Featured Research

from universities, journals, and other organizations

Lung lesions of TB variable, independent whether infection is active or latent

Date:
December 15, 2013
Source:
University of Pittsburgh Schools of the Health Sciences
Summary:
The lung lesions in an individual infected with tuberculosis are surprisingly variable and independent of each other, despite whether the patient has clinically active or latent disease, according to a new animal study. The findings could point the way to new vaccines to prevent the hard-to-treat infection.

The lung lesions in an individual infected with tuberculosis (TB) are surprisingly variable and independent of each other, despite whether the patient has clinically active or latent disease, according to a new animal study led by researchers at the University of Pittsburgh School of Medicine. The findings, published online in Nature Medicine, could point the way to new vaccines to prevent the hard-to-treat infection.

Related Articles


More than 30 percent of the world's population is infected with Mycobacterium tuberculosis, the bacterium that causes TB, yet only 5 to 10 percent of those infected develop active, contagious disease with symptoms of coughing, chest pain, night sweats and weight loss. Most have asymptomatic, or "latent," infections that are not contagious, but could become active years later.

When the lungs become infected with M. tuberculosis, the body's immune system walls off the bacteria into lesions called granulomas, explained co-senior investigator JoAnne Flynn, Ph.D., professor of microbiology and molecular genetics, Pitt School of Medicine.

"It's long been thought that the patient with a weakened immune system or some other immune vulnerability was more likely to develop active disease," Dr. Flynn said. "But to our surprise, our study showed that every infected individual has a collection of granulomas, some containing live bacteria and some that are sterile because the immune system has killed all the bacteria. So in this sense, there's no such thing as a latent or active granuloma."

For the study, the research team infected monkeys with TB and then carefully tracked the granulomas that developed in the lungs. They determined that each granuloma starts with only one bacterium, and that bacterial replication continued for about four weeks before the body counters with an adaptive immune response to kill off the invaders.

"This response was sufficient to kill all the bacteria and sterilize some granulomas, but bacteria persisted in others and spread to create new granulomas," Dr. Flynn said. "You need only one granuloma to 'go bad' in order to get active TB."

Even when an animal had a severe, active infection, some of their granulomas were sterile, indicating the immune system was capable of killing bacteria, the researchers found.

"We don't know yet why the immune response produced different results in different lesions," Dr. Flynn said. "When we develop a deeper understanding of why the immune response produced different results in different lesions, we will be closer to harnessing the right mechanisms to develop effective vaccines to prevent TB."


Story Source:

The above story is based on materials provided by University of Pittsburgh Schools of the Health Sciences. Note: Materials may be edited for content and length.


Journal Reference:

  1. Philana Ling Lin, Christopher B Ford, M Teresa Coleman, Amy J Myers, Richa Gawande, Thomas Ioerger, James Sacchettini, Sarah M Fortune, JoAnne L Flynn. Sterilization of granulomas is common in active and latent tuberculosis despite within-host variability in bacterial killing. Nature Medicine, 2013; DOI: 10.1038/nm.3412

Cite This Page:

University of Pittsburgh Schools of the Health Sciences. "Lung lesions of TB variable, independent whether infection is active or latent." ScienceDaily. ScienceDaily, 15 December 2013. <www.sciencedaily.com/releases/2013/12/131215160937.htm>.
University of Pittsburgh Schools of the Health Sciences. (2013, December 15). Lung lesions of TB variable, independent whether infection is active or latent. ScienceDaily. Retrieved March 6, 2015 from www.sciencedaily.com/releases/2013/12/131215160937.htm
University of Pittsburgh Schools of the Health Sciences. "Lung lesions of TB variable, independent whether infection is active or latent." ScienceDaily. www.sciencedaily.com/releases/2013/12/131215160937.htm (accessed March 6, 2015).

Share This


More From ScienceDaily



More Health & Medicine News

Friday, March 6, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Just A Half-Hour Of Lost Sleep Could Lead To Weight Gain

Just A Half-Hour Of Lost Sleep Could Lead To Weight Gain

Newsy (Mar. 6, 2015) A new study found losing just half an hour of sleep could make you gain weight. Video provided by Newsy
Powered by NewsLook.com
Suicide Rates Up For Young Women In U.S.

Suicide Rates Up For Young Women In U.S.

Newsy (Mar. 6, 2015) According to a report from the CDC, suicide rates among young women increased from 1994 to 2012 while rates among young men have decreased. Video provided by Newsy
Powered by NewsLook.com
Bupa Eyes India Healthcare Opportunities

Bupa Eyes India Healthcare Opportunities

Reuters - Business Video Online (Mar. 5, 2015) Bupa is hoping to expand in India&apos;s fast-growing health insurance market, once a rule change on foreign investment is implemented. The British private healthcare group&apos;s CEO tells Grace Pascoe why it&apos;s so keen on the new opportunity. Video provided by Reuters
Powered by NewsLook.com
Liberia Releases Last Ebola Patient, But Threat Remains

Liberia Releases Last Ebola Patient, But Threat Remains

Newsy (Mar. 5, 2015) Liberia&apos;s last Ebola patient has been released, and the country hasn&apos;t recorded a new case in a week. However, fears of another outbreak still exist. Video provided by Newsy
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