A team from the Institut Pasteur has recently shown that the tuberculosis bacillus hides from the immune system in its host's fat cells. This formidable pathogen is protected against even the most powerful antibiotics in these cells, in which it may remain dormant for years. This discovery, published in PLoS ONE, sheds new light on possible strategies for fighting tuberculosis. Attempts to eradicate the bacillus entirely from infected individuals should take these newly identified reservoir cells into account.
Mycobacterium tuberculosis, the bacillus responsible for tuberculosis can hide, in a dormant state, in adipose cells throughout the body. The bacterium is protected in this cellular environment, to which the natural immune defences have little access, and is inaccessible to isoniazid, one of the main antibiotics used to treat tuberculosis worldwide. These results were obtained by Olivier Neyrolles* and his colleagues from the Mycobacterial Genetics Unit directed by Brigitte Gicquel at the Institut Pasteur, in collaboration with Paul Fornès, a pathologist from Hôpital Européen Georges Pompidou. They raise questions of considerable importance in the fight against tuberculosis.
Tuberculosis kills almost two million people worldwide every year and is considered by the World Health Organisation to represent a global health emergency. However, the bacillus is much more prevalent in the world’s population than the statistics would lead us to believe, because only 5 to 10% of those infected actually develop tuberculosis. The bacillus may be present in a significant proportion of the population, remaining in a "dormant" state in the body, sometimes for years, and may be "reactivated" at any time. The risk of rea ctivation is particularly high in immunocompromised individuals, such as those infected with AIDS: the HIV virus and the tuberculosis bacillus make a formidable team, with each infectious agent facilitating the progression of the other.
Neyrolles' team first demonstrated, in cell and tissue cultures, that adipose cells served as a reservoir for Mycobacterium tuberculosis, and that this protected the bacillus against isoniazid. They then investigated whether the pathogen was present in adipose cells in humans. They did this by testing for traces of the genetic structure of the bacillus in samples from people considered not to be infected. Analyses were carried out on samples from deceased subjects from Mexico, where tuberculosis is endemic, and from Parisian districts reporting very few cases of tuberculosis.
The bacterium was detected in the adipose tissue of about a quarter of these people, all of whom were unaware they were infected, in both Mexico an d France. These results suggest that the bacillus responsible for tuberculosis can remain protected in the adipose tissue of the body in the absence of any sign of disease.
This work has important implications for the prevention of this disease. It helps to explain how, many years after first testing positive for tuberculosis, people with no trace of the microbe in the lungs may develop some form of tuberculosis attacking the lungs, bones or genitals. It also suggests that isoniazid treatment, prescribed to the close friends and family of patients as a preventative measure, may in some cases not provide sufficient protection against the disease. This is particularly important for immunocompromised patients and for people with AIDS, for whom a secondary infection with tuberculosis bacillus may have very serious consequences.
This work highlights the importance of the search for new targeted therapeutic weapons, such as new antibiotics, which must be able to reach the dormant bacillus that has been hiding in adipose cells without our knowing it.
* Olivier Neyrolles belongs to URA 2172, CNRS,
Citation: Neyrolles O, Hernández-Pando R, Pietri-Rouxel F, Fornès P, Tailleux L, et al. (2006) Is Adipose Tissue a Place for Mycobacterium tuberculosis Persistence? PLoS ONE 1(1): e43. doi:10.1371/journal.pone.0000043
Seeing on the Quick: New Insights into Active Vision in the Brain
15.08.2018 | Eberhard Karls Universität Tübingen
New Approach to Treating Chronic Itch
15.08.2018 | Universität Zürich
Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...
Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.
When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...
Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.
Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....
Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.
Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...
Scientists have discovered that the electrical resistance of a copper-oxide compound depends on the magnetic field in a very unusual way -- a finding that could help direct the search for materials that can perfectly conduct electricity at room temperatur
What happens when really powerful magnets--capable of producing magnetic fields nearly two million times stronger than Earth's--are applied to materials that...
08.08.2018 | Event News
27.07.2018 | Event News
25.07.2018 | Event News
15.08.2018 | Physics and Astronomy
15.08.2018 | Earth Sciences
15.08.2018 | Physics and Astronomy