Evaluation of three Brucella soluble antigens used in an indirect Elisa to discriminate S19 vaccinated from naturally infected cattle.
An O-polysaccharide (O-chain) and a hot-water extracted polysaccharide (PS), both obtained from Brucella abortus 1119-3, and a B. melitensis 16M native hapten (NH) were evaluated by indirect enzyme linked immunosorbent assay (ELISA) on three groups of cattle sera. The sera tested were: (a) 75 sera from cows naturally infected with B. abortus; (b) 130 sera from non-infected and non-vaccinated cattle; and (c) 61 sera from non-infected heifers recently vaccinated with B. abortus Strain 19 (S19). Sensitivity (Se), specificity (Sp) and the capability to discriminate vaccinated cattle (ADV) were determined. Using PS antigen, Se was 100% and the Sp was 97.7%, while the highest Sp was obtained by using the O-chain (99.2% ). For the NH antigen, Se was 94.7% and the Sp was 90.0%. The ADV of the three antigens was approximately 85%. Statistical analysis showed significant differences between O-chain/PS and O-chain/NH antigens. The agreement among antigens determined by kappa coefficient was 0.899 for O-chain/PS, 0.845 for O-chain/NH and 0.795 for PS/NH.
Abalos
P
P
Departamento de Medicina Preventiva Animal, Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile, Santiago. pabalos@abello.dic.uchile.cl
Daffner
J
J
Pinochet
L
L
D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D000942:Antigens, Bacterial / Q000276:immunology*; D002002:Brucella / Q000276:immunology*; D002006:Brucellosis / Q000175:diagnosis / Q000662:veterinary*; D002417:Cattle; D002418:Cattle Diseases / Q000175:diagnosis* / Q000382:microbiology; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary*; D014611:Vaccination / Q000662:veterinary
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial