Scientists have made a significant advancement in the development of a new vaccine against tuberculosis, which is responsible for approximately 1.7 million deaths worldwide, annually.
Professor William Jacobs of Albert Einstein College of Medicine in New York has devised a prototype vaccine against the tuberculosis microbe, mycobacterium tuberculosis( MTB).
Tuberculosis is common and, in many cases, a lethally infectious disease caused by various strains of mycobacteria, usually mycobacterium tuberculosis. A high lipid content of this pathogen accounts for many of its unique clinical characteristics. It divides every 16 to 20 hours, an extremely slow rate as compared to other bacteria, which usually divide in less than an hour.
Tuberculosis usually attacks the lungs but can also affect other parts of the body. It is spread through air when people with an active MTB infection cough, sneeze, or otherwise transmit their saliva through the air. The classic symptoms are a chronic cough with blood-tinged sputum, fever, night sweats and weight loss. When people suffering from active pulmonary tuberculosis cough, sneeze, speak, sing or spit, they expel infectious aerosol droplets 0.5 to 5 µm in diameter. A single sneeze can release up to 40,000 droplets.
The existing vaccine, bacile Calmette-Guerin (BCG) provides some protection against childhood forms of the infection but is not effective against the adult lung disease, which is increasingly spreading.
Researchers led by William Jacobs determined that the key to warding off tuberculosis was to better understand how the bacterium that causes it, mycobacterium tuberculosis, circumvents the human immune system.
Most notably, those vaccinated animals that survived for more than 200 days had livers that were completely clear of TB bacteria, and nobody has ever seen that before,” Professor Jacobs said.
The study, published in Nature Medicine, cautioned that only a fifth of the mice showed such resilience, which means that the vaccine must be improved.
“We don't even know yet if it will work in humans, but it's certainly a significant step in efforts to create a better TB vaccine, Professor Jacobs added.
Professor Jacobs and his colleagues deleted a set of genes called ESX-3 from the mouse bacterium and substituted them with ESX-3 genes of the human infectious agent. Mice inoculated with the new strain survived infection with TB microbes.