title: Identification and partial characterisation of a new protective antigen of Brucella abortus.
abstract: Two novel Brucella abortus proteins were isolated from B. abortus strain RB51 and their immunological properties were determined. These proteins precipitated in the 40-60% saturated concentration range of ammonium sulphate and had a molecular mass of 32.2 kDa and 22.9 kDa, respectively. Both were able to induce a strong in-vitro blast transformation in lymphoid cells obtained from mice previously sensitised with a crude brucella protein extract. The protection studies showed that the 22.9-kDa protein used as a protective immunogen was as effective as the live B. abortus RB51 vaccine but the 32.2-kDa protein had a poor protective effect under similar conditions. The amino-terminal sequence of the 22.9-kDa and 32.2-kDa proteins was determined and analysed in a database. The lack of homology with other known B. abortus proteins indicated that both proteins were novel antigens.
authors.forename: Sandra
authors.initials: S
authors.lastname: Cespedes
authors.forename: Edilia
authors.initials: E
authors.lastname: Andrews
authors.affiliation: Department of Microbiology, Faculty of Biological Sciences, Universidad de Concepción, Concepción and *Department of Immunology, Faculty of Medicine, Universidad Austral, Valdivia, Chile.
authors.forename: Hugo
authors.initials: H
authors.lastname: Folch
authors.forename: Angel
authors.initials: A
authors.lastname: Oñate
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000942:Antigens, Bacterial / Q000737:chemistry / Q000276:immunology* / Q000302:isolation & purification; D001426:Bacterial Proteins / Q000737:chemistry / Q000276:immunology / Q000302:isolation & purification; D002003:Brucella abortus / Q000737:chemistry / Q000276:immunology*; D002006:Brucellosis / Q000382:microbiology* / Q000517:prevention & control*; D002458:Cell Fractionation; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D007114:Immunization; D008198:Lymph Nodes / Q000166:cytology / Q000276:immunology; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins