Abstract: Objective The recombinant Bacilli Calmette-Guérin (BCG) of rBCG-IL-12p70-TB10.4 successfully constructed was used to vaccinate in BALB/c mice to investigate its immunogenicity, and to prepare groundwork in exploring new vaccines against Mycobacterium tuberculosis (MTB). Methods Fusion gene of IL-12p70-TB10.4 was cloned into multiple cloning sites of plasmid pMV361 to construct recombinant plasmid. The recombinant plasmid was transformed into BCG using Electroportation Generator to construct MTB vaccine of rBCG-12p70-TB10.4 (rBCG-IT) and then was immunized in Balb/c mice. 3, 6, 9, 12weeks after immunization, antibody titers were evaluated by indirect ELSIA, and cellular responses were evaluated by XTT, ratios of CD4+ T and CD8+ T cells were detected by flow cytometry, and IFN-γ production was evaluated by ELISA kit. Results The recombinant vaccine of rBCG-IT was able to induce high levels of specific antibody titers, stronger proliferative responses and greater IFN-γ production, compared with BCG vaccine. Conclusion The recombinant vaccine of rBCG-IT could elicit stronger and more long-lasting humoral and cell-mediated responses compared with BCG vaccine, and was worth exploring its protective efficacy.

Key words: Recombinant BCG, IL-12p70, TB10.4, immunization efficacy