14 DAY TRIAL // Experts from the Vanderbilt University Medical Center have managed to crack one of the most difficult problems in modern-day medicine, when they published a new study in the open-access journal PLoS ONE, detailing how the vaccine commonly used to fight tuberculosis (TB) could be augmented to boost its efficiency. That is to say, over the last few decades, the vaccine, which worked fine up to a point, began to yield less and less significant results, and has remained at this stage ever since. Explanations and hypotheses as to why this happened were published in the dozens, but no one has thus far been able to figure out why the vaccine had stopped inciting a strong reaction in the immune system.
In addition to offering new hope for a once-more-effective TB vaccine, the VU breakthrough could also open the way to the creation of a new class of vaccines for a host of other conditions as well, triggered by completely different pathogens. “Our findings represent nearly a 180-degree reversal from the dogma of the last 60 years – that the TB vaccine stopped working because it became over-attenuated and was too 'wimpy' to be effective,” VU Associate Professor of Medicine, Douglas Kernodle, M.D, explained.
The current TB vaccine, the BCG (bacille Calmette-Guérin), is becoming ineffective on TB strains, and has stopped inciting a strong response in the human immune system, for some reason. Experts have tried to explain this by the fact that the substance became too “soft” and too “tweaked,” and so it lost its basic properties. But the VU team has shown that, in fact, the vaccine has acquired a number of genetic traits that make the immune system less “interested” in responding to the challenge. They argue that, by removing these characteristics, the BCG vaccine – which has been around since the 1920s – could become effective once more.
“Our idea to take something away from BCG – and therefore theoretically attenuate it even further – was met with a lot of skepticism. But we believed our data that we could make BCG more immunogenic and safer. It had not become too weak – instead, by making more antioxidants it had become better at suppressing immune responses,” Kernodle added. “At each time point of the immune response, the modified BCG vaccine worked better than the parent BCG vaccine,” he shared. “By targeting antioxidants that had increased in expression during decades of cultivation, we ended up making BCG more like it was back in the 1920s when it was 80 percent effective against pulmonary TB. We fixed it.”