The
lipooligosaccharides (LOS) of Campylobacter jejuni is an important
virulence factor. Its core
oligosaccharide component is frequently sialylated and bears a close resemblance with host
gangliosides. The display of
ganglioside mimics by this bacterium is believed to trigger the onset of the autoimmune condition
Guillain-Barré syndrome (GBS) in some individuals. Considerable effort has been directed toward the structural characterization of the
glycan component of the LOS of C. jejuni strains isolated from GBS patients. Capillary electrophoresis-mass spectrometry (CE-MS) has been a particularly useful analytical technique applied toward this task. Conventional analysis of bacterial LOS by CE-MS has generally involved the prior removal of O-acyl
lipid chains, which is necessary for the effective solubilization and separation of the heterogeneous ensemble of LOS species. Unfortunately, O-deacylation causes the undesired removal of important
glycan-associated O-linked modifications, such as O-
acetate and O-linked
amino acids. In this report, we describe a CE-MS technique developed for the rapid analysis of fully intact LOS from C. jejuni. Using this method, we report the structural characterization of the
glycan from 10 GBS-associated strains and two
enteritis strains, using material isolated from as little as one colony. The application of this technique has enabled us to unambiguously identify LOS-bound O-acetylated
sialic acid in a number of strains and has revealed for the first time that C. jejuni frequently modifies its core with O-linked
glycine. Our studies demonstrate that MS-based structural analysis of bacterial LOS can be optimized to the level where only a single-colony quantity of material is required and time-consuming chemical treatments can be avoided.