Efficient tuberculosis treatment in mice using chemotherapy and immunotherapy with the combined DNA vaccine encoding Ag85B, MPT-64 and MPT-83.

Although most cases of tuberculosis (TB) can be cured with antibiotics, relapse is common if patients do not continue chemotherapy for at least 6 months. Thus, improved therapeutic strategies are urgently needed. We previously found that the combined DNA vaccine encoding the Mycobacterium tuberculosis proteins Ag85B, MPT-64 and MPT-83 protected mice from TB following H37Rv challenge and considered whether this combined DNA vaccine has a therapeutic effect. In the present work, we demonstrate that boosting the efficiency of the immune system with the combined DNA vaccine may be a valuable adjunct to shorten the duration of antibacterial chemotherapy. Mice treated with the combined DNA vaccine along with isoniazid and pyrazinamide showed significantly higher interferon-gamma responses to a mixture of the three specific antigens (P<0.001), which were accompanied by a significant reduction in colony-forming unit in H37Rv-infected animals 3-5 months after treatment (P<0.001). These results suggest that the combined DNA vaccine along with conventional TB chemotherapy has strong potential for TB immunotherapy and may provide new alternatives to control the disease.