Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Immune-System Cells May Promote Chronic Infections


Cells sent to fight infections in the lungs of cystic fibrosis patients actually enhance the development of permanent bacterial infections, according to researchers at National Jewish Medical and Research Center. Infections with the bacteria Pseudomonas are a major cause of sickness and death in cystic fibrosis patients. The findings, published in the June issue of Infection and Immunity, suggest new treatment strategies for patients with cystic fibrosis.

"Pseudomonas can use the remnants of dead white blood cells to develop a protective biofilm, which helps the bacteria establish a permanent infection," said National Jewish pulmonologist Jerry Nick, M.D., senior author on the paper. "So, ironically, the very cells sent to fight infection may contribute to our inability to eradicate the Pseudomonas infection in cystic fibrosis patients."

Cystic fibrosis (CF) is a genetic disorder affecting about 30,000 people in the United States, and is the most common genetic disorder among Caucasian people. People with CF produce abnormal mucus that obstructs the airways and leads to chronic lung infections. The disease is fatal, but life expectancy for patients has increased dramatically in recent years, from 14 years in the mid-1980s to 35 years today. National Jewish has one of the largest adult cystic fibrosis clinics in the nation.

Pseudomonas aeruginosa is widespread in the environment and repeatedly infects most CF patients. Aggressive treatment with antibiotics successfully fights most initial infections. Over time, however, P. aeruginosa infections often become permanent; more than 80% of adults with CF are chronically infected with P. aeruginosa. The chronic infection and inflammation associated with P. aeruginosa accelerate damage to the lungs, leading ultimately to respiratory failure and death.

Researchers believe that Pseudomonas establishes a chronic infection in the airway of CF patients by creating a biofilm, a three-dimensional structure composed of bacteria encased in an extracellular matrix. Other examples of bacterial biofilms include the plaque that forms on teeth and the "slime" that forms on rocks in a stream. Bacteria in biofilms take on distinctly different characteristics from those floating free in a "planktonic" form. Once Pseudomonas develops a biofilm it becomes significantly more resistant to both antibiotics and the immune system.

The immune system attempts to eradicate Pseudomonas by sending in massive numbers of cells called neutrophils. The short-lived cells die after a short time and cellular debris accumulate in the airway of CF patients.

In a series of experiments with neutrophils and Pseudomonas, Dr. Nick and his colleagues found that the contents of dead neutrophils, particularly DNA and a filament called actin, provide a scaffolding for Pseudomonas to construct a biofilm. In the presence of neutrophils, the development of P. aeruginosa biofilms increased by two and a half to three times compared to P. aeruginosa cultures without neutrophils.

"As the neutrophils die and fall apart, their contents provide an excellent substrate for the development of biofilms," said Nick. "In turn these biofilms allow Pseudomonas to survive despite intense medical treatment."

The researchers also found that an enzyme known as DNase, which breaks apart strands of DNA, inhibits the development of biofilms. DNase is already used to break up the thick mucus that develops in the lungs of CF patients. Nick believes that it might also be useful in preventing the development of Pseudomonas biofilms.

"Once the biofilm develops, Pseudomonas infections become almost impossible to eradicate," said Nick. "If we could prevent the development of these biofilms, with DNase or other treatments, we could possibly prevent chronic infections, reduce damage to the lungs of cystic fibrosis patients, and extend their lives."

Dr. Nick and his group are now using genomic analysis to better understand how the presence of neutrophils changes the response of Pseudomonas. They hope to discover mechanisms Pseudomonas uses to avoid eradication by the immune system, which could suggest new therapies to prevent Pseudomonas infections from developing in CF patients.

William Allstetter | EurekAlert!
Further information:

More articles from Life Sciences:

nachricht First time-lapse footage of cell activity during limb regeneration
25.10.2016 | eLife

nachricht Phenotype at the push of a button
25.10.2016 | Institut für Pflanzenbiochemie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Ice shelf vibrations cause unusual waves in Antarctic atmosphere

25.10.2016 | Earth Sciences

Fluorescent holography: Upending the world of biological imaging

25.10.2016 | Power and Electrical Engineering

Etching Microstructures with Lasers

25.10.2016 | Process Engineering

More VideoLinks >>>