Researchers Find a Way to Compensate for BCG’s Decreasing Effectiveness over Time

10 million people are infected with tuberculosis each year and 1 million die from it. BCG undoubtedly one of the most widely used vaccines in the world is given to children to protect them against tuberculosis. However, with time, the BCG vaccine becomes less effective. To compensate for BCG’s decreasing effectiveness over time, researchers have used an antibody that blocks the IL-10 protein.

BCG Vaccine

Researchers at the Texas Biomedical Research Institute have just demonstrated in an animal model that adding an antibody to this vaccine will significantly improve its long-term effectiveness. Their work has been published in the Journal of Immunology.

BCG’s effectiveness decreases with age

Tuberculosis kills one million people a year, and more than 10 million are infected with Mycobacterium tuberculosis which primarily attacks the lungs. The weapons against this disease are antibiotics, but above all a vaccine, the BCG, vaccine is used to prevent it. Unfortunately, the effectiveness of this vaccine, which is widely used to protect children, decreases with age. Researchers are trying to remedy this.

To accomplish this, the author of the Texas Biomedical Research paper, Joanne Turner, became interested in one molecule, interleukin-10 (IL-10), and its role in tuberculosis: although IL-10 helps reduce the inflammation associated with infection, according to Joanne Turner, IL-10 can also do more harm than good and can even cause tuberculosis infection. Hence the idea of blocking and removing IL-10, which has the effect of better controlling the TB infection. But most of all, the idea of blocking IL-10 at the same time as administering the BCG vaccine.

An antibody that blocks IL-10

To achieve this, the research team used an antibody that targets the host, not the pathogen, and blocks IL-10. In animal models, this system provided better control of the infection. “By briefly blocking IL-10 while administering the vaccine, it allows the vaccine and the immune system to do their job of creating long-lasting memory immune cells,” explains Joanne Turner, adding, “We are very excited to be able to reverse the declining efficacy of BCG by combining it with a single dose of host-directed therapy, making it very practical to be used clinically.”

Following these promising results in laboratory tests with mice, the next step is to see if this combination is effective in non-human primates. Before considering clinical trials in humans.