Tuberculosis (TB), caused by the human pathogen Mycobacterium tuberculosis (Mtb), is an
infectious disease that presents a major threat to human health. Bacillus Calmette-Guérin (BCG), the only licensed TB
vaccine, is ineffective against latent TB
infection, necessitating the development of further TB drugs or therapeutic
vaccines. Herein, we evaluated the
therapeutic effect of a novel
subunit vaccine AEC/BC02 after
chemotherapy in a spontaneous Mtb relapse model.
Immunotherapy followed 4 weeks of treatment with
isoniazid and
rifapentine, and bacterial loads in organs, pathological changes, and adaptive immune characteristics were investigated. The results showed slowly increased bacterial loads in the spleen and lungs of mice inoculated with AEC/BC02 with significantly lower loads than those of the control groups. Pathological scores for the liver, spleen, and lungs decreased accordingly. Moreover, AEC/BC02 induced
antigen-specific IFN-γ-secreting or IL-2-secreting cellular immune responses, which decreased with the number of immunizations and times. Obvious Ag85b- and EC-specific
IgG were observed in mice following the treatment with AEC/BC02, indicating a significant Th1-biased response. Taken together, these data suggest that AEC/BC02
immunotherapy post-
chemotherapy may shorten future TB treatment.