Featured Research

from universities, journals, and other organizations

Sugar-coated polymer is new weapon against allergies and asthma

Date:
November 22, 2009
Source:
Johns Hopkins Medical Institutions
Summary:
Scientists have developed sugar-coated polymer strands that selectively kill off cells involved in triggering aggressive allergy and asthma attacks. Their advance is a significant step toward crafting pharmaceuticals to fight these often life-endangering conditions in a new way.

Scientists at Johns Hopkins and their colleagues have developed sugar-coated polymer strands that selectively kill off cells involved in triggering aggressive allergy and asthma attacks. Their advance is a significant step toward crafting pharmaceuticals to fight these often life-endangering conditions in a new way.

For more than a decade, a team led by Bruce S. Bochner, M.D., director of the Division of Allergy and Clinical Immunology at the Johns Hopkins University School of Medicine, has studied a unique protein known as Siglec-8. This protein, whose name is an acronym for Sialic Acid-binding, Immunoglobulin-like LECtin number 8, is present on the surfaces of a few types of immune cells, including eosinophils, basophils and mast cells. These different cell types have diverse but cooperative roles in normal immune function and allergic diseases. When functioning correctly, they are a valuable aid to keeping the body healthy and infection-free. However, in allergic reactions and asthma attacks, the cells unleash an overwhelming response that typically harms the body more than it helps.

The researchers found in previous studies that when they bound antibodies that specifically target Siglec-8 to the protein on eosinophils, the cells promptly died, an effect that might be useful in stemming an allergy or asthma attack. Since producing antibodies can be expensive -- a potential roadblock to using them as pharmaceuticals in the future -- the researchers sought another way to activate this protein.

Several years ago, Bochner and his colleagues discovered an unusual sugar that could uniquely and selectively attach to and activate Siglec-8. "The trick is that you need to engage several clusters of Siglec-8 on each cell at once to trigger cell death. You're not going to be able to do that with individual sugar molecules in solution," Bochner says.

To accomplish this goal, the team developed soft, flexible polymer strands coated with the sugar, "like microscopic spaghetti candy," says Bochner.

Using cells genetically modified to produce Siglec-8 on their surfaces and cells without the protein, the researchers tested whether the polymer bound when applied to the cells. As expected, the polymer bound only to the cells that produced Siglec-8. Polymer strands without the sugar, or with different attached sugars, could not bind to the cells. Additionally, when the researchers pretreated Siglec-8-producing cells with antibodies that target the protein, the polymer couldn't attach, suggesting that it specifically targets Siglec-8 and not another protein on the cells.

The researchers validated these results further by testing whether cells adhered to polymer strands immobilized in a petri dish. Cells expressing Siglec-8 bound firmly to the polymer, but didn't bind to polymers without the Siglec-8 specific sugar.

Finally, to test the polymer in a more physiologically relevant setting, the researchers added the polymer to vials of whole human blood to see which blood cells it attached to. They found that the polymer only attached to eosinophils. Using only purified eosinophils, the researchers examined whether the polymer could kill the cells, as the targeted antibodies had in previous experiments. While their results showed that the polymer killed about 65 percent of the eosinophils over 72 hours, it was not as effective as the antibody, which killed up to 90 percent of the cells in 24 hours.

"This is initial proof that delivering the sugar through a polymer can give you the desired result of selectively engaging Siglec-8 and killing eosinophils, but we still have a long way to go," says Bochner. He and his team plan to try to optimize these results, reported in the August Journal of Pharmacology and Experimental Therapeutics, by experimenting with other formulations to deliver the sugar to cells, including more rigid polymers, those with denser sugars, or nanoparticles coated with the sugar instead of polymers.

Other researchers who participated in this study include Sherry A. Hudson and Ronald L. Schnaar of the Johns Hopkins University School of Medicine; Nicolai V. Bovin of the Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry in Russia; and Paul R. Crocker of the University of Dundee in the United Kingdom.


Story Source:

The above story is based on materials provided by Johns Hopkins Medical Institutions. Note: Materials may be edited for content and length.


Cite This Page:

Johns Hopkins Medical Institutions. "Sugar-coated polymer is new weapon against allergies and asthma." ScienceDaily. ScienceDaily, 22 November 2009. <www.sciencedaily.com/releases/2009/11/091119194126.htm>.
Johns Hopkins Medical Institutions. (2009, November 22). Sugar-coated polymer is new weapon against allergies and asthma. ScienceDaily. Retrieved April 24, 2014 from www.sciencedaily.com/releases/2009/11/091119194126.htm
Johns Hopkins Medical Institutions. "Sugar-coated polymer is new weapon against allergies and asthma." ScienceDaily. www.sciencedaily.com/releases/2009/11/091119194126.htm (accessed April 24, 2014).

Share This



More Health & Medicine News

Thursday, April 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deadly Fungus Killing Bats, Spreading in US

Deadly Fungus Killing Bats, Spreading in US

AP (Apr. 24, 2014) A disease that has killed more than six million cave-dwelling bats in the United States is on the move and wildlife biologists are worried. White Nose Syndrome, discovered in New York in 2006, has now spread to 25 states. (April 24) Video provided by AP
Powered by NewsLook.com
Companies Ramp Up Wellness to Lower Health Costs

Companies Ramp Up Wellness to Lower Health Costs

AP (Apr. 24, 2014) That little voice telling you to exercise, get in shape and get healthy is probably coming from your boss. More companies are beefing up wellness programs to try and cut down their health care costs. (April 24) Video provided by AP
Powered by NewsLook.com
Blood From World's Oldest Woman Suggests Life Limit

Blood From World's Oldest Woman Suggests Life Limit

Newsy (Apr. 24, 2014) Scientists say for the extremely elderly, their stem cells might reach a state of exhaustion. This could limit one's life span. Video provided by Newsy
Powered by NewsLook.com
FDA Wants To Ban Sales Of E-Cigarettes To Minors

FDA Wants To Ban Sales Of E-Cigarettes To Minors

Newsy (Apr. 24, 2014) The Food and Drug Administration wants to crack down on the use of e-cigarettes, banning the sale of the product to minors. Video provided by Newsy
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:
from the past week

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