Researchers are testing new tuberculosis vaccine
Researchers have developed a new vaccine against tuberculosis. As the scientists at the Albert Einstein College of Medicine in New York report in the current issue of the journal "Nature Medicine", they have successfully tested a tuberculosis vaccine on mice that makes the pathogens recognizable for the immune system and thus their control by the body's own system Immune defense enabled.
The new tuberculosis vaccine has proven to be extremely efficient in the trials with mice and also offers significant advantages over previous vaccines such as the so-called Bacille Calmette-Guérin (BCG), which was developed almost a century ago, reports study leader William Jacobs. BCG has been used as the only vaccine against tuberculosis for decades, but only offered 50 to 80 percent protection against tuberculosis, according to the US researchers. Jacob further explained that the conventional tuberculosis vaccines also frequently had relatively strong side effects and that scientists have been searching intensively for a new vaccine for years.
The US researchers' approach could possibly mean a breakthrough, because unlike BCG, the new tuberculosis vaccine not only slows the growth of bacteria in the body, but is also able to completely kill the pathogens in infected tissue, emphasized study leader William Jacobs. Although the novel vaccine did not show the same effect in all mice as part of the study, the US researchers see their vaccine as the basis for future tuberculosis prevention. As Jacobs emphasized, "Neither BCG nor any vaccine currently being researched creates such an obvious or long immunity." While more research is needed, the novel vaccine appears to offer "something we've been dreaming of for years: longer protection and bacterial immunity," said the scientists at Albert Einstein College of Medicine.
Vaccine unmasked the tuberculosis bacteria The researchers led by William Jacobs derived their novel tuberculosis vaccine from the Mycobacterium smegmatis, a harmless relative of the tuberculosis bacteria (Mycobacterium tuberculosis). By blocking the so-called esx-3 gene in the Mycobacterium smegmatis, the scientists were able to remove the camouflage from the bacteria and make it recognizable for the immune system. Genetic manipulation subsequently enabled the immune system to successfully fight the bacteria, explained William Jacobs. The researchers used the genetically modified pathogens of Mycobacterium smegmatis as part of their study to vaccinate mice and then infected the animals with tuberculosis pathogens. The animals were actually immune to infections with the dangerous bacteria, the US researchers explained. According to the scientists, the pathogens in the tissues could no longer be detected in the mice that survived the longest. The protective effect is essentially due to the so-called T helper cells, which activate other immune cells and help them identify the pathogens, write William Jacobs and colleagues. According to the US researchers, the T helper cells were also able to transmit the tuberculosis protective effect after an initial vaccination with the novel vaccine. By injecting the purified T helper cells into other, previously unprotected animals, they also became immune to the dangerous infectious disease, the scientists explained.
According to the World Health Organization (WHO), nine million tuberculosis infections per year are still relatively widespread, especially in Asia, Africa and the Eastern European countries. Every year around nine million people become infected with tuberculosis and more than 1.7 million people die as a result of the infection. Infections of the lungs with persistent cough, chronic fatigue, weight loss, fever and night sweats as well as a painful stinging in the chest are typical signs of the illness also known as consumption or "the moths". Around 50 percent of untreated tuberculosis cases are fatal, warned the Robert Koch Institute (RKI), whose namesake discovered the tuberculosis bacteria in 1882, as part of World Tuberculosis Day in March this year. Anyone who discovers signs of tuberculosis should urgently consult a doctor.
Safer and more efficient tuberculosis vaccines required While the number of tuberculosis cases in Germany has been falling significantly for years, according to the WHO in Africa, Eastern Europe and some Asian countries there has been a continuous increase in tuberculosis-related infections and deaths. The US scientists led by William Jacobs consider the situation in southern Africa to be particularly worrying. This is because the increased number of HIV infections goes hand in hand with an increased proportion of fatal tuberculosis diseases. The weakened immune system of AIDS patients cannot do anything to counter the tuberculosis pathogens and the number of fatal tuberculosis diseases is correspondingly high, according to the US researchers. Therefore, according to William Jacobs and colleagues, sustainable tuberculosis vaccination protection would be particularly urgent here. But in the regions with the most tuberculosis infections and deaths, the conventional BCG vaccine has proven to be unreliable, the US researchers explained. Because a protective effect is often hardly or not at all measurable here. In addition, according to the scientists, BCG can only be used to a limited extent due to possible side effects for patients with the immunodeficiency disorder AIDS. Especially children with HIV are at risk of serious side effects, explained William Jacobs, underlining his statement that "new tuberculosis vaccines that are safer and more efficient than BCG are urgently needed". (fp)
Read about tuberculosis:
Tuberculosis: the most dangerous infectious disease
RKI warns of tuberculosis in Germany
Study: Tuberculosis increases the risk of lung cancer
Image: Thomas Siepmann / pixelio.de