Specific lipopolysaccharides of Bordetella

Abstract

Specific lipopolysaccharides were extracted with warm aqueous phenol (45%, w/v) from acetone-dried cells of strains of Bordetella pertussis (Haemophilus pertussis), B. parapertussis and B. bronchisepticus and purified by differential ultra-centrifuging. The preparations contained an aldoheptose, a hexose and hexosamine, and were unusually resistant to acid hydrolysis. The B. bronchisepticus preparation contained a small amount of galactos-amine. The high N content (7.7%) of the lipopolysaccharide of B. bronchisepticus, and probably also that of B. parapertussis, could not be accounted for in terms of amino N or of nucleic acid N. Acid hydrolysis liberated ammonia, which accounted for about half of that N present in a form other than amino N. Evidence bearing on the presence of sugar acid in B. bronchisepticus lipopolysaccharide was contradictory but the amount of CO2 liberated by hot mineral acid would correspond to about 20% of hexuronic acid. The B. bronchisepticus lipopolysaccharide sedimented as 2 components in the ultracentrifuge, each of very large particle size. These components could not be distinguished chemically or serologically. The lipopolysaccharides of the Bordetella spp. were active in serological tests with homologous bacterial-cell antisera and appeared to differ among themselves in serological specificity. B. bronchisepticus lipopolysaccharide was antigenic in rabbits when combined with the conjugated-protein component of the O somatic antigen of Shigella dysenteriae. Antisera prepared against the complex formed 2 lines of precipitation with the uncombined lipopolysaccharide when examined by diffusion-precipitin analysis in agar. The lipopolysaccharides were pyrogenic. The B. pertussis preparation differed from the other 2 in being non-lethal for laboratory animals and in having a higher propoerdin activity. Acetic acid hydrolysis of B. bronchisepticus lipopolysaccharide liberated a water-soluble degraded polysaccharide, inorganic phosphate and an insoluble material which could be separated into 3 fractions by successive extractions with ether and with chloroform. The component with high N content was concentrated in the water-soluble degraded polysaccharide, which did not precipitate with homologous bacterial-cell antisera nor did it inhibit the precipitation of the intact lipopolysaccharide with these antisera. The chemical and biological properties of the Bordetella lipopolysaccharides are similar to those of the well-characterized endotoxins of certain other gram-negative bacteria. Avirulent strains of B. bronchisepticus and B. pertussis did not yield the lipopolysaccharides characteristic of virulent strains but a small amount of material was extracted with phenol from one avirulent B. bronchisepticus strain; this was similar in chemical composition to the lipopolysacharide of the virulent strain but had a different serological specificity.