Development in Mice of Prolonged Nonspecific Resistance to Sarcoma Implant and Staphylococcus Infection following Repository Injection of Lipopolysaccharide

Abstract

PREVIOUS reports have indicated that the injection of lipopolysaccharides (endotoxin) of Gram-negative organisms exert a profound effect on many vital functions of an animal^1,2. Particularly striking has been the development of a non-specific resistance against infection^3,5. More recently, resistance against implantation of malignant tumours has also been demonstrated following treatment with agents stimulating the reticulo-endothelial system, including lipopolysaccharides^6,7. However, use of lipopolysaccharides clinically has, so far, been frustrated in view of the hazards of fatal shock and/or infection, since the action of the endotoxin is biphasic⁴. For several hours following the injection of the lipopolysaccharide, resistance to infection is markedly decreased, but if the animal survives the shock and other physiological derangements, the resistance to infection is increased manyfold. The administration of lipopolysaccharide is particularly hazardous in experimental animals with latent or low-grade infections, converting these into acute processes often terminating in death⁸.