title: The epitopic and structural characterization of Brucella suis biovar 2 O-polysaccharide demonstrates the existence of a new M-negative C-negative smooth Brucella serovar.
abstract: The brucellae are Gram-negative bacteria that cause an important zoonosis. Studies with the main Brucella species have shown that the O-antigens of the Brucella smooth lipopolysaccharide are α-(1 → 2) and α-(1 → 3)-linked N-formyl-perosamine polysaccharides that carry M, A and C (A = M, A>M and A<M) epitopes relevant in serodiagnosis and typing. We report that, in contrast to the B. suis biovar 1 O-antigen used as a reference or to all described Brucella O-antigens, B. suis biovar 2 O-antigen failed to bind monoclonal antibodies of C (A = M), C (M>A) and M specificities. However, the biovar 2 O-antigen bound monoclonal antibodies to the Brucella A epitope, and to the C/Y epitope shared by brucellae and Yersinia enterocolitica O:9, a bacterium that carries an N-formyl-perosamine O-antigen in exclusively α-(1 → 2)-linkages. By (13)C NMR spectroscopy, B. suis biovar 1 but not B. suis biovar 2 or Y. enterocolitica O:9 polysaccharide showed the signal characteristic of α-(1 → 3)-linked N-formyl-perosamine, indicating that biovar 2 may altogether lack this linkage. Taken together, the NMR spectroscopy and monoclonal antibody analyses strongly suggest a role for α-(1 → 3)-linked N-formyl-perosamine in the C (A = M) and C (M>A) epitopes. Moreover, they indicate that B. suis biovar 2 O-antigen lacks some lipopolysaccharide epitopes previously thought to be present in all smooth brucellae, thus representing a new brucella serovar that is M-negative, C-negative. Serologically and structurally this new serovar is more similar to Y. enterocolitica O:9 than to other brucellae.
authors: Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, Stockholm, Sweden.
authors: Mona V
authors: MV
authors: Zaccheus
authors: Tara
authors: T
authors: Ali
authors: Axel
authors: A
authors: Cloeckaert
authors: Michel S
authors: MS
authors: Zygmunt
authors: Andrej
authors: A
authors: Weintraub
authors: Maite
authors: M
authors: Iriarte
authors: Ignacio
authors: I
authors: Moriyón
authors: Göran
authors: G
authors: Widmalm
mesh_terms: D000907:Antibodies, Bacterial / Q000276:immunology; D000911:Antibodies, Monoclonal / Q000276:immunology; D000918:Antibody Specificity / Q000276:immunology; D041021:Brucella suis / Q000276:immunology*; D002006:Brucellosis / Q000276:immunology; D000939:Epitopes / Q000276:immunology*; D019081:O Antigens / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial; D000911:Antibodies, Monoclonal; D000939:Epitopes; D019081:O Antigens