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Volume 48, Number 6, December 2015

Recombinant tuberculosis vaccine AEC/BC02 induces antigen-specific cellular responses in mice and protects guinea pigs in a model of latent infection 


Jin-biao Lu, Bao-wen Chen, Guo-zhi Wang, Li-li Fu, Xiao-bin Shen, Cheng Su, Wei-xin Du, Lei Yang, Miao Xu


Received: December 18, 2013    Revised: January 25, 2014    Accepted: March 26, 2014   

 

Corresponding author:

Miao Xu,
Corresponding author. Division of Tuberculosis Vaccines, National Institutes for Food and Drug Control, Number 2, Tiantan Xili, Beijing 100050, PR China. 



 

Background and purpose: 

To preliminarily evaluate the immunogenicity and efficacy of the recombinant tuberculosis vaccine AEC/BC02 in which Ag85b and fusion protein ESAT6-CFP10 were combined with bacillus Calmette-Guérin CpG and an aluminum salt-based adjuvant system. 



 

Methods:

Groups of BALB/c mice were immunized intramuscularly three times at 10-day intervals with AEC/BC02 or the adjuvant alone and the vaccine-induced cell-mediated immune responses were evaluated. The efficacy of AEC/BC02 was evaluated in two guinea pig models, one a model of prevention and the other a model of latent infection. 



 

Results:

The AEC/BC02 vaccine induced strong cellular immune responses characterized by a high frequency of antigen-specific interferon-γ-secreting T cells in mice at different time points after the last vaccination. In the preventive model of guinea pig, AEC/BC02 did not protect against Mycobacterium tuberculosis as a pre-exposure vaccine. However, in a latent infection model of guinea pig, it effectively controlled the reactivation of M. tuberculosis and lowered the bacterial load in the lung and spleen. 



 

Conclusion:

These results indicate AEC/BC02 can protect against reactivation of latent infection and may function as a therapeutic vaccine. 



 

Key words:

CpG adjuvant, guinea pig, latent tuberculosis infection, Mycobacterium tuberculosis, recombinant vaccine