[ALL 98 strains of Brucella OMP25 gene is conservative in China].

Objective: To investigate the genetic polymorphism of OMP25 gene isolated from 116 Brucella strains, including 18 Brucella reference strains and 98 Chinese field strains.

Methods: Chromosomal DNA of Brucella strains were analyzed by PCR, and then the product OMP25 gene was digested with Hind III and separated on 10% polypropylene agarose gel electrophoresis. OMP25 genes of different types were sequenced.

Results: Eight gene types (I-VIII) existing in 116 strains were examined, among them type II and VII were only found in certain wild strains. Sequencing analysis of OMP25 revealed only 10 sites varied in all 8 types. OMP25 of 98 Chinese Brucella strains was highly homologic and characteristic of stable antigen.

Conclusion: High conservation characteristics helps to epidemiologically detect Brucella in China as well as to found a theoretical basis for vaccine development.