Abstract：In order to obtain a Brucella vaccine candidate which can distinguish between natural infection and attenuated vaccine, this paper studied the phosphoglucomutase gene (pgm) influence on Brucella M5-90 vaccine strain virulence and immune evaluation. The recombinant plasmid pGEM-7zf-Δpgm was constructed, and which was electroporated into Brucella melitensis M5-90 competent cells, screening for Brucella vaccine strain M5-90 pgm gene deletion mutant strains (Δpgm) and to detect the M5-90 Δpgm strain genetic stability, and immunogenicity. The test results showed that the reverse mutation did not occur within 15 passages; the Δpgm antibody content and the parent strain M5-90 group had no significant difference; Δpgm had the ability to produce the IL-2 was stronger than that of M5-90, the ability to produce INF-γ was lower than the M5-90; the rose bengal plate agglutination test and tube agglutination test of this gene deletion strains was not agglutinated; the results of Western blot confirmed that the Δpgm could not induce the mice to produce anti-pgm protein antibody. The Δpgm constructed in this study, had good genetic stability and immunogenicity, provided basic data for the next step to more in-depth develop Brucella gene-deleted vaccine.
