Possible basis for a new tuberculosis vaccine
Scientists have created the first tuberculosis vaccine in 100 years
American biologists have created the first tuberculosis vaccine in the last century and successfully tested its work on mice, which will help find the key to combating invulnerable strains of tuberculosis bacillus, according to an article published in the journal Applied and Environmental Microbiology (Lee et al., Engineering mycobacteria for the production of self-assembling biopolyesters displaying mycobacterial antigens for use as tuberculosis vaccine).
"We killed and disassembled the microbes, isolating the so-called bio-droplets from them. These drops are a product of nature, and they easily decompose in the body. We injected these drops into the body of the mouse and found that the immune system reacts to them. Now we need to test how such mice will react to tuberculosis infection in order to create a full–fledged vaccine," said Axel Heiser from the Hopkirk Research Institute in Palmerston (New Zealand).
Tuberculosis is today, along with cancer and heart and vascular diseases, one of the main causes of death of people on Earth, especially in countries where HIV is widespread or there are unfavorable climatic conditions. The main means to combat tuberculosis today is the BCG vaccine, developed by the French Albert Calmette and Camille Guerin back in 1921.
It is a weakened strain of bovine tuberculosis bacillus grown in special conditions and because of this has almost zero contagiousness to humans. The introduction of the vaccine into the muscle in childhood protects a person from Koch's bacillus for life, but the long-term effectiveness of BCG remains a subject of debate among scientists.
BCG is not always used and not everywhere, and there are still pockets of tuberculosis spread on Earth, and in a number of regions of the world, Koch's wand has already acquired invulnerability to the action of drugs. Therefore, the issue of creating a new tuberculosis vaccine capable of instilling immunity to new strains of Mycobacterium tuberculosis is one of the priorities in science today.
Gaiser and his colleagues found a possible solution to this problem in another bacterium. According to scientists, ordinary E. coli releases so-called bio-droplets into the environment. They are microscopic balls of polyester compounds containing fragments of proteins and other waste products.
Studying the composition of such drops, scientists noticed on their surface not only traces of proteins of the Escherichia coli itself, but also fragments of tuberculosis bacillus that accidentally got there. This led them to the idea that such drops can be used as a means of delivering Mycobacterium tuberculosis antigens to the cells of the immune system.
The problem is that the Koch wand and its closest relatives do not know how to synthesize such bio-drops. For this reason, scientists had to embed the genes associated with the production of such droplets into the genome of the Mycobacterium smegmatis microbe, a harmless "cousin" of the tuberculosis bacillus.
Having grown a culture of such GM bacteria, biologists isolated these liquid bubbles from them, collected them and injected them into the body of mice. As the first experiments have shown, such structures really cause an immune reaction, including to tuberculosis bacillus. On the other hand, it is not yet clear how mice will react to infection with "real" tuberculosis, which scientists plan to check in the near future.
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16.01.2017