Human brucellosis is characterized by the presence of both acute inflammato
ry episodes and chronic inflammation with granuloma formation. On this basi
s, the proinflammatory effects of smooth lipopolysaccharide of Brucella (S-
LPS) were addressed and compared to those of LPS from Escherichia coli. For
this purpose, the induction of cyclooxygenase-2 (COX-2), the production of
the chemokine monocyte chemoattractant protein-1 (MCP-1), and the activati
on of the nuclear factor kappaB (NF-kappaB) were studied. S-LPS was found t
o induce both COX-2 expression and MCP-1 production; however, the potency o
f E. coli LPS exceeded that of Brucella S-LPS by some orders of magnitude.
However, at concentrations above 1 mug/ml, all of the LPS produced comparab
le effects, including their ability to activate the NF-kappaB system. These
observations help explain the inflammatory events associated with Brucella
infection and the ability of Brucella to produce monocyte recruitment and
granuloma formation. (C) 2001 Elsevier Science.