Structural and antigenic properties of lipopolysaccharides from serotype reference strains of Campylobacter jejuni

Abstract

To investigate the molecular basis for heat-stable antigenic diversity in Campylobacter jejuni, lipopolysaccharides (LPSs) from serotype reference strains and serotyped isolates were examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis coupled with silver staining and immunoblotting. By silver staining, only low-Mr components, consisting of one major band and as many as three minor bands ranging in Mr from 4,500 to 5,000, were detected. However, by immunoblotting with homologous antisera, 10 of 34 strains were shown to have a series of high-Mr LPS components characteristic of molecules with 0 side chains of various lengths. Isolates of the same serotype as the reference strain that had high-Mr LPS molecules were also found to have high-Mr LPS and in one case of cross-reacting strains it was found that the cross-reaction was associated with antibodies against high-Mr LPS. The reactions of LPSs with homologous and heterologous antisera indicated that both high-and low-Mr-type LPSs were strain-specific antigens, but in some cases cross-reactions were noted. Evidently, all C. jejuni strains possess low-Mr LPS that is readily detectable by silver staining, but some serotypes also possess high-Mr LPS components that can be visualized by immunoblotting.

Current epidemiological issues in human campylobacteriosis

“…Although the PHA method will be most ef®cient for soluble antigens it had been assumed that the C. jejuni heat stable antigens were lipopolysaccharide (LPS) (Penner and Hennessey 1980). While long-chain LPS has been detected in some serotypes of C. jejuni (Preston and Penner 1987;Moran and Penner 1999 7 ), only LPS core and short-chain polysaccharides have been detected in other studies (Logan and Trust 1984) and it has been suggested that the antigen detected by PHA and direct agglutination is capsular (Chart et al 1996). Genetic studies on the Campylobacter genome have iden-ti®ed loci for both LPS/LOS and`capsule' 8 , Parkhill et al 2000.…”

The Structure and Characterization of the Surface Protein Layer of a Comamonas‐Like Organism

“…To detect the LPS, the samples were digested with proteinase K in PBS for 12 hr at 37 C and then were electrophoresed. In addition, the gel was fixed and stained with silver nitrate (20).…”

Surface components of Campylobacter and Helicobacter

“…The majority of strains were long known to express side chain-de®cient, low molecular weight outer membrane antigens of the lipo-oligosaccharide (LOS) type. In a minority (about one-third) of serotype strains a high molecular weight, protease-stable antigen capable of ladder formation on gel electrophoresis and Western blotting, characteristic of the presence of extended side chain or O-antigen of smooth lipopolysaccharide (LPS 2 ), was found (Preston and Penner 1987). The chemistry of the core structures of a number of these antigens has been explored extensively (reviewed by Fry et al 1998 andMoran andPenner 1999), indicating that the LOS type of structure has potential for expression of antigenic diversity.…”