Navigation Links
Scientists reveal how disease bacterium survives inside immune system cell

New research on a bacterium that can survive encounters with specific immune system cells has strengthened scientists' belief that these plentiful white blood cells, known as neutrophils, dictate whether our immune system will permit or prevent bacterial infections. A paper describing the research was released today online in The Journal of Immunology. Frank R. DeLeo, Ph.D., of Rocky Mountain Laboratories (RML), part of the National Institute of Allergy and Infectious Diseases (NIAID) of the National Institutes of Health, directed the work at RML, in Hamilton, MT, in collaboration with lead author Dori L. Borjesson, D.V.M., Ph.D., of the University of Minnesota in St. Paul.

Scientists analyzed how neutrophils from healthy blood donors respond to Anaplasma phagocytophilum, a tick-borne bacterium that causes granulocytic anaplasmosis in people, dogs, horses and cows. A. phagocytophilum is carried by the same tick that transmits Lyme disease and was first identified in humans in 1996. Human granulocytic anaplasmosis (HGA) -- formerly called human granulocytic ehrlichiosis -- is prevalent in Minnesota and along the East Coast. HGA typically causes mild symptoms that include fever, muscle aches and nausea. Some 362 U.S. cases were reported to the Centers for Disease Control and Prevention in 2003.

HGA is considered an emerging infectious disease, and Dr. Borjesson is working to understand how it affects blood cells -- and neutrophils in particular. "Few people know about this pathogen, but it is important because it is transmitted by ticks and causes disease in both animals and humans," Dr. Borjesson says.

Neutrophils, which make up about 60 percent of all white blood cells, are the largest cellular component of the human immune system -- billions exist inside each human. Typically, neutrophils ingest and then kill harmful bacteria by producing molecules that are toxic to cells, including a bleach-like substance called hypochlorous acid. Once the b acteria are killed, the involved neutrophils self-destruct in a process known as apoptosis. Recent evidence suggests that this process is vital to resolving human infections.

A. phagocytophilum is unusual in that it can delay apoptosis in human neutrophils, which presumably allows some of the bacteria to replicate and cause infection.

"This particular bacterium specifically seeks out neutrophils -- possibly the most lethal of all host defense cells -- and remarkably, can alter their function, multiply within them and thereby cause infection," says NIAID Director Anthony S. Fauci, M.D.

Dr. DeLeo says the findings contrast with what is known about other bacterial pathogens, most notably Staphylococcus aureus, which is of great interest because of its increasing resistance to antibiotic treatment. S. aureus, often simply referred to as "staph," are bacteria commonly found on the skin and in the noses of healthy people. Occasionally, staph can cause infection; most are minor, such as pimples, boils and other skin conditions. However, staph bacteria can also cause serious and sometimes fatal infections, such as bloodstream infections, surgical wound infections and pneumonia.

In their experiments, the research team compared the neutrophil response to A. phagocytophilum with that of a weak strain of S. aureus. Using microarray technology that allowed them to compare about 14,000 different human genes, the researchers discovered how the response to A. phagocytophilum deviates from that of S. aureus, and thus permits the HGA agent to survive.

"This study has given us a global model of how bacteria can inhibit neutrophil apoptosis," says Dr. DeLeo. "Our next step is to look at specific human genes or gene pathways within this model and try to determine which of these molecules help prolong cell life following infection." Information gathered from these and similar studies, he adds, could help researchers develop therapeutics to treat or prevent bacterial infections.


'"/>

Source:NIH/National Institute of Allergy and Infectious Diseases


Related biology news :

1. Scientists ID molecular switch in liver that triggers harmful effects of saturated and trans fats
2. Scientists Replicate Hepatitis C Virus in Laboratory
3. Scientists detect probable genetic cause of some Parkinsons disease cases
4. Scientists find missing enzyme for tuberculosis iron scavenging pathway
5. Scientists seek answers on what activates deadly anthrax spores
6. Yale Scientists Find MicroRNA Regulates Ras Cancer Gene
7. Scientists collaborate to assess health of global environment
8. Scientists decipher genome of fungus that can cause life-threatening infections
9. Scientists discover the cellular roots of graying hair
10. Scientists rid stem cell culture of key animal cells
11. Scientists develop new color-coded test for protein folding
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:2/8/2017)... The biometrics market has reached a ... organizations, desires to better authenticate or identify users ... challenge questions), biometrics is quickly working its way ... is driven by use cases, though there traditionally ... uses cases, with consumer-facing use cases encompassing authentication, ...
(Date:2/7/2017)... , Feb. 7, 2017 Zimmer Biomet Holdings, ... musculoskeletal healthcare, will present at the LEERINK Partners 6th ... Palace Hotel on Wednesday, February 15, 2017 at 10 ... of the presentation can be accessed at http://wsw.com/webcast/leerink28/zbh ... the conference via Zimmer Biomet,s Investor Relations website at ...
(Date:2/3/2017)... Feb. 3, 2017  Texas Biomedical Research Institute announced that ... Larry Schlesinger as the Institute,s new President and CEO. ... May 31, 2017. He is currently the Chair of the ... Center for Microbial Interface Biology at Ohio State University. ... new President and CEO of Texas Biomed," said Dr. ...
Breaking Biology News(10 mins):
(Date:2/17/2017)... 2017 According to a ... (Consumables, Service), Type (Safety, Efficacy, Validation), Disease Indication ... and Development, Disease-Risk) - Global Forecast to 2021" ... reach USD 53.34 Billion by 2021 from USD ... of 13.8% during the forecast period (2016-2021). ...
(Date:2/17/2017)... ... February 17, 2017 , ... Academy of Model Aeronautics (AMA), ... maker of unmanned aircraft systems (UAS), are launching a joint program to promote ... and support educational outreach efforts. , AMA and DJI will collaborate on other ...
(Date:2/16/2017)... Arbor, MI (PRWEB) , ... February 16, 2017 , ... ... 5:00-7:00 p.m. The event will be held at Avomeen Analytical Services (4840 Venture ... by a MichBio member organization. They provide an opportunity to interact with peers, make ...
(Date:2/16/2017)... 16, 2017  MDNA Life Sciences Inc. (MDNA), ... liquid biopsy tests based on the mitochondrial genome, ... license agreement with its first international commercial partner, ... test for prostate cancer, the Prostate Mitomic Test ... This is the first overseas appointment for MDNA ...
Breaking Biology Technology: