title: Surface array proteins of Campylobacter fetus block lectin-mediated binding to type A lipopolysaccharide.
abstract: Campylobacter fetus strains with type A lipopolysaccharide (LPS) and a surface array protein layer (S+) have been found to be pathogenic in humans and animals. Spontaneous laboratory mutants that lack surface array proteins (S-) are sensitive to the bactericidal activity of normal human serum. The ability of lectins to determine the presence of the S-layer and differentiate LPS type was assessed. We screened 14 lectins and found 3 (wheat germ agglutinin, Bandeiraea simplicifolia II, and Helix pomatia agglutinin) that agglutinated S- C. fetus strains with type A LPS but not S- strains with type B or type C LPS or S+ strains. However, the S+ type A strains were agglutinated after sequential water extraction, heat, or pronase treatment, all of which remove the S-layer, whereas there was no effect on the control strains. Specific carbohydrates for each lectin and purified LPS from a type A C. fetus strain specifically inhibited agglutination of an S- type A strain. In a direct enzyme-linked lectin assay, binding to the S- type A LPS strain was significantly greater than binding to the S+ strain (P = 0.01) or to a Campylobacter jejuni strain (P = 0.008). Consequently, these results indicate that the three lectins bind to the O side chains of C. fetus type A LPS but that the presence of the S-layer on intact cells blocks binding.
authors.affiliation: Medical Service, Veterans Administration Medical Center, Denver, Colorado 80220.
authors.forename: G C
authors.initials: GC
authors.lastname: Fogg
authors.forename: L Y
authors.initials: LY
authors.lastname: Yang
authors.forename: E
authors.initials: E
authors.lastname: Wang
authors.forename: M J
authors.initials: MJ
authors.lastname: Blaser
mesh_terms: D000372:Agglutination Tests; D002168:Campylobacter fetus / Q000145:classification* / Q000187:drug effects / Q000378:metabolism; D019286:Endopeptidase K; D037102:Lectins / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008565:Membrane Proteins / Q000494:pharmacology*; D011975:Receptors, Mitogen / Q000187:drug effects / Q000378:metabolism*; D012697:Serine Endopeptidases / Q000494:pharmacology; D013400:Sugar Acids / Q000494:pharmacology
chemical_list: D037102:Lectins; D008070:Lipopolysaccharides; D008565:Membrane Proteins; D011975:Receptors, Mitogen; D013400:Sugar Acids; C002532:2-keto-3-deoxyoctonate; D012697:Serine Endopeptidases; D019286:Endopeptidase K