Pulmonary toxicity of endotoxins: comparison of lipopolysaccharides from various bacterial species.

Lipopolysaccharides from three gram-negative bacteria isolated from bale cotton and piggery air were analyzed for their chemical composition, and their pulmonary toxicity for guinea pigs, lethal toxicity for mice, and pyrogenicity for rabbits were measured. Lipopolysaccharides from Enterobacter agglomerans and Citrobacter freundii had closely related chemical compositions; both were pyrogenic for rabbits and caused a dose-dependent influx of polymorphonuclear leukocytes into the airways of guinea pigs. The lethal toxicities of these lipopolysaccharides in mice were comparable to that of Salmonella typhimurium lipopolysaccharide, which was used as a reference. Lipopolysaccharide from Agrobacterium sp. was chemically different from those of E. agglomerans and C. freundii, did not induce any influx of polymorphonuclear leukocytes, and was only weakly toxic or pyrogenic. The low biological activity of the agrobacterial lipopolysaccharide may be due to its different chemical composition.