Novel recombinant BCG coexpressing Ag85B, ESAT-6 and Rv2608 elicits significantly enhanced cellular immune and antibody responses in C57BL/6 mice.
Tuberculosis (TB) remains an enormous global health problem, and a new vaccine against TB more potent than the current inadequate vaccine, the Bacille Calmette-Guérin (BCG), is urgently needed. BCG has proven to be an effective recombinant delivery vehicle for foreign antigens because of its ability to induce long-lived specific humoral and cellular immunity. Experimental evidences have revealed that Ag85B, ESAT-6 and Rv2608 are important immunodominant antigens of Mycobacterium tuberculosis and are all promising vaccine candidate molecules. In this study, we have constructed a novel recombinant BCG (rBCG) expressing fusion protein Ag85B-ESAT6-Rv2608 and evaluated the immunogenicity of rBCG in C57BL/6 mice. Results show there is strong TB-specific CD4⁺ and CD8⁺ T lymphocytes proliferative response in mice immunized with rBCG vaccine, especially the cytotoxic CD8⁺ T cells playing an important role in protection against TB. And rBCG immunization has induced a significantly strong Th1 immune response, characterized by the increased ratio of IgG2b/IgG1. Results also show that rBCG immunization could increase the secretion of Th1 cytokines such as TNF-α and IL-2 and could decrease the secretion of Th2 cytokine IL-10. Moreover, it was shown that rBCG immunization induced a strong humoral response in mice, characterized by the elevated IgG titre. Therefore, we conclude that this rBCG immunization could increase both cellular immune response and antigen-specific humoral response significantly as compared to BCG immunization in mice. The above results illustrated that rBCG::Ag85B-ESAT6-Rv2608 is a potential candidate against M. tuberculosis for further study.
State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China.
Y
Y
Lu
Y
Y
Xu
E
E
Yang
C
C
Wang
H
H
Wang
H
H
Shen
D000217:Acyltransferases / Q000276:immunology*; D000818:Animals; D000942:Antigens, Bacterial / Q000276:immunology*; D001500:BCG Vaccine / Q000737:chemistry / Q000276:immunology*; D001426:Bacterial Proteins / Q000276:immunology*; D015153:Blotting, Western; D016207:Cytokines / Q000096:biosynthesis; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005434:Flow Cytometry; D016056:Immunodominant Epitopes / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D009163:Mycobacterium bovis / Q000276:immunology; D014376:Tuberculosis / Q000517:prevention & control*; D014614:Vaccines, Synthetic / Q000276:immunology
D000942:Antigens, Bacterial; D001500:BCG Vaccine; D001426:Bacterial Proteins; D016207:Cytokines; C093276:ESAT-6 protein, Mycobacterium tuberculosis; D016056:Immunodominant Epitopes; D014614:Vaccines, Synthetic; D000217:Acyltransferases; C121433:antigen 85B, Mycobacterium tuberculosis