To Study Immunogenicity And Protective Efficacy Of Mycobacterium Tuberculosis MPT64 Gene Recombinant Adenovirus Vaccine

Objective:To study Immunogenicity and protective efficacy of Mycobacterium tuberculosis MPT64 gene recombinant adenovirus vaccine, and provide a theoretical basis for the study of new tuberculosis vaccines.Methods:50 female C57BL/6 mice were randomly divided into 5 groups.Group A and B were immunized with the saline;Group C with empty adenovirus vector;Group D with Mycobacterium tuberculosis MPT64 recombinant adenovirus vaccine;Group E with BCG. After 4 weeks,four mice chosen randomly from each group were killed,then Stimulation index (SI) of the spleen lymphocytes was tested by MTT assay,levels of IFN-yand IL-4 in the supernants of culture were tested by ELISA.For the rest mice,except Group A,were all infected with 5×106CFU Mycobacterium tuberculosis strains H37Rv through the tail vein.4 weeks later,their left lungs and spleens were taken and weighted, pathologica changes were observed,mycobacteria cultrues were performed for 4 weeks and then the bacteria colonys were counted.Results:①ELISA assay IFN-γlevel in supernatants of spleen lymphocyte cytokines, IFN-γlevel in D group were significantly higher than A, B, C group, but no significant difference with E group;②IL-4 levels were lower in all groups, without significant difference;③MTT assay spleen lymphocyte proliferation experiments, the Stimulation index (SI) of spleen lymphocytes D group was the highest and significantly higher than A, B, C group, but no significant difference with E group;④Gross pathology results showed that lesions of lungs in D and E group was lighter than B and C group;⑤bacteria colony can't be seen in A group,and E group the least,then followed D Group. D group was less than B, C group,and no significant difference with E group.Conclusions:Preliminary experiments showed that:① Mycobacterium tuberculosis MPT64 recombinant adenovirus vaccine showed strong immunogenicity in mice, it could induce strong cellular immune response, and induction of IFN-γwith no significant difference to BCG.②Mycobacterium tuberculosis MPT64 recombinant adenovirus vaccine has strong immunogenicity against Mycobacterium tuberculosis challenge which is equivalent to the protective effect of BCG.