Mycobacterium smegmatis-based vaccine shows promise in study

A recent study into bacteria related to the causative agent of tuberculosis found that a genetically modified version of the pathogen could serve as an effective vaccine.

The study looked into the role of the esx-3 locus in mycobacterial pathogenesis. The esx-3 locus is a part of the organism that allows for the bacteria to evade the immune system. The research team, led by K.A. Sweeney, determined that by deleting the esx-3 genes from Mycobacterium smegmatis, the bacterium could function as an novel vaccine vector with an enhanced innate immune-activating property.

When the vector was genetically engineered to express the esx-3 locus of Mycobacterium tuberculosis, the bacterium that causes the tuberculosis disease, the vector functioned as a potent vaccine against TB.

The only currently available vaccine, the Bacille Calmette-Guerin, uses prophylactic immunization with the Mycobacterium bovis bacterium. While BCG is the only vaccine available to control TB, experts have noted the ineffectiveness of BCG immunization with pulmonary TB, immunization in TB in HIV-positive infants and immunization in TB-endemic areas.

The study found that when the M. smegmatis-based vaccines were engineered to express the esx-3 of TB-causing bacteria, the vaccine was able to provide superior protection to that of BCG when administered intravenously.

The research findings could lead scientists to a new type of TB vaccine that would be more effective in TB-endemic areas.