A was investigated in tnice in vivo. Two cbf the five synthetic lipid A analogues showed adjuvant activity when they were incorporated into dipalmitoylglyceerophosphocholine-cholesterol-dipalmitoylglycerophosphate liposomes sensitized with trinitrophenylaminocaprcylglycerophospho-ethanolamine. The minimum structure for an adjuvant effect in the liposomal immunogen system was l-mono-phosphate of 6-O-(2-deoxy-2-tetradecanoylamino-6-O-tetradecanoyl-D-glucopyranosyl)-2-deoxy-2-tetradecanoyl-amino-3,4-di-O-tetradecanoyl-D-glucopyranose.