Basis for serological heterogeneity of thermostable antigens of Campylobacter jejuni

Lipopolysaccharides (LPS) were extracted from eight strains of Campylobacter jejuni and purified by enzyme treatment to remove traces of RNA, DNA, and protein. This material was used to sensitize sheep erythrocytes for the passive hemagglutination assay that is presently used to serotype C. jejuni. The results confirmed that the thermostable antigen typing scheme is based on LPS (O) antigens. The LPS after sodium dodecyl sulfate-polyacrylamide gel electrophoresis and silver staining was found to consist of a series of slow migrating bands which could not be eliminated by treatment with NaOH, urea, or EDTA. However, the use of LPS double labeled with 14C and 32P yielded evidence that the bands of high molecular weight were indeed aggregations of low-molecular-weight LPS molecules.