The comparison of some biological activities of lipopolysaccharides obtained from smooth and rough Proteus mirabilis strains.

The biological activity of lipopolysaccharide (LPS) obtained from Proteus mirabilis smooth and rough strains was investigated. The tested endotoxins (differing in polysaccharide chain lenght) were isolated from wild S1959 strain as well as from its rough mutants Ra and Re. Induction of tumor necrosis factor-alpha (TNF-alpha), and nitric oxide production as well as activation of complement system by lipopolysaccharide are the pathophysiological reaction in a host response to gram-negative bacteria. In this study, it was found that S (S1959), Ra (R110) and Re (R45) chemotypes of LPS similarly induced the human neutrophils to release TNF-alpha. In contrast none of the LPS stimulated the neutrophils to synthesis of nitric oxide regardless of doses used and culture time. Te Re form of LPS showed the strongest anticomplementary activity.