Cases of tuberculosis (TB) are growing worldwide, with four deaths every minute, and two million deaths annually. It is the leading cause of death among people with HIV infection, causing around a quarter of HIV-related deaths. Being able to give people a shot that treats HIV and protects against TB would be a major breakthrough for this vulnerable group of people, and Chinese researchers have brought this possibility a step closer with a study published in Clinical and Vaccine Immunology.
Infection with Mycobacterium tuberculosis, the bacterium that causes TB, can be active (causing disease) or latent (dormant), and latent infection is 20-30 times more likely to become active in people infected with HIV. The researchers used four antigens from M tuberculosis and the p24 protein from HIV to create a DNA vaccine.
In mice, the vaccine triggered an immune response against M tuberculosis. The HIV protein acted as a carrier for the TB antigens, improving the immune response to these, as well as triggering a robust immune response to HIV. When the vaccinated mice were infected with M tuberculosis, they had lower levels of bacteria in their lungs compared with unvaccinated mice, as well as less inflammation.
The next step will be to find out whether this approach will work in latent M tuberculosis infection. If so, it could lead to an effective treatment of HIV infection, as well as stopping latent infection developing into full-blown disease.