Featured Research

from universities, journals, and other organizations

Bacteria subverts immune response to aid infection

Date:
April 26, 2012
Source:
National Jewish Health
Summary:
Listeria, one of the most deadly causes of bacterial food poisoning, subverts a normally protective immune response to spread its infection more effectively, according to new research.

Listeria, one of the most deadly causes of bacterial food poisoning, subverts a normally protective immune response to spread its infection more effectively, according to new research at National Jewish Health. Immunologists Laurel Lenz, PhD, Peter Henson, PhD, and their colleagues report online April 26, 2012, in the journal Immunity that production of nitric oxide (NO) by activated macrophages, which is normally thought of as an infection-fighting response, actually helps Listeria monocytogenes to more efficiently disseminate between infected and neighboring uninfected cells.

"In the course of evolution, pathogens and their hosts engage in an ongoing arms race, responding to and countering each other's tactics to gain the upper hand," said Dr. Lenz. "In this case, Listeria has learned to evade a response that is normally protective and to do so in a way that substantially increases the spread of infection. Several other pathogens, including Rickettsia, Burkholderia, Vaccinia and HIV, spread throughout the host in a similar manner and may use similar strategies."

When Listeria or other pathogens first enter the body, receptors on white blood cells recognize general features of the pathogen and sound an early alarm that activates the innate immune response. When activated, macrophages and other innate immune cells can more readily prevent free-floating pathogens from surviving upon entering cells. However, these activated cells also release of nitric oxide (NO), an important signaling molecule that triggers several defense mechanisms.

Dr. Lenz and his colleagues found that production of NO by activated cells helped to increase Listeria spread directly from cell to cell and replicate in its host. When Listeria spreads directly from cell to cell, it produces small buds on the surface of an infected cell. Neighboring cells that touch the infected cell absorb the buds containing the Listeria. Thus, the bacteria are transferred without ever entering the extracellular environment. The absorbed Listeria are initially contained within small bubbles, known as a vacuoles or phagosomes. Normally when a white blood cell absorbs a particle or organism, these phagosomes are targeted by a sort of cellular Death Star that fuses with them and destroys their contents. NO, however, delays the attack of these Death Stars, or lysosomes. This delay gives Listeria more time to escape the phagosome into the cell interior before it can be destroyed by the lysosomes.

"Delaying lysosome fusion with phagosomes tips the scale in favor of Listeria, allowing this pathogen to more effectively infect cells through cell-to-cell spread and thus to multiply in its host," said Dr. Lenz.


Story Source:

The above story is based on materials provided by National Jewish Health. Note: Materials may be edited for content and length.


Journal Reference:

  1. Caroline Cole, Stacey Thomas, Holly Filak, PeterM. Henson, LaurelL. Lenz. Nitric Oxide Increases Susceptibility of Toll-like Receptor-Activated Macrophages to Spreading Listeria monocytogenes. Immunity, 2012; DOI: 10.1016/j.immuni.2012.03.011

Cite This Page:

National Jewish Health. "Bacteria subverts immune response to aid infection." ScienceDaily. ScienceDaily, 26 April 2012. <www.sciencedaily.com/releases/2012/04/120426135236.htm>.
National Jewish Health. (2012, April 26). Bacteria subverts immune response to aid infection. ScienceDaily. Retrieved October 23, 2014 from www.sciencedaily.com/releases/2012/04/120426135236.htm
National Jewish Health. "Bacteria subverts immune response to aid infection." ScienceDaily. www.sciencedaily.com/releases/2012/04/120426135236.htm (accessed October 23, 2014).

Share This



More Health & Medicine News

Thursday, October 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Orthodontist Mom Jennifer Salzer on the Best Time for Braces

Orthodontist Mom Jennifer Salzer on the Best Time for Braces

Working Mother (Oct. 22, 2014) Is your child ready? Video provided by Working Mother
Powered by NewsLook.com
U.S. Issues Ebola Travel Restrictions, Are Visa Bans Next?

U.S. Issues Ebola Travel Restrictions, Are Visa Bans Next?

Newsy (Oct. 22, 2014) Now that the U.S. is restricting travel from West Africa, some are dropping questions about a travel ban and instead asking about visa bans. Video provided by Newsy
Powered by NewsLook.com
US to Track Everyone Coming from Ebola Nations

US to Track Everyone Coming from Ebola Nations

AP (Oct. 22, 2014) Stepping up their vigilance against Ebola, federal authorities said Wednesday that everyone traveling into the US from Ebola-stricken nations will be monitored for symptoms for 21 days. (Oct. 22) Video provided by AP
Powered by NewsLook.com
Doctors Help Paralysed Man Walk Again, Patient in Disbelief

Doctors Help Paralysed Man Walk Again, Patient in Disbelief

AFP (Oct. 22, 2014) Polish doctors describe how they helped a paralysed man walk again, with the patient in disbelief at the return of sensation to his legs. Duration: 1:04 Video provided by AFP
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