Recombinant Mycobacterium smegmatis expressing an ESAT6-CFP10 fusion protein induces anti-mycobacterial immune responses and protects against Mycobacterium tuberculosis challenge in mice.
The currently used vaccine against tuberculosis, Bacille Calmette-Guérin (BCG), has variable efficacy, so new vaccine development is crucial. In this study, we evaluated a recombinant vaccine prepared from non-pathogenic Mycobacterium smegmatis (rMS) that expresses a fusion of early secreted antigenic target 6-kDa antigen (ESAT6) and culture filtrate protein 10 (CFP10). C57BL/6 mice were immunized with the rMS expressing the ESAT6-CFP10 fusion protein (rM.S-e6c10) or with BCG. The mice in the rM.S-e6c10 group had a significantly higher titre of anti-ESAT6-CFP10 antibodies than did animals in the BCG or saline groups. Spleen cells from rM.S-e6c10-immunized mice exhibited a cytotoxic response to ESAT6 and CFP10-expressed target cells, but spleen cells from animals in the other groups did not. Levels of IFN-γ and IL-2 production by purified T cells from spleens were significantly higher in rM.S-e6c10 group than in BCG group. Finally, after M. tuberculosis (MTB)-challenged mice, dramatic reduction in the numbers of MTB colony-forming units (CFUs) in the lungs was observed for the mice immunized with the rMS. The protective efficacy of rM.S-e6c10 and BCG vaccination was similar based on measures of MTB burden and lung pathology. Our data indicate that the recombinant M. smegmatis vaccine expressing the ESAT6-CFP10 fusion protein has potential in clinic application.
Zhang
H
H
Laboratory Animal Center, Fourth Military Medical University, Xi'an, China.
Peng
P
P
Miao
S
S
Zhao
Y
Y
Mao
F
F
Wang
L
L
Bai
Y
Y
Xu
Z
Z
Wei
S
S
Shi
C
C
D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D000942:Antigens, Bacterial / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D001500:BCG Vaccine / Q000008:administration & dosage / Q000276:immunology; D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D003602:Cytotoxicity, Immunologic / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D005455:Fluorescent Antibody Technique; D007114:Immunization / Q000379:methods; D007371:Interferon-gamma / Q000378:metabolism; D007376:Interleukin-2 / Q000378:metabolism; D008214:Lymphocytes / Q000276:immunology / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D020102:Mycobacterium smegmatis / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D011993:Recombinant Fusion Proteins / Q000276:immunology* / Q000378:metabolism; D013154:Spleen / Q000276:immunology / Q000378:metabolism; D014162:Transfection; D014376:Tuberculosis / Q000276:immunology / Q000517:prevention & control; D032581:Tuberculosis Vaccines / Q000008:administration & dosage / Q000276:immunology
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001500:BCG Vaccine; D001426:Bacterial Proteins; C117940:CFP-10 protein, Mycobacterium tuberculosis; C093276:ESAT-6 protein, Mycobacterium tuberculosis; D007376:Interleukin-2; D011993:Recombinant Fusion Proteins; D032581:Tuberculosis Vaccines; D007371:Interferon-gamma