title: Identification of immunoreactive extracellular proteins of Streptococcus agalactiae in bovine mastitis.
abstract: Streptococcus agalactiae is a common pathogen that causes bovine mastitis. The aims of this study were to evaluate the antibody response against S. agalactiae extracellular proteins in the whey and serum of naturally infected bovines and to identify possible immunodominant extracellular antigens. IgG1 antibodies against S. agalactiae extracellular proteins were elevated in the whey and serum of naturally infected bovines. In the whey, the levels of IgG1 specific for S. agalactiae extracellular proteins were similar in infected and noninfected milk quarters from the same cow, and the production of antibodies specific for S. agalactiae extracellular proteins was induced only by infection with this bacterium. The immunoreactivity of extracellular proteins with bovine whey was clearly different in infected versus control animals. Group B protective surface protein and 5'-nucleotidase family protein were 2 major immunoreactive proteins that were detected only in the whey of infected cows, suggesting that these proteins may be important in the pathogenesis of S. agalactiae-induced mastitis. This information could be used to diagnose S. agalactiae infection. In addition, these antigens may be useful as carrier proteins for serotype-specific polysaccharides in conjugate vaccines.
authors.affiliation: Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Trigo
authors.forename: Paula
authors.initials: P
authors.lastname: Ferreira
authors.forename: Niza
authors.initials: N
authors.lastname: Ribeiro
authors.forename: Márcia
authors.initials: M
authors.lastname: Dinis
authors.forename: Elva Bonifácio
authors.initials: EB
authors.lastname: Andrade
authors.forename: José
authors.initials: J
authors.lastname: Melo-Cristino
authors.forename: Mário
authors.initials: M
authors.lastname: Ramirez
authors.forename: Delfina
authors.initials: D
authors.lastname: Tavares
mesh_terms: D015720:5'-Nucleotidase / Q000276:immunology*; D000818:Animals; D000907:Antibodies, Bacterial / Q000032:analysis / Q000097:blood; D000942:Antigens, Bacterial / Q000276:immunology*; D000954:Antigens, Surface / Q000276:immunology*; D001426:Bacterial Proteins / Q000276:immunology*; D002417:Cattle; D005260:Female; D007074:Immunoglobulin G / Q000032:analysis / Q000097:blood; D008414:Mastitis, Bovine / Q000276:immunology* / Q000382:microbiology; D013290:Streptococcal Infections / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*; D013292:Streptococcus agalactiae / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D000954:Antigens, Surface; D001426:Bacterial Proteins; D007074:Immunoglobulin G; C447143:group B protective surface protein, S agalactiae; D015720:5'-Nucleotidase