Navigation Links
National Jewish Health researchers discover how virulent bacteria
Date:2/1/2010

Researchers at National Jewish Health have discovered how the virulent food-borne bacteria Listeria monocytogenes induces infected immune cells to sabotage their own defensive response. The studies offer insight into host-pathogen interactions and suggest potential therapeutic targets for food poisoning, tuberculosis and autoimmune diseases.

In the Feb. 15 issue of the Journal of Experimental Medicine, Laurel Lenz, PhD, and his colleagues report that macrophages infected by the bacteria Listeria release interferon-αβ (IFN- αβ), which makes them and nearby immune cells unresponsive to activation signals. This reduces immune resistance to the bacteria, which causes thousands of cases of food poisoning -- and more than 500 deaths -- each year in the United States.

"Listeria appears to benefit by triggering an endogenous pathway of the host that dampens its own immune response," said Dr. Lenz. "Our findings suggest that Listeria increases its survival in infected individuals by inducing cross-talk between host interferon signaling pathways."

When patrolling immune-system cells encounter non-pathogenic microbes, they normally engulf and destroy them. However, certain pathogens such as Listeria can grow within immune cells, which then release alarm signals to other nearby cells. One of these alarms is IFN-αβ. IFN-αβ protects host cells from viral infection. However, IFN- also increases growth of Listeria and certain other bacteria.

Dr. Lenz and his colleagues showed that IFN-αβ does this by down-regulating expression of receptors for interferon-γ (IFN-γ). With its receptors down-regulated, IFN-γ cannot drive resting macrophages into an activated state that is especially effective against bacterial pathogens inside the cell.

"IFN-αβ acts as a sort of anesthetic to numb the response of immune cells to IFN-γ," said Dr. Lenz.

The research highlights the crosstalk that exists between the antibacterial and anti-viral arms of the immune response. Dr. Lenz's findings demonstrate that IFN-αβ, well known to stimulate antiviral defenses, dampens anti-bacterial activity as well.

He speculates that this may be a way for the immune system to more efficiently defend against viral pathogens, while avoiding collateral damage caused by an overactive immune cells. In fact, interferon-β, a medication widely used for multiple sclerosis, may do just that. Dr. Lenz speculates that this medication may act in part by down-regulating expression of IFN- γ receptors on myeloid cells, thus reducing the stimulation of autoimmune T cells.

The next step will be to define more precisely how IFN-αβ mediates down-regulation of the IFN-γ receptors, and to determine whether prevention of these effects improves resistance to infection by Listeria and other bacterial pathogens.


'/>"/>

Contact: Adam Dormuth
dormutha@njhealth.org
303-398-1082
National Jewish Medical and Research Center
Source:Eurekalert

Related biology news :

1. Wolves find happy hunting grounds in Yellowstone National Park
2. BIO-key(R) International to Showcase Deployed Biometric Security Applications at 2007 Biometric Technology Expo
3. ESMO International Symposium on Immunology
4. Story tips from the US Department of Energys Oak Ridge National Laboratory, September 2007
5. Office of the Director of National Intelligence, CIO to Speak at Government Security Conference
6. Director of National Intelligence to Speak at Conference
7. Singapore National Science and Technology Awards
8. Conservation International and Toyota partner to protect Philippines rain forests
9. International team shows mercury concentrations in fish respond quickly to increased deposition
10. International team shows mercury concentrations in fish respond quickly to increased deposition
11. Office of the Director of National Intelligence, CIO to Speak at Government Security Conference
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:3/24/2017)... -- The Controller General of Immigration from Maldives Mr. ... have received the prestigious international IAIR Award for the most innovative high ... ... Maldives Immigration Controller ... (small picture on the right) have received the IAIR award for the ...
(Date:3/23/2017)... 23, 2017 The report "Gesture Recognition and Touchless Sensing ... Geography - Global Forecast to 2022", published by MarketsandMarkets, the market is expected ... 29.63% between 2017 and 2022. Continue Reading ... ... ...
(Date:3/22/2017)... , March 21, 2017   Neurotechnology ... object recognition technologies, today announced the release of ... (SDK), which provides improved facial recognition using up ... on a single computer. The new version uses ... improve accuracy, and it utilizes a Graphing Processing ...
Breaking Biology News(10 mins):
(Date:10/11/2017)... ... October 11, 2017 , ... The ... context, enabling overexpression experiments and avoiding the use of exogenous expression plasmids. The ... transformative for performing systematic gain-of-function studies. , This complement to loss-of-function studies, ...
(Date:10/11/2017)... BioMarketing, a leading provider of patient support solutions, has announced ... network, which will launch this week. The VMS CNEs will ... to enhance the patient care experience by delivering peer-to-peer education ... professionals to help women who have been diagnosed and are ... ...
(Date:10/11/2017)... , ... October 11, 2017 , ... ... (FDA) has granted orphan drug designation to SBT-100, its novel anti-STAT3 (Signal Transducer ... treatment of osteosarcoma. SBT-100 is able to cross the cell membrane and bind ...
(Date:10/10/2017)... ... October 10, 2017 , ... Dr. Bob Harman, founder and CEO ... Diego Rotary Club. The event entitled “Stem Cells and Their Regenerative ... attendees. Dr. Harman, DVM, MPVM was joined by two human doctors: Peter B. ...
Breaking Biology Technology: