Lipopolysaccharides: structural principles and biologic activities.

Structural principles of the three regions of the lipopolysaccharide molecule are briefly discussed. One of the recently available, chemically synthesized lipid A analogues has been tested for biologic activities. The preparation was found to be toxic, pyrogenic, and mitogenic. The amounts, however, needed for expression of effects similar to those of lipid A were about 500 times higher. These investigations are aimed at verifying the proposed structure of lipid A and at evaluating structure-activity relationships.