A. Shnyra et al., ROLE OF THE PHYSICAL STATE OF SALMONELLA LIPOPOLYSACCHARIDE IN EXPRESSION OF BIOLOGICAL AND ENDOTOXIC PROPERTIES, Infection and immunity, 61(12), 1993, pp. 5351-5360
Lipopolysaccharide (LPS) extracted from three strains of Salmonella ty
phimurium, i.e., the rough Re mutant SL1102, the rough Ra mutant TV119
, and the smooth strain SH4809, was first electrodialyzed (eLPS) and t
hen divalent cation deprived by EDTA treatment and finally made monome
ric by deoxycholate solubilization. The removal of excess detergent by
extensive dialysis in the absence of mineral cations resulted in the
reassociation of LPS subunits into monodisperse micelles of reduced ag
gregation number (dLPS) as estimated by electron microscopy and gel fi
ltration chromatography. For all LPS chemotypes tested, the developed
procedure reproducibly results in stable and clear solutions of dLPS i
n concentrations of up to 100 mg/ml. The dLPS and eLPS preparations po
ssessed the same reactivity with monoclonal antibodies (MAbs) raised a
gainst different LPS domains. The 100% lethal dose in galactosamine-se
nsitized mice of 0.01 mu g for the smooth eLPS was from 10- to 100-fol
d lower than that of dLPS at 0.1 to 1.0 mu g. dLPS from both the smoot
h strain and the Ra mutant had a significantly reduced capacity to act
ivate the proenzyme cascade in the Limulus amoebocyte lysate assay in
comparison with the slightly reduced activity of dLPS from the Re muta
nt. In contrast, dLPS as well as the deoxycholate-dispersed and then d
iluted eLPS from the smooth strain had a higher mitogenic activity on
splenocytes than eLPS. The results indicate that the biological and en
dotoxic properties of LPS are significantly influenced by the physical
state of its aggregates in aqueous solutions. The approach developed
for production of a stable and dispersed form of LPS should further as
sist in investigation of LPS properties and interpretation of the data
of endotoxic research.