Nav: Home

Tuberculosis bacteria find their ecological niche

November 03, 2016

Tuberculosis (TB) is a major global public health problem. Treatment often takes many months and till this day there is no effective vaccine. Various TB bacterial strains exist globally, with different geographical spread. Only the so-called Lineage 4 occurs on all continents. It is responsible for the majority of the 10 million new infections and 2 million deaths annually.

Under the lead of Sébastien Gagneux at the Swiss Tropical and Public Health Institute (Swiss (TPH), and DZIF scientist Stefan Niemann, Research Center Borstel, a team of 75 scientists at 56 institutions analyzed the genetic make-up of TB bacteria from several thousand patients. Surprisingly, it was found that Lineage 4 can be genetically further subdivided into several sublineages. Some of these sublineages occur all over the world, others are geographically highly restricted. According to the study in the journal Nature Genetics, TB bacteria can be divided into generalists with worldwide distribution and specialists that have focused on localized ecological niche. While ecologists have been differentiating between generalists and specialists, especially in plants, for a pathogen that transmits exclusively from human to human, such a subdivision is new.

Generalists are immunologically more versatile than specialists

TB bacteria have a unique property: they hardly vary their antigens, and are thus efficiently recognized by the human immune system. As a result, a fierce immune reaction occurs, which affects the lungs in particular, and promotes coughing. Thanks to this strategy, TB bacteria is transmitted very efficiently from human to human.

The researchers show that the generalists pursue an additional strategy. They show a slightly increased diversity of their antigens compared to the specialists. "Generalists are thus able to react more specifically to the immune system of different human populations," says Stefan Niemann, who coordinates the research field "Tuberculosis" at DZIF. They have adapted their molecular strategy and are able to push through and spread much more globally.

Implications for vaccine development

These new findings have implications for the development of new TB vaccines. The more TB bacteria can adapt their antigens, the more difficult it will be to design a vaccine that is equally effective in all human populations across the world. Hence, the development of a broadly active TB vaccine might be delayed even further.

The international cooperation has made these results possible; for the German Center for Infection Research scientists from the sites Hamburg-Lübeck-Borstel, Munich and Tübingen have contributed to it as well as scientists from the African Partner Institutions. "National and international networks are the basis for the global fight against infectious diseases as HIV and TB", says DZIF Prof Michael Hoelscher, Director of the Tropical Institute in Munich, LMU. "This has been the concept for the successful work of DZIF in the research field „Tuberculosis".
-end-


German Center for Infection Research

Related Immune System Articles:

Using the immune system as a defence against cancer
Research published today in the British Journal of Cancer has found that a naturally occurring molecule and a component of the immune system that can successfully target and kill cancer cells, can also encourage immunity against cancer resurgence.
First impressions go a long way in the immune system
An algorithm that predicts the immune response to a pathogen could lead to early diagnosis for such diseases as tuberculosis
Filming how our immune system kill bacteria
To kill bacteria in the blood, our immune system relies on nanomachines that can open deadly holes in their targets.
Putting the break on our immune system's response
Researchers have discovered how a tiny molecule known as miR-132 acts as a 'handbrake' on our immune system -- helping us fight infection.
Decoding the human immune system
For the first time ever, researchers are comprehensively sequencing the human immune system, which is billions of times larger than the human genome.
Masterswitch discovered in body's immune system
Scientists have discovered a critical part of the body's immune system with potentially major implications for the treatment of some of the most devastating diseases affecting humans.
How a fungus can cripple the immune system
An international research team led by Professor Oliver Werz of Friedrich Schiller University, Jena, has now discovered how the fungus knocks out the immune defenses, enabling a potentially fatal fungal infection to develop.
How the immune system protects us against bowel cancer
Researchers from Charité - Universitätsmedizin Berlin have discovered a protective mechanism which is used by the body to protect intestinal stem cells from turning cancerous.
How herpesviruses shape the immune system
DZIF scientists at the Helmholtz Zentrum München have developed an analytic method that can very precisely detect viral infections using immune responses.
The immune system's fountain of youth
Helping the immune system clear away old cells in aging mice helped restore youthful characteristics.
More Immune System News and Immune System Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Rethinking Anger
Anger is universal and complex: it can be quiet, festering, justified, vengeful, and destructive. This hour, TED speakers explore the many sides of anger, why we need it, and who's allowed to feel it. Guests include psychologists Ryan Martin and Russell Kolts, writer Soraya Chemaly, former talk radio host Lisa Fritsch, and business professor Dan Moshavi.
Now Playing: Science for the People

#538 Nobels and Astrophysics
This week we start with this year's physics Nobel Prize awarded to Jim Peebles, Michel Mayor, and Didier Queloz and finish with a discussion of the Nobel Prizes as a way to award and highlight important science. Are they still relevant? When science breakthroughs are built on the backs of hundreds -- and sometimes thousands -- of people's hard work, how do you pick just three to highlight? Join host Rachelle Saunders and astrophysicist, author, and science communicator Ethan Siegel for their chat about astrophysics and Nobel Prizes.