Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists reveal how disease bacterium survives inside immune system cell

10.05.2005


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 bacteria 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.

Ken Pekoc | EurekAlert!
Further information:
http://www.niaid.nih.gov

More articles from Life Sciences:

nachricht Building a brain, cell by cell: Researchers make a mini neuron network (of two)
23.05.2018 | Institute of Industrial Science, The University of Tokyo

nachricht Research reveals how order first appears in liquid crystals
23.05.2018 | Brown University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

Im Focus: Entangled atoms shine in unison

A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.

The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

Research reveals how order first appears in liquid crystals

23.05.2018 | Life Sciences

Space-like gravity weakens biochemical signals in muscle formation

23.05.2018 | Life Sciences

NIST puts the optical microscope under the microscope to achieve atomic accuracy

23.05.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>