INTERACTION OF LIPOPOLYSACCHARIDES WITH CELLS OF IMMUNOLOGICAL INTEREST

Recent progress has been made in understanding the diverse effects of bacterial endotoxin (LPS) on animal systems. Experiments from our labo ratory, as well as those from several other groups, have provided stro ng evidence supporting the presence of different sites of interaction with LPS in cells of immunological interest. However, the sequence of expression of receptors, and their interrelations, are poorly understo od. In this reveiw, we summarize the essentials of these studies, with particular emphasis on experiments from our own laboratory. Our resul ts suggest that the ''positive'' signals which trigger the activation of B lymphocytes and bone-marrrow cells, as well as the ''negative'' s ignals which trigger macrophage desensitization and tolerance to LPS, might be delivered by sparsely represented and yet unidentifed LPS rec eptors. The indentification of these molecules would clarify the mecha nisms involved in the immunostimulatory as well as in the pathophysiol ogical effects of endotoxin, and should have significant impact upon p otential therapeutic intervention in endotoxin-mediated disease.