An isolated or purified compound is provided, comprising A-GlcNAc[GlcNAc]-GalNAc-GalNAc-QuiNAc4NAc, wherein A is GlcNAc or Glc. There is further provided a vaccine based on such compound, having particular use to treat or prevent an infection caused by a Campylobacter organism. There is also provided an antibody or antisera against the compound, having particular use to diagnose the presence of an infection caused by a Campylobacter organism.