Immunochemical characterization of antigens ofBrucella canis and their use in seroprevalence study of canine brucellosis

摘要

Objective:To explore immunochemical characterization of antigens ofBrucella canis (B. canis), and the use in seroprevalence study of canine brucellosis.Methods: External hot phosphate buffer saline extract(HPBSE) and internal sonicated(SA) antigens were prepared fromB. canis strainMEX 51and immunochemically characterized. These antigens were used to test527serum samples of dogs by2-mercaptoethanol-tube agglutination test (2 ME-TAT), agar gel immunodiffusion test (AGID), dot-ELISA and indirect enzyme-linked immunosorbent assay (I-ELISA) to assess the seroprevalence of canine brucellosis.Results:The protein content ofHPBSE andSAantigens was0.387 mg/mL and0.195 mg/mL, respectively, whereas carbohydrate content was0.174 mg/mL and0.150 mg/mL, respectively. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis (12.5%) ofHPBSE andSA, revealed6 and8 visible peptide bands ranging from 18-80 kDa and12-45 kDa, respectively. Western blot analysis showed immunodominant bands ofMW 12, 28, 39 and45 kDaforHPBSE and20-24 kDa for SA. TheAGID revealed HPBSEas more specific antigen thanSA but bothI-ELISA and dot-ELISA indicatedSA antigen to be more specific and reliable than HPBSE. The seroprevalence of canine brucellosis was2.27% by2ME-TAT, 1.5% byAGID, 3.03% by dot-ELISA and16.12% byI-ELISA. Conclusions: On the basis of the results of present study, we concluded thatHPBSE is suitable antigen forAGID, which is more specific; whereasSAantigen is suitable forI-ELISA, which is highly sensitive. Therefore, initial screening of serum samples should be carried out by I-ELISA followed by confirmation withAGID.