Identification Of Linear B-Cell Epitope Of Structural Protein Bp26of Brucella. Abortus

Brucellosis caused by Brucella is a highly contagious and acutely infected disease of cattle, pigs, sheep, goats and wild ruminant species. It has an economically devastating impact on affected countries, where it creates great losses to productivity and considerable economic losses to the husbandry industry. BP26have good effects, is from inside the cells of the week outside soluble protein release, relative to the fixed membrane protein, which is easy to the characteristics of the test. BP26brucellosis in all strains of similarity is higher, so suitable for brucellosis diagnostic antigens.In order to identify the linear B-cell epitope of structural protein BP26of Brucella. Abortus, the BP26protein was dissected into three overlapping fragments, and expressed in Escherichia coli, respectively. Western blot analysis of the three fused proteins was carried out with sera from Brucella infected cattle. The results showed that the linear B-cell epitope of BP26protein is located in the51～165aa. Based on these, the short peptide protein BP262was dissected into five overlapping fragments further. Finally, we identified that the linear B cell epitope on BP26is located in the109～141amino acid. It was concluded that the MAbs against the protein BP26could be useful tools for futher studying on the structure and function of BP26, as well as for development of diagnostic methods. At the basic, six pairs of oligonucleotides overlaying BP26～2.4were designed respectively. Each pairs of oligonucleotides was cloned into the expression vector pET-32a. The expression proteins were purified to analyze the antigenicity by Western blot.BP26-2.4.3(118～127aa)BP262.4.4(123～132aa) were incubated with the positive serum. For the purpose of decreasing the numbers of amino acid, we screened the epitopes sequentially. The result of the fourth identification of the epitopes showed that the region of123～127aa is the domain epitope region of BP26.So, the linear B cell epitope on BP26is also located in the123～127amino acid of N-terminal region as serotype Asial.And this linear B cell epitope district is also belongs to other serotypes of Brucella.The results from the study may also be useful for diagnosis of Brucella infection based on antigenic epitope or developing a new strategy for vaccine design.