Featured Research

from universities, journals, and other organizations

How invariant natural killers keep tuberculosis in check

Date:
January 3, 2014
Source:
Public Library of Science
Summary:
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 new study reveals how a special class of immune cells called "invariant natural killer T cells" make their contribution to this concerted effort.

This shows macrophages infected with Mycobacterium tuberculosis.
Credit: Alissa Rothchild, CC-BY

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."


Story Source:

The above story is based on materials provided by Public Library of Science. Note: Materials may be edited for content and length.


Journal Reference:

  1. Alissa C. Rothchild, Pushpa Jayaraman, Clαudio Nunes-Alves, Samuel M. Behar. iNKT Cell Production of GM-CSF Controls Mycobacterium tuberculosis. PLoS Pathogens, 2014; 10 (1): e1003805 DOI: 10.1371/journal.ppat.1003805

Cite This Page:

Public Library of Science. "How invariant natural killers keep tuberculosis in check." ScienceDaily. ScienceDaily, 3 January 2014. <www.sciencedaily.com/releases/2014/01/140103085626.htm>.
Public Library of Science. (2014, January 3). How invariant natural killers keep tuberculosis in check. ScienceDaily. Retrieved September 23, 2014 from www.sciencedaily.com/releases/2014/01/140103085626.htm
Public Library of Science. "How invariant natural killers keep tuberculosis in check." ScienceDaily. www.sciencedaily.com/releases/2014/01/140103085626.htm (accessed September 23, 2014).

Share This



More Health & Medicine News

Tuesday, September 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Liberia Pleads for Help to Fight Ebola

Liberia Pleads for Help to Fight Ebola

AP (Sep. 22, 2014) — Liberia's finance minister is urging the international community to quickly follow through on pledges of cash to battle Ebola. Bodies are piling up in the capital Monrovia as the nation awaits more help. (Sept. 22) Video provided by AP
Powered by NewsLook.com
Ebola Doctor Says Border Controls Critical

Ebola Doctor Says Border Controls Critical

AP (Sep. 22, 2014) — A Florida doctor who helped fight the expanding Ebola outbreak in West Africa says the disease can be stopped, but only if nations quickly step up their response and make border control a priority. (Sept. 22) Video provided by AP
Powered by NewsLook.com
Global Ebola Aid Increasing But Critics Say It's Late

Global Ebola Aid Increasing But Critics Say It's Late

Newsy (Sep. 21, 2014) — More than 100 tons of medical supplies were sent to West Africa on Saturday, but aid workers say the global response is still sluggish. Video provided by Newsy
Powered by NewsLook.com
Sierra Leone in Lockdown to Control Ebola

Sierra Leone in Lockdown to Control Ebola

AP (Sep. 21, 2014) — Sierra Leone residents remained in lockdown on Saturday as part of a massive effort to confine millions of people to their homes in a bid to stem the biggest Ebola outbreak in history. (Sept. 20) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins