[Immunogenicity of Mycobacterium tuberculosis Rv0394c protein and its diagnosis potential for bovine tuberculosis].

To evaluate the potential of Mycobacterium tuberculosis Rv0394c protein for use in the diagnosis of bovine tuberculosis, the Rv0394c protein was expressed and purified via a prokaryotic expression system. Its immunogenicity was assessed in mouse and guinea pig models, and its stimulatory effect in peripheral blood IFN-γ release assays was analyzed. The gene fragment of Rv0394c was introduced into the prokaryotic expression vector pColdI via homologous recombination to construct the recombinant plasmid pColdI-Rv0394c, which was transformed into Escherichia coli BL21(DE3) for induced expression. The purified recombinant protein was used to immunize mice to evaluate its immunogenicity. Its diagnostic efficacy as a skin hypersensitivity antigen was assessed in guinea pigs sensitized with inactivated Mycobacterium bovis. Additionally, its potential as a specific stimulating antigen was evaluated by the peripheral blood IFN-γ release assay for bovine tuberculosis. The Rv0394c fusion protein with good immunogenicity was successfully constructed and purified. Mouse experiments showed that Rv0394c stimulated splenic lymphocytes from immunized mice to produce high levels of specific IFN-γ. Skin test results demonstrated that Rv0394c elicited strong positive reactions in sensitized guinea pigs. In the bovine peripheral blood IFN-γ release assay, Rv0394c stimulated high levels of IFN-γ production in tuberculosis-positive cattle. When being used in combination with the fusion protein CFP10-ESAT6 (CE), Rv0394c significantly improved the diagnostic sensitivity for bovine tuberculosis. Rv0394c is an immunodominant antigen with the potential to serve as an allergen for skin test diagnosis and as a stimulating antigen for the peripheral blood IFN-γ release assay in bovine tuberculosis, which provides important biological materials for the development of novel diagnostic technologies for bovine tuberculosis.