Training our immune system to fight TB

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Looking at how tuberculosis (TB) bacteria interacts with our immune system, researchers in Southampton believe a more effective vaccine could be developed to better fight respiratory TB in adults.

TB is a bacterial infection that’s spread by inhaling tiny droplets from the coughs or sneezes of an infected person. Typical symptoms include tiredness and fatigue, a high fever, weight loss and a persistent cough that usually brings up phlegm which may be bloody.  

TB is a serious condition – and is responsible for more deaths worldwide than any other infectious disease – but it can be cured if treated with the right antibiotics.

To help protect against TB in the UK, the BCG vaccine is given on the NHS when a child or adult is thought to have an increased risk of coming into contact with TB. It contains a weakened strain of TB bacteria which help builds immunity and encourages the body to fight the disease if infected with it.

However, the BCG vaccine offers limited effectiveness against respiratory TB, which is the most common form of the disease in adults.

Discovering how we fight TB

New research, carried out in Southampton and published in the prestigious journal Proceedings of the National Academy of Sciences, has revealed the specific part of Mycobacterium tuberculosis, the bacteria that causes the disease, that is recognised by our immune system.

This new discovery greatly improves our understanding of how the immune system naturally fights TB and could be used to develop a more effective vaccine to prevent it.

Better understanding our immune system

“In the past, developing an effective vaccine has been a challenge as the TB-causing bacteria has developed a number of tricks to avoid being identified and eradicated by our immune system, allowing it to live safely within our bodies,” said Dr Salah Mansour, lead author for the study.

“By understanding how the body recognises and naturally fights the TB-causing bacteria,a vaccine could be developed to fast-track this process and prevent the disease taking hold.”

Looking at blood and infected lung tissue samples from TB patients allowed the team to show that specialised immune cells detect specific parts of the bacteria’s cell wall, known as mycolates.

“We created a computer simulated model to show how the immune system uses mycolates to boost the production of specialised T cells, which are special defender cells found in our bodies that protect us from infection, to target and kill the TB-causing bacteria”, explained Dr Mansour.

“The hope is that this new knowledge will boost TB vaccine development, helping to more effectively prevent this deadly disease and save many more lives.”

Posted on Monday 5 February 2018