PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

How invariant natural killers keep tuberculosis in check

2014-01-03
(Press-News.org) Contact information: Samuel Behar, M.D., Ph.D.
samuel.behar@umassmed.edu
774-455-3682
Public Library of Science
How invariant natural killers keep tuberculosis in check

Mycobacterium tuberculosis is a major cause of death worldwide, and a formidable foe. Most healthy people can defend themselves against tuberculosis, but they need all parts of their immune system to work together. A study published on January 2nd in PLOS Pathogens reveals how a special class of immune cells called "invariant natural killer T cells" make their contribution to this concerted effort.

"We were interested in identifying the mechanisms that different types of T cells use to control Mycobacterium tuberculosis infection", says Samuel Behar, from the University of Massachusetts Medical School, US, the senior author of the new study.

He and his colleagues had previously shown that when invariant natural killer T (iNKT) cells encounter infected macrophages--the human target cells of Mycobacterium tuberculosis, or Mtb--the iNKT cells somehow prevented Mtb from growing and multiplying inside the macrophages.

In this study, the scientists focused on how the iNKT cells achieved this. Using a number of cell culture systems and experiments in mice to dissect the interaction, they found that when iNKT cells are confronted with Mtb-infected macrophages, they respond in two different ways. One is that they produce and release interferon gamma, a broad-spectrum immune system activator. But when the scientists blocked interferon gamma action, they found that the iNKT cells could still inhibit Mtb growth in the macrophages.

After testing a few more known mediators of iNKT cell function and finding that they were dispensable as well, the scientists discovered that Mtb control depends on production and release by the iNKT cells of a soluble immune system factor called GM-CSF. When they blocked GM-CSF, they found that iNKT cells could no longer restrict mycobacterial growth. And when they exposed isolated Mtb-infected macrophages to GM-CSF, it turned out that this factor alone was sufficient to inhibit Mtb growth.

These results are exciting in the context of previous findings that mice in which the GM-CSF gene had been deleted were more susceptible to Mtb infection, because they link iNKT cells and GM-CSF and identify a novel pathway of Mtb control by the immune system.

Overall, the scientists say "Understanding how iNKT cells contribute to the control and elimination of Mtb in general and finding that GM-CSF has an essential function could lead to novel therapeutic approaches that strengthen their activity and boost the overall immune response during infection".



INFORMATION:

Funding:

This work was supported by National Institutes of Health (NIH) R01HL080330 to SMB, T32AR007530 supporting ACR, the American Lung Association postdoctoral research training fellowship, RT-123085-N, and Harvard University Center for AIDS Research (CFAR) Scholar Award, an NIH funded program, P30AI060354, to PJ, and a PhD fellowship from Fundac¸a˜o para a Cieˆncia e Tecnologia (Portugal) to CNA. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing Interests:

The authors have declared that no competing interests exist.

Citation:

Rothchild AC, Jayaraman P, Nunes-Alves C, Behar SM (2014) iNKT Cell Production of GM-CSF Controls Mycobacterium tuberculosis. PLoS Pathog 10(1):e1003805. doi:10.1371/journal.ppat.1003805



ELSE PRESS RELEASES FROM THIS DATE:

Call for better social science research transparency

2014-01-03
Call for better social science research transparency In the Friday (Jan. 3) edition of the journal Science, an interdisciplinary group is calling on scholars, funders, journal editors and reviewers to adopt more stringent and transparent standards ...

Study: Having Medicaid increases emergency room visits

2014-01-03
Study: Having Medicaid increases emergency room visits Unique study on Oregon's citizens sheds light on critical care in the US CAMBRIDGE, Mass. -- Adults who are covered by Medicaid use emergency rooms 40 percent more than those in similar circumstances ...

Environment affects an organism's complexity

2014-01-03
Environment affects an organism's complexity Press release from PLOS Computational Biology Scientists have demonstrated that organisms with greater complexity are more likely to evolve in complex environments, according to research published this week ...

El Nino tied to melting of Antarctica's Pine Island Glacier

2014-01-03
El Nino tied to melting of Antarctica's Pine Island Glacier Pine Island Glacier is one of the biggest routes for ice to flow from Antarctica into the sea. The floating ice shelf at the glacier's tip has been melting and thinning for the past four decades, causing the ...

Are sweetpotato weevils differentially attracted to certain colors?

2014-01-03
Are sweetpotato weevils differentially attracted to certain colors? Different colors attract sweetpotato weevils, depending on external conditions The sweetpotato weevil, Cylas formicarius (Fabricius), is the most serious pest of sweetpotato ...

Methane hydrates and global warming

2014-01-03
Methane hydrates and global warming Dissolution of hydrates off Svalbard caused by natural processes Methane hydrates are fragile. At the sea floor the ice-like solid fuel composed of water and methane is only stable at high pressure ...

Pine Island Glacier sensitive to climatic variability

2014-01-03
Pine Island Glacier sensitive to climatic variability A new study published in Science this month suggests the thinning of Pine Island Glacier in West Antarctica is much more susceptible to climatic and ocean variability than at first thought. Observations by a ...

Molecule discovered that protects the brain from cannabis intoxication

2014-01-03
Molecule discovered that protects the brain from cannabis intoxication Two INSERM research teams led by Pier Vincenzo Piazza and Giovanni Marsicano (INSERM Unit 862 "Neurocentre Magendie" in Bordeaux) ...

Animal cells can communicate by reaching out and touching, UCSF team discovers

2014-01-03
Animal cells can communicate by reaching out and touching, UCSF team discovers Signaling through direct contact not restricted to neurons, as previously thought In a finding that directly contradicts the standard biological model of animal cell ...

Study explaining parasite gene expression could help fight toxoplasmosis and malaria

2014-01-03
Study explaining parasite gene expression could help fight toxoplasmosis and malaria INDIANAPOLIS -- A newly identified protein and other proteins it interacts with could become effective targets for new drugs to control the parasite that cause toxoplasmosis, researchers ...

LAST 30 PRESS RELEASES:

High Mountain Asia’s shrinking glaciers linked to monsoon changes

All DRII-ed up: How do plants recover after drought?

Research on stigma says to just ‘shake it off’

Scientists track lightning “pollution” in real time using NASA satellite

Millions of women rely on contraceptives, but new Rice study shows they may do more than just prevent pregnancy

Hot days make for icy weather, Philippine study finds

Roxana Mehran, MD, receives the most prestigious award given by the European Society of Cardiology

World's first clinical trial showing lubiprostone aids kidney function

Capturing language change through the genes

Public trust in elections increases with clear facts

Thawing permafrost raised carbon dioxide levels after the last ice age

New DNA test reveals plants’ hidden climate role

Retinitis pigmentosa mouse models reflect pathobiology of human RP59

Cell’s ‘antenna’ could be key to curing diseases

Tiny ocean partnership between algae and bacteria reveals secrets of evolution

Scientists uncover cellular “toolkit” to reprogram immune cells for cancer therapy

Blocking protein control pathway slows rhabdomyosarcoma growth in mice

2026 Hertz Fellowship Application Now Open

The gut immune system is altered in mouse model of Alzheimer’s, providing a new target for therapeutics

ADHD drugs are being prescribed too quickly to preschoolers

UCLA scientists develop off-the-shelf immunotherapy for metastatic kidney cancer

Extreme heat linked to spike in domestic violence calls in New Orleans, study finds

Mount Sinai-Duke University study identifies DNA variants that increase testosterone production in PCOS patients

Physiology-guided complete revascularization in older patients with myocardial infarction

Metals and sulfate in air pollution mixture may contribute most to asthma hospitalizations

Understanding the profound yet hidden effects of neglect on white matter structures

SEOULTECH researchers develop revolutionary 3D-printed smart materials create high-performance pressure sensors for wearables

Pusan National University scientists develop self-deploying material for next-gen robotics

Remote screening for asymptomatic atrial fibrillation

Inflammation may explain why women with no standard modifiable risk factors have heart attacks and strokes

[Press-News.org] How invariant natural killers keep tuberculosis in check