title: Rough mutants defective in core and O-polysaccharide synthesis and export induce antibodies reacting in an indirect ELISA with smooth lipopolysaccharide and are less effective than Rev 1 vaccine against Brucella melitensis infection of sheep.
abstract: Classical brucellosis vaccines induce antibodies to the O-polysaccharide section of the lipopolysaccharide that interfere in serodiagnosis. Brucella rough (R) mutants lack the O-polysaccharide but their usefulness as vaccines is controversial. Here, Brucella melitensis R mutants in all main lipopolysaccharide biosynthetic pathways were evaluated in sheep in comparison with the reference B. melitensis Rev 1 vaccine. In a first experiment, these mutants were tested for ability to induce anti-O-polysaccharide antibodies, persistence and spread through target organs, and innocuousness. Using the data obtained and those of genetic studies, three candidates were selected and tested for efficacy as vaccines against a challenge infecting 100% of unvaccinated ewes. Protection by R vaccines was 54% or less whereas Rev 1 afforded 100% protection. One-third of R mutant vaccinated ewes became positive in an enzyme-linked immunosorbent assay with smooth lipopolysaccharide due to the core epitopes remaining in the mutated lipopolysaccharide. We conclude that R vaccines interfere in lipopolysaccharide immunosorbent assays and are less effective than Rev 1 against B. melitensis infection of sheep.
authors.affiliation: INRA, UR1282, Infectiologie Animale et Santé Publique, IASP, Nouzilly F-37380, France.
authors.forename: María B
authors.initials: MB
authors.lastname: Barrio
authors.forename: María J
authors.initials: MJ
authors.lastname: Grilló
authors.forename: Pilar M
authors.initials: PM
authors.lastname: Muñoz
authors.forename: Isabelle
authors.initials: I
authors.lastname: Jacques
authors.forename: David
authors.initials: D
authors.lastname: González
authors.forename: María J
authors.initials: MJ
authors.lastname: de Miguel
authors.forename: Clara M
authors.initials: CM
authors.lastname: Marín
authors.forename: Montserrat
authors.initials: M
authors.lastname: Barberán
authors.forename: Jean-J
authors.initials: JJ
authors.lastname: Letesson
authors.forename: Jean-P
authors.initials: JP
authors.lastname: Gorvel
authors.forename: Ignacio
authors.initials: I
authors.lastname: Moriyón
authors.forename: José M
authors.initials: JM
authors.lastname: Blasco
authors.forename: Michel S
authors.initials: MS
authors.lastname: Zygmunt
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000096:biosynthesis*; D001428:Bacterial Vaccines / Q000276:immunology*; D017347:Brucella melitensis / Q000276:immunology*; D002006:Brucellosis / Q000276:immunology* / Q000662:veterinary*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005612:Freeze Drying; D008070:Lipopolysaccharides / Q000096:biosynthesis* / Q000235:genetics*; D008264:Macrophages / Q000382:microbiology; D008297:Male; D051379:Mice; D009154:Mutation / Q000276:immunology; D011247:Pregnancy; D012756:Sheep; D012757:Sheep Diseases / Q000276:immunology*; D014611:Vaccination
chemical_list: D000907:Antibodies, Bacterial; D001428:Bacterial Vaccines; D008070:Lipopolysaccharides