Featured Research

from universities, journals, and other organizations

High-speed Images Show How Cells Mobilize For Immune Response

Date:
April 17, 2003
Source:
University Of Michigan Health System
Summary:
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.

ANN ARBOR, MI -- 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.

Related Articles


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 http://www.pnas.org.


Story Source:

The above story is based on materials provided by University Of Michigan Health System. Note: Materials may be edited for content and length.


Cite This Page:

University Of Michigan Health System. "High-speed Images Show How Cells Mobilize For Immune Response." ScienceDaily. ScienceDaily, 17 April 2003. <www.sciencedaily.com/releases/2003/04/030417075843.htm>.
University Of Michigan Health System. (2003, April 17). High-speed Images Show How Cells Mobilize For Immune Response. ScienceDaily. Retrieved November 29, 2014 from www.sciencedaily.com/releases/2003/04/030417075843.htm
University Of Michigan Health System. "High-speed Images Show How Cells Mobilize For Immune Response." ScienceDaily. www.sciencedaily.com/releases/2003/04/030417075843.htm (accessed November 29, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Saturday, November 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Rural India's Low-Cost Sanitary Pad Revolution

Rural India's Low-Cost Sanitary Pad Revolution

AFP (Nov. 28, 2014) — One man hopes his invention -– a machine that produces cheap sanitary pads –- will help empower Indian women. Duration: 01:51 Video provided by AFP
Powered by NewsLook.com
Research on Bats Could Help Develop Drugs Against Ebola

Research on Bats Could Help Develop Drugs Against Ebola

AFP (Nov. 28, 2014) — In Africa's only biosafety level 4 laboratory, scientists have been carrying out experiments on bats to understand how virus like Ebola are being transmitted, and how some of them resist to it. Duration: 01:18 Video provided by AFP
Powered by NewsLook.com
WHO Says Male Ebola Survivors Should Abstain From Sex

WHO Says Male Ebola Survivors Should Abstain From Sex

Newsy (Nov. 28, 2014) — WHO cites four studies that say Ebola can still be detected in semen up to 82 days after the onset of symptoms. Video provided by Newsy
Powered by NewsLook.com
Ebola Leaves Orphans Alone in Sierra Leone

Ebola Leaves Orphans Alone in Sierra Leone

AFP (Nov. 27, 2014) — The Ebola epidemic sweeping Sierra Leone is having a profound effect on the country's children, many of whom have been left without any family members to support them. Duration: 01:02 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins