title: Experimental pig yersiniosis to assess attenuation of Yersinia enterocolitica O:8 mutant strains.
abstract: An experimental oral pig model was used to assess the pathogenic and immunogenic potential of Yersinia enterocolitica serotype O:8 wild-type strain 8081-L2 and its lipopolysaccharide (LPS) mutant derivatives: a spontaneous rough mutant 8081-R2, strain 8081-DeltawzzGB expressing O-antigen with uncontrolled chain lengths, and strain 8081-wbcEGB expressing semirough LPS with only one O-unit. Microbiological and immunological parameters of the infected pigs were followed from day 7 to 60 postinfection. The wild-type and all LPS mutant strains persisted in the lymphoid tissue of tonsils and small intestines, causing asymptomatic infection without any pathological changes. Although the pig is known as a reservoir of Yersiniae, a precise analysis of pathogenic and immunogenic parameters based on different in vitro tests (hematological response, killing ability of leukocytes and blood sera, antibody response, hydrogen peroxide production by macrophages, classical and alternative pathways of complement activation), revealed significant attenuation in the pathogenicity of the LPS mutant strains but not the loss of immunogenic potential. In comparison with the other strains, strain 8081-DeltawzzGB demonstrated more continuous leucocytosis with monocytosis, higher invasive potential, significant activation of hydrogen peroxide production by macrophages and an effective immunoglobulin G immune response accompanied by relevant histological immunomorphological rearrangements.
authors.affiliation: The Stephan Angeloff Institute of Microbiology, Bulgarian Academy of Sciences, Sofia, Bulgaria. usema@bas.bg
authors.forename: Hristo
authors.initials: H
authors.lastname: Najdenski
authors.forename: Elica
authors.initials: E
authors.lastname: Golkocheva
authors.forename: Veselin
authors.initials: V
authors.lastname: Kussovski
authors.forename: Ekaterina
authors.initials: E
authors.lastname: Ivanova
authors.forename: Vasil
authors.initials: V
authors.lastname: Manov
authors.forename: Mihail
authors.initials: M
authors.lastname: Iliev
authors.forename: Anna
authors.initials: A
authors.lastname: Vesselinova
authors.forename: José Antonio
authors.initials: JA
authors.lastname: Bengoechea
authors.forename: Mikael
authors.initials: M
authors.lastname: Skurnik
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D001770:Blood Bactericidal Activity; D003170:Complement Pathway, Alternative / Q000276:immunology; D003171:Complement Pathway, Classical / Q000276:immunology; D004195:Disease Models, Animal; D006861:Hydrogen Peroxide / Q000378:metabolism; D007136:Immunoglobulins / Q000097:blood; D017737:Macrophages, Peritoneal / Q000378:metabolism; D009055:Mouth / Q000382:microbiology; D009154:Mutation; D009504:Neutrophils / Q000276:immunology; D019081:O Antigens / Q000235:genetics*; D013552:Swine; D014781:Viscera / Q000382:microbiology; D015009:Yersinia Infections / Q000276:immunology* / Q000382:microbiology*; D015008:Yersinia enterocolitica / Q000235:genetics* / Q000254:growth & development / Q000276:immunology / Q000472:pathogenicity
chemical_list: D000907:Antibodies, Bacterial; D007136:Immunoglobulins; D019081:O Antigens; D006861:Hydrogen Peroxide