title: Characterization of the immune response and evaluation of the protective capacity of rSsnA against Streptococcus suis infection in pigs.
abstract: The efforts made to develop vaccines against Streptococcus suis have failed because of lack of common antigens cross-reactive against different serotypes of this species. The cell wall-anchored proteins can be good vaccine candidates due to their high expression and accessibility to antibodies, among these, a cell-wall protein, DNA-nuclease (SsnA), present in most of the S. suis serotypes and clinical isolates collected from infected pigs, was selected. An experimental challenge against S. suis serotype 2 in a pig model was used to validate the efficacy of recombinant SsnA combined with aluminium hydroxide plus Quil A as adjuvants, previously tested in mice by our research group with good results. In our study, clinical characteristics, bacterial load and spread, haematological and immunological parameters and the antibody response, including the opsonophagocytosis analysis of the sera were evaluated. Moreover the composition of peripheral blood leukocyte populations was studied in infected animals. The results show that the immunization of piglets with rSsnA elicits a significant humoral antibody response. However, the antibody response is not reflected in protection of pigs that are challenged with a virulent strain in our conventional vaccination model. Further studies are necessary to evaluate the use of rSsnA as a vaccine candidate for swine.
authors.affiliation: Departamento de Sanidad Animal, Universidad de Córdoba, Campus de Excelencia Internacional CeiA3, 14071 Córdoba, Spain. Electronic address: v32gogal@uco.es.
authors.forename: Lidia
authors.initials: L
authors.lastname: Gómez-Gascón
authors.affiliation: Departamento de Sanidad Animal, Universidad de Córdoba, Campus de Excelencia Internacional CeiA3, 14071 Córdoba, Spain; CICAP-Food Research Centre, Córdoba, Pozoblanco,14400, Spain.
authors.forename: Fernando
authors.initials: F
authors.lastname: Cardoso-Toset
authors.affiliation: Departamento de Sanidad Animal, Universidad de Córdoba, Campus de Excelencia Internacional CeiA3, 14071 Córdoba, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: Tarradas
authors.affiliation: CICAP-Food Research Centre, Córdoba, Pozoblanco,14400, Spain.
authors.forename: Jaime
authors.initials: J
authors.lastname: Gómez-Laguna
authors.affiliation: Departamento de Sanidad Animal, Universidad de Córdoba, Campus de Excelencia Internacional CeiA3, 14071 Córdoba, Spain.
authors.forename: Alfonso
authors.initials: A
authors.lastname: Maldonado
authors.affiliation: Technical University of Denmark, National Veterinary Institute, Lindholm, Denmark.
authors.forename: Jens
authors.initials: J
authors.lastname: Nielsen
authors.affiliation: Departamento de Bioquímica y Biología Molecular, Universidad de Córdoba, Campus de Excelencia Internacional CeiA3, 14071 Córdoba, Spain.
authors.forename: Alfonso
authors.initials: A
authors.lastname: Olaya-Abril
authors.affiliation: Departamento de Bioquímica y Biología Molecular, Universidad de Córdoba, Campus de Excelencia Internacional CeiA3, 14071 Córdoba, Spain.
authors.forename: Manuel J
authors.initials: MJ
authors.lastname: Rodríguez-Ortega
authors.affiliation: Departamento de Sanidad Animal, Universidad de Córdoba, Campus de Excelencia Internacional CeiA3, 14071 Córdoba, Spain.
authors.forename: Inmaculada
authors.initials: I
authors.lastname: Luque
mesh_terms: D000276:Adjuvants, Immunologic; D000536:Aluminum Hydroxide / Q000276:immunology; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D058491:Bacterial Load; D002473:Cell Wall / Q000737:chemistry; D003851:Deoxyribonucleases / Q000276:immunology*; D004195:Disease Models, Animal; D056724:Immunity, Humoral; D007114:Immunization; D007958:Leukocyte Count; D010587:Phagocytosis; D062605:Quillaja Saponins / Q000276:immunology; D013290:Streptococcal Infections / Q000276:immunology* / Q000382:microbiology / Q000517:prevention & control; D022541:Streptococcal Vaccines / Q000008:administration & dosage / Q000276:immunology*; D017011:Streptococcus suis / Q000737:chemistry / Q000201:enzymology / Q000235:genetics / Q000276:immunology*; D013552:Swine; D013553:Swine Diseases / Q000517:prevention & control; D014614:Vaccines, Synthetic / Q000276:immunology
chemical_list: D000276:Adjuvants, Immunologic; D000907:Antibodies, Bacterial; D062605:Quillaja Saponins; D022541:Streptococcal Vaccines; D014614:Vaccines, Synthetic; D000536:Aluminum Hydroxide; C046386:Quil A; D003851:Deoxyribonucleases
keywords: Adjuvants; Pig model; S. suis; rSsnA