Tuberculosis (TB) is the most common cause of death in infectious diseases; it is estimated that approximately 2 million people per year die of TB. The present available TB vaccine is a live attenuated strain, Mycobacterium bovis Bacillus Calmette Guérin (BCG). However, it has been shown that BCG has variable protective efficacy, ranging from 0 to 85% in different clinical experiments. 1 Therefore, a new TB vaccine is urgently needed. Many trials have been done to develop the second-generation TB vaccines in recent years; candidates include avirulent, auxotrophic, subunit, DNA, and recombinant vaccines. 2 The outcomes of these vaccines disappointed investigators. Encouragingly, recombinant BCG, which overexpressed the mycobacterial antigen Ag85B, produced an excellent protective response, 3,4 suggesting that a vaccine based on recombinant BCG technique was a potential approach against TB. Tuberculosis (TB) is the most common cause of death in infectious diseases; it is estimated that approximately 2 million people per year die of TB. The present available TB vaccine is a live attenuated strain, Mycobacterium bovis Bacillus Calmette Guérin (BCG). , it has been shown that the BCG has variable protective efficacy, ranging from 0 to 85% in different clinical experiments. 1 Therefore, a new TB vaccine is urgently needed. Many trials have been done to develop the second-generation TB vaccines in recent years ; include an avirulent, auxotrophic, subunit, DNA, and recombinant vaccines. 2 The outcomes of these vaccines disappointed investigators. Encouragingly, recombinant BCG, which overexpressed the mycobacterial antigen Ag85B, produced an excellent protective response, 3,4 suggesting that a vaccine based on recombinant BCG technique was a potential approach against TB.