Researchers develop and test a potential new tuberculosis vaccine in mice.
Tuberculosis is an infectious disease caused by the bacterium, Mycobacterium tuberculosis (Mtb). Tuberculosis is a large threat because it is able to live in a host without obvious symptoms for a period of time before becoming active. This disease resulted in 1.6 million deaths in 2017 alone. Tuberculosis has only one known, effective vaccine – Mycobacterium bovis bacille Calmette–Guérin (BCG). Though beneficial for infants needing protection, it is not suitable for long-term coverage and is not advised for those with compromised immune systems. With new, dangerous strains of tuberculosis appearing, it is beneficial to seek out alternative tuberculosis vaccines.
There is currently a sizeable amount of research being done on different possible vaccines and different modes in which vaccines can be administered. In a study by Ashhurst and colleagues, an early phase tuberculosis vaccine was made by joining two proteins – which have components usually found in Mtb – to an immune system stimulant (i.e., adjuvant). Activating the immune system in the presence of these factors could help in the future activation of the immune system during an actual Mtb infection.
To see how well the new vaccine stimulated an immune response, the tuberculosis vaccine was tested in the lungs of lab mice. The authors found that there was a successful immune response, which included T-lymphocyte, IL-17 and TNFα activity. Such activity, as well as other immune system responses, showed promise in protecting against real tuberculosis infection in mice.
Next, the effectiveness of this new vaccine was compared with the BCG vaccine. Some mice received this new tuberculosis vaccine and some received BCG. These mice were then exposed to Mtb through inhalation. The authors found that the tuberculosis vaccine generally protected against Mtb, much like BCG.
Overall, the authors showed that this new tuberculosis vaccine has some potential, though protection has so far been shown only in mice. Once in the lungs of the mice, a promising immune response was seen. Future studies would require extensive research, toxicology studies, and eventually clinical trials in order for this vaccine to be safely used in humans.
Written by Olajumoke Marissa Ologundudu, B.Sc. (Hons)
Ashhurst AS. Mucosal Vaccination with a Self-Adjuvanted Lipopeptide Is Immunogenic and Protective against Mycobacterium tuberculosis. J Med Chem. 2019. doi: 10.1021/acs.jmedchem.9b00832.
News Release: EurekAlert!. Exciting new vaccine targets killer disease TB. American Association for the Advancement of Science (AAAS). (2019). https://www.eurekalert.org/pub_releases/2019-08/ci-env082219.php