title: Pathogenesis of Campylobacter fetus infections: critical role of high-molecular-weight S-layer proteins in virulence.
abstract: Wild-type Campylobacter fetus strains possess high-molecular-weight S-layer proteins (S+) and are highly resistant to serum-mediated killing and phagocytosis. Spontaneous mutant strains lacking these proteins (S-) are serum and phagocytosis sensitive and have reduced virulence in a mouse model. Intact S+ cells were treated with pronase, which made them S- although genotypically S+ and had essentially no effect on other cellular proteins or on viability. Treatment with pronase, but not buffer alone, rendered these cells serum and phagocytosis sensitive and reduced mouse virulence to the level observed for the S- mutant cells. In related studies, purified S-layer proteins diminished neutrophil chemoluminescent responses to a heterologous particulate antigen. Finally, passive administration of antiserum to the 97-kDa S-layer protein partially protected mice against lethal challenge with the S+ strain. These studies define the contribution of the S-layer proteins to C. fetus virulence.
authors.affiliation: Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232-2605.
authors.forename: M J
authors.initials: MJ
authors.lastname: Blaser
authors.forename: Z
authors.initials: Z
authors.lastname: Pei
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial / Q000502:physiology; D001426:Bacterial Proteins / Q000276:immunology*; D001770:Blood Bactericidal Activity; D002169:Campylobacter Infections / Q000276:immunology / Q000382:microbiology*; D002168:Campylobacter fetus / Q000276:immunology / Q000378:metabolism / Q000472:pathogenicity*; D007116:Immunization, Passive; D008163:Luminescent Measurements; D008562:Membrane Glycoproteins; D051379:Mice; D010587:Phagocytosis; D011402:Pronase / Q000378:metabolism; D014774:Virulence
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D008562:Membrane Glycoproteins; C055764:S-layer proteins; D011402:Pronase