Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

High-speed images show how cells mobilize for immune response

17.04.2003


New high-speed imaging techniques are allowing scientists to show how a single cell mobilizes its resources to activate its immune response, a news research study shows.



Howard R. Petty, Ph.D., professor and biophysicist at the University of Michigan Health System’s Kellogg Eye Center, has dazzled his colleagues with movies of fluorescent-lit calcium waves that pulse through the cell, issuing an intracellular call-to-arms to attack the pathogens within.

He explains that these high-speed images provide a level of detail about cell signaling that simply wasn’t possible just a few years ago.


In the April 15 issue of the Proceedings of the National Academy of Sciences, Petty provides more detail on cell signaling, depicting what he calls the "molecular machinery" underlying the immune response. He has identified a sequence of amino acids (LTL) that controls the calcium wave pathway and, crucially, the ability of immune cells to destroy targets.

The findings are important because they could eventually lead scientists to design drugs based on the amino acid motif.

"Our clinical goal," explains Petty, "is to characterize the immune cell’s signaling function so that we can interrupt it or somehow intervene when it begins to misfire." The process has implications for treating autoimmune diseases such as arthritis, multiple sclerosis, and the eye disorder uveitis.

Through images of phagocytosis, the process by which a cell engulfs and then destroys its target, Petty is able to track the movement of calcium waves as they send signals to key players in the immune response. The "calcium wave" is a stream of calcium ions coming into the cell, which is detected by the fluorescence emission of a calcium-sensing dye.

As a cell membrane begins to surround its target, two calcium waves begin to circulate. When the target is completely surrounded, one wave traveling around the cell’s perimeter splits in two, with the second wave encircling the phagosome or sac-like compartment. This second wave allows the digestive enzymes to enter the phagosome and finally destroy the target.

When Petty introduced a mutation in the gene (FcyRIIA) that controls phagocytosis, he found that the calcium wave simply circled the cell and bypassed the phagosome altogether. As a result, the immune cell could engulf, but could not carry out the destruction of its target. This led him to conclude that the LTL sequence orchestrates the cell signaling process.

The sequence may also have a role in directing other cell activities, for example signaling the endoplasmic reticulum to form a spindle that connects the phagosome and the outer cell membrane. "The spindle seems to act as an extension cord that signals the calcium wave into the phagosome to finish the attack," suggests Petty.

Petty explains that many of these findings are possible thanks to high-speed imaging techniques that enable him to merge knowledge of physics with cell and molecular biology. He uses high sensitivity fluorescence imaging with shutter speeds 600,000 times faster than video frames.

"Before the advent of high-speed imaging, you could not ask many of these questions because we had no way to see the movement of calcium waves," he says. "With conventional imaging you ended up with a blur of calcium." By contrast, Petty’s images resemble the movement of a comet across the night sky.

In the study reported in PNAS, Petty used leucocytes as a model for the process. The amino acid sequence is in the region of the gene FcyRIIA. He is currently studying the same phenomena in the eye, where phagocytosis disposes of the regularly-shed remnants of photoreceptor cells.


The paper, Signal sequence within FcRIIA controls calcium wave propagation patterns: Apparent role in phagolysosome fusion, also appears on the PNAS internet site at www.pnas.org.

Betsy Nisbet | EurekAlert!
Further information:
http://www.pnas.org

More articles from Life Sciences:

nachricht Complementing conventional antibiotics
24.05.2018 | Goethe-Universität Frankfurt am Main

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

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Molecular switch will facilitate the development of pioneering electro-optical devices

A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.

The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...

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...

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

Surgery involving ultrasound energy found to treat high blood pressure

24.05.2018 | Medical Engineering

First chip-scale broadband optical system that can sense molecules in the mid-IR

24.05.2018 | Physics and Astronomy

Beyond the limits of conventional electronics: stable organic molecular nanowires

24.05.2018 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>